5 PL/SQL Collections and Records
PL/SQL lets you define two kinds of composite data types: collection and record.
A composite data type stores values that have internal components. You can pass entire composite variables to subprograms as parameters, and you can access internal components of composite variables individually. Internal components can be either scalar or composite. You can use scalar components wherever you can use scalar variables. You can use composite components wherever you can use composite variables of the same type.
Note:
If you pass a composite variable as a parameter to a remote subprogram, then you must create a redundant loop-back DATABASE
LINK
, so that when the remote subprogram compiles, the type checker that verifies the source uses the same definition of the user-defined composite variable type as the invoker uses.
In a collection, the internal components always have the same data type, and are called elements. You can access each element of a collection variable by its unique index, with this syntax: variable_name
(
index
)
. To create a collection variable, you either define a collection type and then create a variable of that type or use %TYPE
.
In a record, the internal components can have different data types, and are called fields. You can access each field of a record variable by its name, with this syntax: variable_name.field_name
. To create a record variable, you either define a RECORD
type and then create a variable of that type or use %ROWTYPE
or %TYPE
.
You can create a collection of records, and a record that contains collections.
Collection Topics
See Also:
-
Oracle Database SQL Language Reference for information about the
CREATE
DATABASE
LINK
statement -
"BULK COLLECT Clause" for information about retrieving query results into a collection
-
"Collection Variable Declaration" for syntax and semantics of collection type definition and collection variable declaration
Record Topics
Note:
The components of an explicitly listed composite data structure (such as a collection constructor or record initializer) can be evaluated in any order. If a program determines order of evaluation, then at the point where the program does so, its behavior is undefined.
5.1 Collection Types
PL/SQL has three collection types—associative array, VARRAY
(variable-size array), and nested table.
Table 5-1 summarizes their similarities and differences.
Table 5-1 PL/SQL Collection Types
Collection Type | Number of Elements | Index Type | Dense or Sparse | Uninitialized Status | Where Defined | Can Be ADT Attribute Data Type |
---|---|---|---|---|---|---|
Associative array (or index-by table) |
Unspecified |
String or |
Either |
Empty |
In PL/SQL block or package |
No |
|
Specified |
Integer |
Always dense |
Null |
In PL/SQL block or package or at schema level |
Only if defined at schema level |
Nested table |
Unspecified |
Integer |
Starts dense, can become sparse |
Null |
In PL/SQL block or package or at schema level |
Only if defined at schema level |
Number of Elements
If the number of elements is specified, it is the maximum number of elements in the collection. If the number of elements is unspecified, the maximum number of elements in the collection is the upper limit of the index type.
Dense or Sparse
A dense collection has no gaps between elements—every element between the first and last element is defined and has a value (the value can be NULL
unless the element has a NOT
NULL
constraint). A sparse collection has gaps between elements.
Uninitialized Status
An empty collection exists but has no elements. To add elements to an empty collection, invoke the EXTEND
method (described in "EXTEND Collection Method").
A null collection (also called an atomically null collection) does not exist. To change a null collection to an existing collection, you must initialize it, either by making it empty or by assigning a non-NULL
value to it (for details, see "Collection Constructors" and "Assigning Values to Collection Variables"). You cannot use the EXTEND
method to initialize a null collection.
Where Defined
A collection type defined in a PL/SQL block is a local type. It is available only in the block, and is stored in the database only if the block is in a standalone or package subprogram. (Standalone and package subprograms are explained in "Nested, Package, and Standalone Subprograms".)
A collection type defined in a package specification is a public item. You can reference it from outside the package by qualifying it with the package name (package_name.type_name
). It is stored in the database until you drop the package. (Packages are explained in PL/SQL Packages.)
A collection type defined at schema level is a standalone type. You create it with the "CREATE TYPE Statement". It is stored in the database until you drop it with the "DROP TYPE Statement".
Note:
A collection type defined in a package specification is incompatible with an identically defined local or standalone collection type (see Example 5-31 and Example 5-32).
Can Be ADT Attribute Data Type
To be an ADT attribute data type, a collection type must be a standalone collection type. For other restrictions, see Restrictions on datatype.
Translating Non-PL/SQL Composite Types to PL/SQL Composite Types
If you have code or business logic that uses another language, you can usually translate the array and set types of that language directly to PL/SQL collection types. For example:
Non-PL/SQL Composite Type | Equivalent PL/SQL Composite Type |
---|---|
Hash table |
Associative array |
Unordered table |
Associative array |
Set |
Nested table |
Bag |
Nested table |
Array |
|
See Also:
Oracle Database SQL Language Reference for information about the CAST
function, which converts one SQL data type or collection-typed value into another SQL data type or collection-typed value.
5.2 Associative Arrays
An associative array (formerly called PL/SQL table or index-by table) is a set of key-value pairs. Each key is a unique index, used to locate the associated value with the syntax variable_name
(
index
)
.
The data type of index
can be either a string type (VARCHAR2
, VARCHAR
, STRING
, or LONG
) or PLS_INTEGER
. Indexes are stored in sort order, not creation order. For string types, sort order is determined by the initialization parameters NLS_SORT
and NLS_COMP
.
Like a database table, an associative array:
-
Is empty (but not null) until you populate it
-
Can hold an unspecified number of elements, which you can access without knowing their positions
Unlike a database table, an associative array:
-
Does not need disk space or network operations
-
Cannot be manipulated with DML statements
Topics
See Also:
-
Table 5-1 for a summary of associative array characteristics
-
"assoc_array_type_def ::=" for the syntax of an associative array type definition
Example 5-1 Associative Array Indexed by String
This example defines a type of associative array indexed by string, declares a variable of that type, populates the variable with three elements, changes the value of one element, and prints the values (in sort order, not creation order). (FIRST
and NEXT
are collection methods, described in "Collection Methods".)
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DECLARE -- Associative array indexed by string: TYPE population IS TABLE OF NUMBER -- Associative array type INDEX BY VARCHAR2(64); -- indexed by string city_population population; -- Associative array variable i VARCHAR2(64); -- Scalar variable BEGIN -- Add elements (key-value pairs) to associative array: city_population('Smallville') := 2000; city_population('Midland') := 750000; city_population('Megalopolis') := 1000000; -- Change value associated with key 'Smallville': city_population('Smallville') := 2001; -- Print associative array: i := city_population.FIRST; -- Get first element of array WHILE i IS NOT NULL LOOP DBMS_Output.PUT_LINE ('Population of ' || i || ' is ' || city_population(i)); i := city_population.NEXT(i); -- Get next element of array END LOOP; END; /
Result:
Population of Megalopolis is 1000000 Population of Midland is 750000 Population of Smallville is 2001
Example 5-2 Function Returns Associative Array Indexed by PLS_INTEGER
This example defines a type of associative array indexed by PLS_INTEGER
and a function that returns an associative array of that type.
Live SQL:
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DECLARE TYPE sum_multiples IS TABLE OF PLS_INTEGER INDEX BY PLS_INTEGER; n PLS_INTEGER := 5; -- number of multiples to sum for display sn PLS_INTEGER := 10; -- number of multiples to sum m PLS_INTEGER := 3; -- multiple FUNCTION get_sum_multiples ( multiple IN PLS_INTEGER, num IN PLS_INTEGER ) RETURN sum_multiples IS s sum_multiples; BEGIN FOR i IN 1..num LOOP s(i) := multiple * ((i * (i + 1)) / 2); -- sum of multiples END LOOP; RETURN s; END get_sum_multiples; BEGIN DBMS_OUTPUT.PUT_LINE ( 'Sum of the first ' || TO_CHAR(n) || ' multiples of ' || TO_CHAR(m) || ' is ' || TO_CHAR(get_sum_multiples (m, sn)(n)) ); END; /
Result:
Sum of the first 5 multiples of 3 is 45
5.2.1 Declaring Associative Array Constants
When declaring an associative array constant, you must create a function that populates the associative array with its initial value and then invoke the function in the constant declaration.
For information about constructors, see "Collection Constructors".
Example 5-3 Declaring Associative Array Constant
In this example, the function does for the associative array what a constructor does for a varray or nested table.
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CREATE OR REPLACE PACKAGE My_Types AUTHID CURRENT_USER IS TYPE My_AA IS TABLE OF VARCHAR2(20) INDEX BY PLS_INTEGER; FUNCTION Init_My_AA RETURN My_AA; END My_Types; / CREATE OR REPLACE PACKAGE BODY My_Types IS FUNCTION Init_My_AA RETURN My_AA IS Ret My_AA; BEGIN Ret(-10) := '-ten'; Ret(0) := 'zero'; Ret(1) := 'one'; Ret(2) := 'two'; Ret(3) := 'three'; Ret(4) := 'four'; Ret(9) := 'nine'; RETURN Ret; END Init_My_AA; END My_Types; / DECLARE v CONSTANT My_Types.My_AA := My_Types.Init_My_AA(); BEGIN DECLARE Idx PLS_INTEGER := v.FIRST(); BEGIN WHILE Idx IS NOT NULL LOOP DBMS_OUTPUT.PUT_LINE(TO_CHAR(Idx, '999')||LPAD(v(Idx), 7)); Idx := v.NEXT(Idx); END LOOP; END; END; /
Result:
-10 -ten 0 zero 1 one 2 two 3 three 4 four 9 nine PL/SQL procedure successfully completed.
5.2.2 NLS Parameter Values Affect Associative Arrays Indexed by String
National Language Support (NLS) parameters such as NLS_SORT
, NLS_COMP
, and NLS_DATE_FORMAT
affect associative arrays indexed by string.
Topics
See Also:
Oracle Database Globalization Support Guide for information about linguistic sort parameters
5.2.2.1 Changing NLS Parameter Values After Populating Associative Arrays
The initialization parameters NLS_SORT
and NLS_COMP
determine the storage order of string indexes of an associative array.
If you change the value of either parameter after populating an associative array indexed by string, then the collection methods FIRST
, LAST
, NEXT
, and PRIOR
might return unexpected values or raise exceptions. If you must change these parameter values during your session, restore their original values before operating on associative arrays indexed by string.
5.2.2.2 Indexes of Data Types Other Than VARCHAR2
In the declaration of an associative array indexed by string, the string type must be VARCHAR2
or one of its subtypes.
However, you can populate the associative array with indexes of any data type that the TO_CHAR
function can convert to VARCHAR2
.
If your indexes have data types other than VARCHAR2
and its subtypes, ensure that these indexes remain consistent and unique if the values of initialization parameters change. For example:
-
Do not use
TO_CHAR(SYSDATE)
as an index.If the value of
NLS_DATE_FORMAT
changes, then the value of(TO_CHAR(SYSDATE))
might also change. -
Do not use different
NVARCHAR2
indexes that might be converted to the sameVARCHAR2
value. -
Do not use
CHAR
orVARCHAR2
indexes that differ only in case, accented characters, or punctuation characters.If the value of
NLS_SORT
ends in_CI
(case-insensitive comparisons) or_AI
(accent- and case-insensitive comparisons), then indexes that differ only in case, accented characters, or punctuation characters might be converted to the same value.
5.2.2.3 Passing Associative Arrays to Remote Databases
If you pass an associative array as a parameter to a remote database, and the local and the remote databases have different NLS_SORT
or NLS_COMP
values, then:
-
The collection method
FIRST
,LAST
,NEXT
orPRIOR
(described in "Collection Methods") might return unexpected values or raise exceptions. -
Indexes that are unique on the local database might not be unique on the remote database, raising the predefined exception
VALUE_ERROR
.
5.2.3 Appropriate Uses for Associative Arrays
An associative array is appropriate for:
-
A relatively small lookup table, which can be constructed in memory each time you invoke the subprogram or initialize the package that declares it
-
Passing collections to and from the database server
Declare formal subprogram parameters of associative array types. With Oracle Call Interface (OCI) or an Oracle precompiler, bind the host arrays to the corresponding actual parameters. PL/SQL automatically converts between host arrays and associative arrays indexed by
PLS_INTEGER
.Note:
You cannot bind an associative array indexed by
VARCHAR
.Note:
You cannot declare an associative array type at schema level. Therefore, to pass an associative array variable as a parameter to a standalone subprogram, you must declare the type of that variable in a package specification. Doing so makes the type available to both the invoked subprogram (which declares a formal parameter of that type) and the invoking subprogram or anonymous block (which declares and passes the variable of that type). See Example 10-2.
Tip:
The most efficient way to pass collections to and from the database server is to use associative arrays with the
FORALL
statement orBULK
COLLECT
clause. For details, see "FORALL Statement" and "BULK COLLECT Clause".
An associative array is intended for temporary data storage. To make an associative array persistent for the life of a database session, declare it in a package specification and populate it in the package body.
5.3 Varrays (Variable-Size Arrays)
A varray (variable-size array) is an array whose number of elements can vary from zero (empty) to the declared maximum size.
To access an element of a varray variable, use the syntax variable_name
(
index
)
. The lower bound of index
is 1; the upper bound is the current number of elements. The upper bound changes as you add or delete elements, but it cannot exceed the maximum size. When you store and retrieve a varray from the database, its indexes and element order remain stable.
Figure 5-1 shows a varray variable named Grades
, which has maximum size 10 and contains seven elements. Grades
(n
) references the nth element of Grades
. The upper bound of Grades
is 7, and it cannot exceed 10.
Figure 5-1 Varray of Maximum Size 10 with 7 Elements
Description of "Figure 5-1 Varray of Maximum Size 10 with 7 Elements"
The database stores a varray variable as a single object. If a varray variable is less than 4 KB, it resides inside the table of which it is a column; otherwise, it resides outside the table but in the same tablespace.
An uninitialized varray variable is a null collection. You must initialize it, either by making it empty or by assigning a non-NULL
value to it. For details, see "Collection Constructors" and "Assigning Values to Collection Variables".
Topics
See Also:
-
Table 5-1 for a summary of varray characteristics
-
"varray_type_def ::=" for the syntax of a
VARRAY
type definition -
"CREATE TYPE Statement" for information about creating standalone
VARRAY
types -
Oracle Database SQL Language Reference for more information about varrays
Example 5-4 Varray (Variable-Size Array)
This example defines a local VARRAY
type, declares a variable of that type (initializing it with a constructor), and defines a procedure that prints the varray. The example invokes the procedure three times: After initializing the variable, after changing the values of two elements individually, and after using a constructor to the change the values of all elements. (For an example of a procedure that prints a varray that might be null or empty, see Example 5-24.)
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DECLARE TYPE Foursome IS VARRAY(4) OF VARCHAR2(15); -- VARRAY type -- varray variable initialized with constructor: team Foursome := Foursome('John', 'Mary', 'Alberto', 'Juanita'); PROCEDURE print_team (heading VARCHAR2) IS BEGIN DBMS_OUTPUT.PUT_LINE(heading); FOR i IN 1..4 LOOP DBMS_OUTPUT.PUT_LINE(i || '.' || team(i)); END LOOP; DBMS_OUTPUT.PUT_LINE('---'); END; BEGIN print_team('2001 Team:'); team(3) := 'Pierre'; -- Change values of two elements team(4) := 'Yvonne'; print_team('2005 Team:'); -- Invoke constructor to assign new values to varray variable: team := Foursome('Arun', 'Amitha', 'Allan', 'Mae'); print_team('2009 Team:'); END; /
Result:
2001 Team: 1.John 2.Mary 3.Alberto 4.Juanita --- 2005 Team: 1.John 2.Mary 3.Pierre 4.Yvonne --- 2009 Team: 1.Arun 2.Amitha 3.Allan 4.Mae ---
5.4 Nested Tables
In the database, a nested table is a column type that stores an unspecified number of rows in no particular order.
When you retrieve a nested table value from the database into a PL/SQL nested table variable, PL/SQL gives the rows consecutive indexes, starting at 1. Using these indexes, you can access the individual rows of the nested table variable. The syntax is variable_name
(
index
)
. The indexes and row order of a nested table might not remain stable as you store and retrieve the nested table from the database.
The amount of memory that a nested table variable occupies can increase or decrease dynamically, as you add or delete elements.
An uninitialized nested table variable is a null collection. You must initialize it, either by making it empty or by assigning a non-NULL
value to it. For details, see "Collection Constructors" and "Assigning Values to Collection Variables".
Note:
Example 5-17, Example 5-19, and Example 5-20 reuse nt_type
and print_nt
.
Topics
See Also:
-
Table 5-1 for a summary of nested table characteristics
-
"nested_table_type_def ::=" for the syntax of a nested table type definition
-
"CREATE TYPE Statement" for information about creating standalone nested table types
-
"INSTEAD OF DML Triggers" for information about triggers that update nested table columns of views
-
Oracle Database SQL Language Reference for more information about nested tables
Example 5-5 Nested Table of Local Type
This example defines a local nested table type, declares a variable of that type (initializing it with a constructor), and defines a procedure that prints the nested table. (The procedure uses the collection methods FIRST
and LAST
, described in "Collection Methods".) The example invokes the procedure three times: After initializing the variable, after changing the value of one element, and after using a constructor to the change the values of all elements. After the second constructor invocation, the nested table has only two elements. Referencing element 3 would raise error ORA-06533.
Live SQL:
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DECLARE TYPE Roster IS TABLE OF VARCHAR2(15); -- nested table type -- nested table variable initialized with constructor: names Roster := Roster('D Caruso', 'J Hamil', 'D Piro', 'R Singh'); PROCEDURE print_names (heading VARCHAR2) IS BEGIN DBMS_OUTPUT.PUT_LINE(heading); FOR i IN names.FIRST .. names.LAST LOOP -- For first to last element DBMS_OUTPUT.PUT_LINE(names(i)); END LOOP; DBMS_OUTPUT.PUT_LINE('---'); END; BEGIN print_names('Initial Values:'); names(3) := 'P Perez'; -- Change value of one element print_names('Current Values:'); names := Roster('A Jansen', 'B Gupta'); -- Change entire table print_names('Current Values:'); END; /
Result:
Initial Values: D Caruso J Hamil D Piro R Singh --- Current Values: D Caruso J Hamil P Perez R Singh --- Current Values: A Jansen B Gupta
Example 5-6 Nested Table of Standalone Type
This example defines a standalone nested table type, nt_type
, and a standalone procedure to print a variable of that type, print_nt
. An anonymous block declares a variable of type nt_type
, initializing it to empty with a constructor, and invokes print_nt
twice: After initializing the variable and after using a constructor to the change the values of all elements.
Live SQL:
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CREATE OR REPLACE TYPE nt_type IS TABLE OF NUMBER; / CREATE OR REPLACE PROCEDURE print_nt (nt nt_type) AUTHID DEFINER IS i NUMBER; BEGIN i := nt.FIRST; IF i IS NULL THEN DBMS_OUTPUT.PUT_LINE('nt is empty'); ELSE WHILE i IS NOT NULL LOOP DBMS_OUTPUT.PUT('nt.(' || i || ') = '); DBMS_OUTPUT.PUT_LINE(NVL(TO_CHAR(nt(i)), 'NULL')); i := nt.NEXT(i); END LOOP; END IF; DBMS_OUTPUT.PUT_LINE('---'); END print_nt; / DECLARE nt nt_type := nt_type(); -- nested table variable initialized to empty BEGIN print_nt(nt); nt := nt_type(90, 9, 29, 58); print_nt(nt); END; /
Result:
nt is empty --- nt.(1) = 90 nt.(2) = 9 nt.(3) = 29 nt.(4) = 58 ---
5.4.1 Important Differences Between Nested Tables and Arrays
Conceptually, a nested table is like a one-dimensional array with an arbitrary number of elements. However, a nested table differs from an array in these important ways:
-
An array has a declared number of elements, but a nested table does not. The size of a nested table can increase dynamically.
-
An array is always dense. A nested array is dense initially, but it can become sparse, because you can delete elements from it.
Figure 5-2 shows the important differences between a nested table and an array.
5.4.2 Appropriate Uses for Nested Tables
A nested table is appropriate when:
-
The number of elements is not set.
-
Index values are not consecutive.
-
You must delete or update some elements, but not all elements simultaneously.
Nested table data is stored in a separate store table, a system-generated database table. When you access a nested table, the database joins the nested table with its store table. This makes nested tables suitable for queries and updates that affect only some elements of the collection.
-
You would create a separate lookup table, with multiple entries for each row of the main table, and access it through join queries.
5.5 Collection Constructors
A collection constructor (constructor) is a system-defined function with the same name as a collection type, which returns a collection of that type.
Note:
This topic applies only to varrays and nested tables. Associative arrays do not have constructors. In this topic, collection means varray or nested table.
The syntax of a constructor invocation is:
collection_type ( [ value [, value ]... ] )
If the parameter list is empty, the constructor returns an empty collection. Otherwise, the constructor returns a collection that contains the specified values. For semantic details, see "collection_constructor".
You can assign the returned collection to a collection variable (of the same type) in the variable declaration and in the executable part of a block.
Example 5-7 Initializing Collection (Varray) Variable to Empty
This example invokes a constructor twice: to initialize the varray variable team
to empty in its declaration, and to give it new values in the executable part of the block. The procedure print_team
shows the initial and final values of team
. To determine when team
is empty, print_team
uses the collection method COUNT
, described in "Collection Methods". (For an example of a procedure that prints a varray that might be null, see Example 5-24.)
Live SQL:
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DECLARE TYPE Foursome IS VARRAY(4) OF VARCHAR2(15); team Foursome := Foursome(); -- initialize to empty PROCEDURE print_team (heading VARCHAR2) IS BEGIN DBMS_OUTPUT.PUT_LINE(heading); IF team.COUNT = 0 THEN DBMS_OUTPUT.PUT_LINE('Empty'); ELSE FOR i IN 1..4 LOOP DBMS_OUTPUT.PUT_LINE(i || '.' || team(i)); END LOOP; END IF; DBMS_OUTPUT.PUT_LINE('---'); END; BEGIN print_team('Team:'); team := Foursome('John', 'Mary', 'Alberto', 'Juanita'); print_team('Team:'); END; /
Result:
Team: Empty --- Team: 1.John 2.Mary 3.Alberto 4.Juanita ---
5.6 Assigning Values to Collection Variables
You can assign a value to a collection variable in these ways:
-
Invoke a constructor to create a collection and assign it to the collection variable.
-
Use the assignment statement to assign it the value of another existing collection variable.
-
Pass it to a subprogram as an
OUT
orIN
OUT
parameter, and then assign the value inside the subprogram.
To assign a value to a scalar element of a collection variable, reference the element as collection_variable_name
(
index
)
and assign it a value.
Topics
See Also:
-
"Assignment Statement" syntax diagram
-
"Assigning Values to Variables" for instructions on how to assign a value to a scalar element of a collection variable
5.6.1 Data Type Compatibility
You can assign a collection to a collection variable only if they have the same data type. Having the same element type is not enough.
Example 5-8 Data Type Compatibility for Collection Assignment
In this example, VARRAY
types triplet
and trio
have the same element type, VARCHAR(15)
. Collection variables group1
and group2
have the same data type, triplet
, but collection variable group3
has the data type trio
. The assignment of group1
to group2
succeeds, but the assignment of group1
to group3
fails.
Live SQL:
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DECLARE TYPE triplet IS VARRAY(3) OF VARCHAR2(15); TYPE trio IS VARRAY(3) OF VARCHAR2(15); group1 triplet := triplet('Jones', 'Wong', 'Marceau'); group2 triplet; group3 trio; BEGIN group2 := group1; -- succeeds group3 := group1; -- fails END; /
Result:
ORA-06550: line 10, column 13: PLS-00382: expression is of wrong type
5.6.2 Assigning Null Values to Varray or Nested Table Variables
To a varray or nested table variable, you can assign the value NULL
or a null collection of the same data type. Either assignment makes the variable null.
Example 5-9 initializes the nested table variable dept_names
to a non-null value; assigns a null collection to it, making it null; and re-initializes it to a different non-null value.
Example 5-9 Assigning Null Value to Nested Table Variable
Live SQL:
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DECLARE
TYPE dnames_tab IS TABLE OF VARCHAR2(30);
dept_names dnames_tab := dnames_tab(
'Shipping','Sales','Finance','Payroll'); -- Initialized to non-null value
empty_set dnames_tab; -- Not initialized, therefore null
PROCEDURE print_dept_names_status IS
BEGIN
IF dept_names IS NULL THEN
DBMS_OUTPUT.PUT_LINE('dept_names is null.');
ELSE
DBMS_OUTPUT.PUT_LINE('dept_names is not null.');
END IF;
END print_dept_names_status;
BEGIN
print_dept_names_status;
dept_names := empty_set; -- Assign null collection to dept_names.
print_dept_names_status;
dept_names := dnames_tab (
'Shipping','Sales','Finance','Payroll'); -- Re-initialize dept_names
print_dept_names_status;
END;
/
Result:
dept_names is not null.
dept_names is null.
dept_names is not null.
5.6.3 Assigning Set Operation Results to Nested Table Variables
To a nested table variable, you can assign the result of a SQL MULTISET
operation or SQL SET
function invocation.
The SQL MULTISET
operators combine two nested tables into a single nested table. The elements of the two nested tables must have comparable data types. For information about the MULTISET
operators, see Oracle Database SQL Language Reference.
The SQL SET
function takes a nested table argument and returns a nested table of the same data type whose elements are distinct (the function eliminates duplicate elements). For information about the SET
function, see Oracle Database SQL Language Reference.
Example 5-10 Assigning Set Operation Results to Nested Table Variable
This example assigns the results of several MULTISET
operations and one SET
function invocation of the nested table variable answer
, using the procedure print_nested_table
to print answer
after each assignment. The procedure uses the collection methods FIRST
and LAST
, described in "Collection Methods".
Live SQL:
You can view and run this example on Oracle Live SQL at Assigning Set Operation Results to Nested Table Variable
DECLARE TYPE nested_typ IS TABLE OF NUMBER; nt1 nested_typ := nested_typ(1,2,3); nt2 nested_typ := nested_typ(3,2,1); nt3 nested_typ := nested_typ(2,3,1,3); nt4 nested_typ := nested_typ(1,2,4); answer nested_typ; PROCEDURE print_nested_table (nt nested_typ) IS output VARCHAR2(128); BEGIN IF nt IS NULL THEN DBMS_OUTPUT.PUT_LINE('Result: null set'); ELSIF nt.COUNT = 0 THEN DBMS_OUTPUT.PUT_LINE('Result: empty set'); ELSE FOR i IN nt.FIRST .. nt.LAST LOOP -- For first to last element output := output || nt(i) || ' '; END LOOP; DBMS_OUTPUT.PUT_LINE('Result: ' || output); END IF; END print_nested_table; BEGIN answer := nt1 MULTISET UNION nt4; print_nested_table(answer); answer := nt1 MULTISET UNION nt3; print_nested_table(answer); answer := nt1 MULTISET UNION DISTINCT nt3; print_nested_table(answer); answer := nt2 MULTISET INTERSECT nt3; print_nested_table(answer); answer := nt2 MULTISET INTERSECT DISTINCT nt3; print_nested_table(answer); answer := SET(nt3); print_nested_table(answer); answer := nt3 MULTISET EXCEPT nt2; print_nested_table(answer); answer := nt3 MULTISET EXCEPT DISTINCT nt2; print_nested_table(answer); END; /
Result:
Result: 1 2 3 1 2 4 Result: 1 2 3 2 3 1 3 Result: 1 2 3 Result: 3 2 1 Result: 3 2 1 Result: 2 3 1 Result: 3 Result: empty set
5.7 Multidimensional Collections
Although a collection has only one dimension, you can model a multidimensional collection with a collection whose elements are collections.
Example 5-11 Two-Dimensional Varray (Varray of Varrays)
In this example, nva
is a two-dimensional varray—a varray of varrays of integers.
Live SQL:
You can view and run this example on Oracle Live SQL at Two-Dimensional Varray (Varray of Varrays)
DECLARE TYPE t1 IS VARRAY(10) OF INTEGER; -- varray of integer va t1 := t1(2,3,5); TYPE nt1 IS VARRAY(10) OF t1; -- varray of varray of integer nva nt1 := nt1(va, t1(55,6,73), t1(2,4), va); i INTEGER; va1 t1; BEGIN i := nva(2)(3); DBMS_OUTPUT.PUT_LINE('i = ' || i); nva.EXTEND; nva(5) := t1(56, 32); -- replace inner varray elements nva(4) := t1(45,43,67,43345); -- replace an inner integer element nva(4)(4) := 1; -- replace 43345 with 1 nva(4).EXTEND; -- add element to 4th varray element nva(4)(5) := 89; -- store integer 89 there END; /
Result:
i = 73
Example 5-12 Nested Tables of Nested Tables and Varrays of Integers
In this example, ntb1
is a nested table of nested tables of strings, and ntb2
is a nested table of varrays of integers.
Live SQL:
You can view and run this example on Oracle Live SQL at Nested Tables of Nested Tables and Varrays of Integers
DECLARE TYPE tb1 IS TABLE OF VARCHAR2(20); -- nested table of strings vtb1 tb1 := tb1('one', 'three'); TYPE ntb1 IS TABLE OF tb1; -- nested table of nested tables of strings vntb1 ntb1 := ntb1(vtb1); TYPE tv1 IS VARRAY(10) OF INTEGER; -- varray of integers TYPE ntb2 IS TABLE OF tv1; -- nested table of varrays of integers vntb2 ntb2 := ntb2(tv1(3,5), tv1(5,7,3)); BEGIN vntb1.EXTEND; vntb1(2) := vntb1(1); vntb1.DELETE(1); -- delete first element of vntb1 vntb1(2).DELETE(1); -- delete first string from second table in nested table END; /
Example 5-13 Nested Tables of Associative Arrays and Varrays of Strings
In this example, aa1
is an associative array of associative arrays, and ntb2
is a nested table of varrays of strings.
Live SQL:
You can view and run this example on Oracle Live SQL at Nested Tables of Associative Arrays and Varrays of Strings
DECLARE TYPE tb1 IS TABLE OF INTEGER INDEX BY PLS_INTEGER; -- associative arrays v4 tb1; v5 tb1; TYPE aa1 IS TABLE OF tb1 INDEX BY PLS_INTEGER; -- associative array of v2 aa1; -- associative arrays TYPE va1 IS VARRAY(10) OF VARCHAR2(20); -- varray of strings v1 va1 := va1('hello', 'world'); TYPE ntb2 IS TABLE OF va1 INDEX BY PLS_INTEGER; -- associative array of varrays v3 ntb2; BEGIN v4(1) := 34; -- populate associative array v4(2) := 46456; v4(456) := 343; v2(23) := v4; -- populate associative array of associative arrays v3(34) := va1(33, 456, 656, 343); -- populate associative array varrays v2(35) := v5; -- assign empty associative array to v2(35) v2(35)(2) := 78; END; /
5.8 Collection Comparisons
To determine if one collection variable is less than another (for example), you must define what less than means in that context and write a function that returns TRUE
or FALSE
.
You cannot compare associative array variables to the value NULL
or to each other.
Except for Comparing Nested Tables for Equality and Inequality, you cannot natively compare two collection variables with relational operators. This restriction also applies to implicit comparisons. For example, a collection variable cannot appear in a DISTINCT
, GROUP
BY
, or ORDER
BY
clause.
Topics
See Also:
-
PL/SQL Subprograms for information about writing functions
5.8.1 Comparing Varray and Nested Table Variables to NULL
Use the IS[NOT] NULL
operator when comparing to the NULL value.
You can compare varray and nested table variables to the value NULL
with the "IS [NOT] NULL Operator", but not with the relational operators equal (=
) and not equal (<>
, !=
, ~=
, or ^=
).
Example 5-14 Comparing Varray and Nested Table Variables to NULL
This example compares a varray variable and a nested table variable to NULL
correctly.
Live SQL:
You can view and run this example on Oracle Live SQL at Comparing Varray and Nested Table Variables to NULL
DECLARE TYPE Foursome IS VARRAY(4) OF VARCHAR2(15); -- VARRAY type team Foursome; -- varray variable TYPE Roster IS TABLE OF VARCHAR2(15); -- nested table type names Roster := Roster('Adams', 'Patel'); -- nested table variable BEGIN IF team IS NULL THEN DBMS_OUTPUT.PUT_LINE('team IS NULL'); ELSE DBMS_OUTPUT.PUT_LINE('team IS NOT NULL'); END IF; IF names IS NOT NULL THEN DBMS_OUTPUT.PUT_LINE('names IS NOT NULL'); ELSE DBMS_OUTPUT.PUT_LINE('names IS NULL'); END IF; END; /
Result:
team IS NULL names IS NOT NULL
5.8.2 Comparing Nested Tables for Equality and Inequality
Two nested table variables are equal if and only if they have the same set of elements (in any order).
If two nested table variables have the same nested table type, and that nested table type does not have elements of a record type, then you can compare the two variables for equality or inequality with the relational operators equal (=
) and not equal (<>
, !=
, ~=
, ^=
).
See Also:
Example 5-15 Comparing Nested Tables for Equality and Inequality
This example compares nested table variables for equality and inequality with relational operators.
Live SQL:
You can view and run this example on Oracle Live SQL at Comparing Nested Tables for Equality and Inequality
DECLARE TYPE dnames_tab IS TABLE OF VARCHAR2(30); -- element type is not record type dept_names1 dnames_tab := dnames_tab('Shipping','Sales','Finance','Payroll'); dept_names2 dnames_tab := dnames_tab('Sales','Finance','Shipping','Payroll'); dept_names3 dnames_tab := dnames_tab('Sales','Finance','Payroll'); BEGIN IF dept_names1 = dept_names2 THEN DBMS_OUTPUT.PUT_LINE('dept_names1 = dept_names2'); END IF; IF dept_names2 != dept_names3 THEN DBMS_OUTPUT.PUT_LINE('dept_names2 != dept_names3'); END IF; END; /
Result:
dept_names1 = dept_names2 dept_names2 != dept_names3
5.8.3 Comparing Nested Tables with SQL Multiset Conditions
You can compare nested table variables, and test some of their properties, with SQL multiset conditions.
See Also:
-
Oracle Database SQL Language Reference for more information about multiset conditions
-
Oracle Database SQL Language Reference for details about
CARDINALITY
syntax -
Oracle Database SQL Language Referencefor details about
SET
syntax
Example 5-16 Comparing Nested Tables with SQL Multiset Conditions
This example uses the SQL multiset conditions and two SQL functions that take nested table variable arguments, CARDINALITY
and SET
.
Live SQL:
You can view and run this example on Oracle Live SQL at Comparing Nested Tables with SQL Multiset Conditions
DECLARE TYPE nested_typ IS TABLE OF NUMBER; nt1 nested_typ := nested_typ(1,2,3); nt2 nested_typ := nested_typ(3,2,1); nt3 nested_typ := nested_typ(2,3,1,3); nt4 nested_typ := nested_typ(1,2,4); PROCEDURE testify ( truth BOOLEAN := NULL, quantity NUMBER := NULL ) IS BEGIN IF truth IS NOT NULL THEN DBMS_OUTPUT.PUT_LINE ( CASE truth WHEN TRUE THEN 'True' WHEN FALSE THEN 'False' END ); END IF; IF quantity IS NOT NULL THEN DBMS_OUTPUT.PUT_LINE(quantity); END IF; END; BEGIN testify(truth => (nt1 IN (nt2,nt3,nt4))); -- condition testify(truth => (nt1 SUBMULTISET OF nt3)); -- condition testify(truth => (nt1 NOT SUBMULTISET OF nt4)); -- condition testify(truth => (4 MEMBER OF nt1)); -- condition testify(truth => (nt3 IS A SET)); -- condition testify(truth => (nt3 IS NOT A SET)); -- condition testify(truth => (nt1 IS EMPTY)); -- condition testify(quantity => (CARDINALITY(nt3))); -- function testify(quantity => (CARDINALITY(SET(nt3)))); -- 2 functions END; /
Result:
True True True False False True False 4 3
5.9 Collection Methods
A collection method is a PL/SQL subprogram—either a function that returns information about a collection or a procedure that operates on a collection. Collection methods make collections easier to use and your applications easier to maintain.
Table 5-2 summarizes the collection methods.
Note:
With a null collection, EXISTS
is the only collection method that does not raise the predefined exception COLLECTION_IS_NULL
.
Table 5-2 Collection Methods
Method | Type | Description |
---|---|---|
|
Procedure |
Deletes elements from collection. |
|
Procedure |
Deletes elements from end of varray or nested table. |
|
Procedure |
Adds elements to end of varray or nested table. |
|
Function |
Returns |
|
Function |
Returns first index in collection. |
|
Function |
Returns last index in collection. |
|
Function |
Returns number of elements in collection. |
|
Function |
Returns maximum number of elements that collection can have. |
|
Function |
Returns index that precedes specified index. |
|
Function |
Returns index that succeeds specified index. |
The basic syntax of a collection method invocation is:
collection_name.method
For detailed syntax, see "Collection Method Invocation".
A collection method invocation can appear anywhere that an invocation of a PL/SQL subprogram of its type (function or procedure) can appear, except in a SQL statement. (For general information about PL/SQL subprograms, see PL/SQL Subprograms.)
In a subprogram, a collection parameter assumes the properties of the argument bound to it. You can apply collection methods to such parameters. For varray parameters, the value of LIMIT
is always derived from the parameter type definition, regardless of the parameter mode.
Topics
5.9.1 DELETE Collection Method
DELETE
is a procedure that deletes elements from a collection.
This method has these forms:
-
DELETE
deletes all elements from a collection of any type.This operation immediately frees the memory allocated to the deleted elements.
-
From an associative array or nested table (but not a varray):
-
DELETE(
n
)
deletes the element whose index is n, if that element exists; otherwise, it does nothing. -
DELETE(
m,n
)
deletes all elements whose indexes are in the range m..n, if both m and n exist and m <= n; otherwise, it does nothing.
For these two forms of
DELETE
, PL/SQL keeps placeholders for the deleted elements. Therefore, the deleted elements are included in the internal size of the collection, and you can restore a deleted element by assigning a valid value to it. -
Example 5-17 DELETE Method with Nested Table
This example declares a nested table variable, initializing it with six elements; deletes and then restores the second element; deletes a range of elements and then restores one of them; and then deletes all elements. The restored elements occupy the same memory as the corresponding deleted elements. The procedure print_nt
prints the nested table variable after initialization and after each DELETE
operation. The type nt_type
and procedure print_nt
are defined in Example 5-6.
DECLARE nt nt_type := nt_type(11, 22, 33, 44, 55, 66); BEGIN print_nt(nt); nt.DELETE(2); -- Delete second element print_nt(nt); nt(2) := 2222; -- Restore second element print_nt(nt); nt.DELETE(2, 4); -- Delete range of elements print_nt(nt); nt(3) := 3333; -- Restore third element print_nt(nt); nt.DELETE; -- Delete all elements print_nt(nt); END; /
Result:
nt.(1) = 11 nt.(2) = 22 nt.(3) = 33 nt.(4) = 44 nt.(5) = 55 nt.(6) = 66 --- nt.(1) = 11 nt.(3) = 33 nt.(4) = 44 nt.(5) = 55 nt.(6) = 66 --- nt.(1) = 11 nt.(2) = 2222 nt.(3) = 33 nt.(4) = 44 nt.(5) = 55 nt.(6) = 66 --- nt.(1) = 11 nt.(5) = 55 nt.(6) = 66 --- nt.(1) = 11 nt.(3) = 3333 nt.(5) = 55 nt.(6) = 66 --- nt is empty ---
Example 5-18 DELETE Method with Associative Array Indexed by String
This example populates an associative array indexed by string and deletes all elements, which frees the memory allocated to them. Next, the example replaces the deleted elements—that is, adds new elements that have the same indexes as the deleted elements. The new replacement elements do not occupy the same memory as the corresponding deleted elements. Finally, the example deletes one element and then a range of elements. The procedure print_aa_str
shows the effects of the operations.
DECLARE TYPE aa_type_str IS TABLE OF INTEGER INDEX BY VARCHAR2(10); aa_str aa_type_str; PROCEDURE print_aa_str IS i VARCHAR2(10); BEGIN i := aa_str.FIRST; IF i IS NULL THEN DBMS_OUTPUT.PUT_LINE('aa_str is empty'); ELSE WHILE i IS NOT NULL LOOP DBMS_OUTPUT.PUT('aa_str.(' || i || ') = '); DBMS_OUTPUT.PUT_LINE(NVL(TO_CHAR(aa_str(i)), 'NULL')); i := aa_str.NEXT(i); END LOOP; END IF; DBMS_OUTPUT.PUT_LINE('---'); END print_aa_str; BEGIN aa_str('M') := 13; aa_str('Z') := 26; aa_str('C') := 3; print_aa_str; aa_str.DELETE; -- Delete all elements print_aa_str; aa_str('M') := 13; -- Replace deleted element with same value aa_str('Z') := 260; -- Replace deleted element with new value aa_str('C') := 30; -- Replace deleted element with new value aa_str('W') := 23; -- Add new element aa_str('J') := 10; -- Add new element aa_str('N') := 14; -- Add new element aa_str('P') := 16; -- Add new element aa_str('W') := 23; -- Add new element aa_str('J') := 10; -- Add new element print_aa_str; aa_str.DELETE('C'); -- Delete one element print_aa_str; aa_str.DELETE('N','W'); -- Delete range of elements print_aa_str; aa_str.DELETE('Z','M'); -- Does nothing print_aa_str; END; /
Result:
aa_str.(C) = 3 aa_str.(M) = 13 aa_str.(Z) = 26 --- aa_str is empty --- aa_str.(C) = 30 aa_str.(J) = 10 aa_str.(M) = 13 aa_str.(N) = 14 aa_str.(P) = 16 aa_str.(W) = 23 aa_str.(Z) = 260 --- aa_str.(J) = 10 aa_str.(M) = 13 aa_str.(N) = 14 aa_str.(P) = 16 aa_str.(W) = 23 aa_str.(Z) = 260 --- aa_str.(J) = 10 aa_str.(M) = 13 aa_str.(Z) = 260 --- aa_str.(J) = 10 aa_str.(M) = 13 aa_str.(Z) = 260 ---
5.9.2 TRIM Collection Method
TRIM
is a procedure that deletes elements from the end of a varray or nested table.
This method has these forms:
-
TRIM
removes one element from the end of the collection, if the collection has at least one element; otherwise, it raises the predefined exceptionSUBSCRIPT_BEYOND_COUNT
. -
TRIM(
n
)
removes n elements from the end of the collection, if there are at least n elements at the end; otherwise, it raises the predefined exceptionSUBSCRIPT_BEYOND_COUNT
.
TRIM
operates on the internal size of a collection. That is, if DELETE
deletes an element but keeps a placeholder for it, then TRIM
considers the element to exist. Therefore, TRIM
can delete a deleted element.
PL/SQL does not keep placeholders for trimmed elements. Therefore, trimmed elements are not included in the internal size of the collection, and you cannot restore a trimmed element by assigning a valid value to it.
Caution:
Do not depend on interaction between TRIM
and DELETE
. Treat nested tables like either fixed-size arrays (and use only DELETE
) or stacks (and use only TRIM
and EXTEND
).
Example 5-19 TRIM Method with Nested Table
This example declares a nested table variable, initializing it with six elements; trims the last element; deletes the fourth element; and then trims the last two elements—one of which is the deleted fourth element. The procedure print_nt
prints the nested table variable after initialization and after the TRIM
and DELETE
operations. The type nt_type
and procedure print_nt
are defined in Example 5-6.
DECLARE nt nt_type := nt_type(11, 22, 33, 44, 55, 66); BEGIN print_nt(nt); nt.TRIM; -- Trim last element print_nt(nt); nt.DELETE(4); -- Delete fourth element print_nt(nt); nt.TRIM(2); -- Trim last two elements print_nt(nt); END; /
Result:
nt.(1) = 11 nt.(2) = 22 nt.(3) = 33 nt.(4) = 44 nt.(5) = 55 nt.(6) = 66 --- nt.(1) = 11 nt.(2) = 22 nt.(3) = 33 nt.(4) = 44 nt.(5) = 55 --- nt.(1) = 11 nt.(2) = 22 nt.(3) = 33 nt.(5) = 55 --- nt.(1) = 11 nt.(2) = 22 nt.(3) = 33 ---
5.9.3 EXTEND Collection Method
EXTEND
is a procedure that adds elements to the end of a varray or nested table.
The collection can be empty, but not null. (To make a collection empty or add elements to a null collection, use a constructor. For more information, see "Collection Constructors".)
The EXTEND
method has these forms:
-
EXTEND
appends one null element to the collection. -
EXTEND(
n
)
appends n null elements to the collection. -
EXTEND(
n
,i
)
appends n copies of the ith element to the collection.Note:
EXTEND(
n
,i
)
is the only form that you can use for a collection whose elements have theNOT
NULL
constraint.
EXTEND
operates on the internal size of a collection. That is, if DELETE
deletes an element but keeps a placeholder for it, then EXTEND
considers the element to exist.
Example 5-20 EXTEND Method with Nested Table
This example declares a nested table variable, initializing it with three elements; appends two copies of the first element; deletes the fifth (last) element; and then appends one null element. Because EXTEND
considers the deleted fifth element to exist, the appended null element is the sixth element. The procedure print_nt
prints the nested table variable after initialization and after the EXTEND
and DELETE
operations. The type nt_type
and procedure print_nt
are defined in Example 5-6.
DECLARE nt nt_type := nt_type(11, 22, 33); BEGIN print_nt(nt); nt.EXTEND(2,1); -- Append two copies of first element print_nt(nt); nt.DELETE(5); -- Delete fifth element print_nt(nt); nt.EXTEND; -- Append one null element print_nt(nt); END; /
Result:
nt.(1) = 11
nt.(2) = 22
nt.(3) = 33
---
nt.(1) = 11
nt.(2) = 22
nt.(3) = 33
nt.(4) = 11
nt.(5) = 11
---
nt.(1) = 11
nt.(2) = 22
nt.(3) = 33
nt.(4) = 11
---
nt.(1) = 11
nt.(2) = 22
nt.(3) = 33
nt.(4) = 11
nt.(6) = NULL
---
5.9.4 EXISTS Collection Method
EXISTS
is a function that tells you whether the specified element of a varray or nested table exists.
EXISTS(
n
)
returns TRUE
if the nth element of the collection exists and FALSE
otherwise. If n is out of range, EXISTS
returns FALSE
instead of raising the predefined exception SUBSCRIPT_OUTSIDE_LIMIT
.
For a deleted element, EXISTS(
n
)
returns FALSE
, even if DELETE
kept a placeholder for it.
Example 5-21 EXISTS Method with Nested Table
This example initializes a nested table with four elements, deletes the second element, and prints either the value or status of elements 1 through 6.
DECLARE TYPE NumList IS TABLE OF INTEGER; n NumList := NumList(1,3,5,7); BEGIN n.DELETE(2); -- Delete second element FOR i IN 1..6 LOOP IF n.EXISTS(i) THEN DBMS_OUTPUT.PUT_LINE('n(' || i || ') = ' || n(i)); ELSE DBMS_OUTPUT.PUT_LINE('n(' || i || ') does not exist'); END IF; END LOOP; END; /
Result:
n(1) = 1 n(2) does not exist n(3) = 5 n(4) = 7 n(5) does not exist n(6) does not exist
5.9.5 FIRST and LAST Collection Methods
FIRST
and LAST
are functions.
If the collection has at least one element, FIRST
and LAST
return the indexes of the first and last elements, respectively (ignoring deleted elements, even if DELETE
kept placeholders for them). If the collection has only one element, FIRST
and LAST
return the same index. If the collection is empty, FIRST
and LAST
return NULL
.
Topics
5.9.5.1 FIRST and LAST Methods for Associative Array
For an associative array indexed by PLS_INTEGER
, the first and last elements are those with the smallest and largest indexes, respectively. For an associative array indexed by string, the first and last elements are those with the lowest and highest key values, respectively.
Key values are in sorted order (for more information, see "NLS Parameter Values Affect Associative Arrays Indexed by String").
Example 5-22 FIRST and LAST Values for Associative Array Indexed by PLS_INTEGER
This example shows the values of FIRST
and LAST
for an associative array indexed by PLS_INTEGER
, deletes the first and last elements, and shows the values of FIRST
and LAST
again.
DECLARE TYPE aa_type_int IS TABLE OF INTEGER INDEX BY PLS_INTEGER; aa_int aa_type_int; PROCEDURE print_first_and_last IS BEGIN DBMS_OUTPUT.PUT_LINE('FIRST = ' || aa_int.FIRST); DBMS_OUTPUT.PUT_LINE('LAST = ' || aa_int.LAST); END print_first_and_last; BEGIN aa_int(1) := 3; aa_int(2) := 6; aa_int(3) := 9; aa_int(4) := 12; DBMS_OUTPUT.PUT_LINE('Before deletions:'); print_first_and_last; aa_int.DELETE(1); aa_int.DELETE(4); DBMS_OUTPUT.PUT_LINE('After deletions:'); print_first_and_last; END; /
Result:
Before deletions: FIRST = 1 LAST = 4 After deletions: FIRST = 2 LAST = 3
Example 5-23 FIRST and LAST Values for Associative Array Indexed by String
This example shows the values of FIRST
and LAST
for an associative array indexed by string, deletes the first and last elements, and shows the values of FIRST
and LAST
again.
DECLARE TYPE aa_type_str IS TABLE OF INTEGER INDEX BY VARCHAR2(10); aa_str aa_type_str; PROCEDURE print_first_and_last IS BEGIN DBMS_OUTPUT.PUT_LINE('FIRST = ' || aa_str.FIRST); DBMS_OUTPUT.PUT_LINE('LAST = ' || aa_str.LAST); END print_first_and_last; BEGIN aa_str('Z') := 26; aa_str('A') := 1; aa_str('K') := 11; aa_str('R') := 18; DBMS_OUTPUT.PUT_LINE('Before deletions:'); print_first_and_last; aa_str.DELETE('A'); aa_str.DELETE('Z'); DBMS_OUTPUT.PUT_LINE('After deletions:'); print_first_and_last; END; /
Result:
Before deletions: FIRST = A LAST = Z After deletions: FIRST = K LAST = R
5.9.5.2 FIRST and LAST Methods for Varray
For a varray that is not empty, FIRST
always returns 1. For every varray, LAST
always equals COUNT
.
Example 5-24 Printing Varray with FIRST and LAST in FOR LOOP
This example prints the varray team
using a FOR
LOOP
statement with the bounds team
.FIRST
and team
.LAST
. Because a varray is always dense, team(i)
inside the loop always exists.
DECLARE TYPE team_type IS VARRAY(4) OF VARCHAR2(15); team team_type; PROCEDURE print_team (heading VARCHAR2) IS BEGIN DBMS_OUTPUT.PUT_LINE(heading); IF team IS NULL THEN DBMS_OUTPUT.PUT_LINE('Does not exist'); ELSIF team.FIRST IS NULL THEN DBMS_OUTPUT.PUT_LINE('Has no members'); ELSE FOR i IN team.FIRST..team.LAST LOOP DBMS_OUTPUT.PUT_LINE(i || '. ' || team(i)); END LOOP; END IF; DBMS_OUTPUT.PUT_LINE('---'); END; BEGIN print_team('Team Status:'); team := team_type(); -- Team is funded, but nobody is on it. print_team('Team Status:'); team := team_type('John', 'Mary'); -- Put 2 members on team. print_team('Initial Team:'); team := team_type('Arun', 'Amitha', 'Allan', 'Mae'); -- Change team. print_team('New Team:'); END; /
Result:
Team Status: Does not exist --- Team Status: Has no members --- Initial Team: 1. John 2. Mary --- New Team: 1. Arun 2. Amitha 3. Allan 4. Mae ---
Related Topic
5.9.5.3 FIRST and LAST Methods for Nested Table
For a nested table, LAST
equals COUNT
unless you delete elements from its middle, in which case LAST
is larger than COUNT
.
Example 5-25 Printing Nested Table with FIRST and LAST in FOR LOOP
This example prints the nested table team
using a FOR
LOOP
statement with the bounds team
.FIRST
and team
.LAST
. Because a nested table can be sparse, the FOR
LOOP
statement prints team(i)
only if team
.EXISTS(i)
is TRUE
.
DECLARE TYPE team_type IS TABLE OF VARCHAR2(15); team team_type; PROCEDURE print_team (heading VARCHAR2) IS BEGIN DBMS_OUTPUT.PUT_LINE(heading); IF team IS NULL THEN DBMS_OUTPUT.PUT_LINE('Does not exist'); ELSIF team.FIRST IS NULL THEN DBMS_OUTPUT.PUT_LINE('Has no members'); ELSE FOR i IN team.FIRST..team.LAST LOOP DBMS_OUTPUT.PUT(i || '. '); IF team.EXISTS(i) THEN DBMS_OUTPUT.PUT_LINE(team(i)); ELSE DBMS_OUTPUT.PUT_LINE('(to be hired)'); END IF; END LOOP; END IF; DBMS_OUTPUT.PUT_LINE('---'); END; BEGIN print_team('Team Status:'); team := team_type(); -- Team is funded, but nobody is on it. print_team('Team Status:'); team := team_type('Arun', 'Amitha', 'Allan', 'Mae'); -- Add members. print_team('Initial Team:'); team.DELETE(2,3); -- Remove 2nd and 3rd members. print_team('Current Team:'); END; /
Result:
Team Status: Does not exist --- Team Status: Has no members --- Initial Team: 1. Arun 2. Amitha 3. Allan 4. Mae --- Current Team: 1. Arun 2. (to be hired) 3. (to be hired) 4. Mae ---
Related Topic
5.9.6 COUNT Collection Method
COUNT
is a function that returns the number of elements in the collection (ignoring deleted elements, even if DELETE
kept placeholders for them).
Topics
5.9.6.1 COUNT Method for Varray
For a varray, COUNT
always equals LAST
. If you increase or decrease the size of a varray (with the EXTEND
or TRIM
method), the value of COUNT
changes.
Example 5-26 COUNT and LAST Values for Varray
This example shows the values of COUNT
and LAST
for a varray after initialization with four elements, after EXTEND(3)
, and after TRIM(5)
.
DECLARE TYPE NumList IS VARRAY(10) OF INTEGER; n NumList := NumList(1,3,5,7); PROCEDURE print_count_and_last IS BEGIN DBMS_OUTPUT.PUT('n.COUNT = ' || n.COUNT || ', '); DBMS_OUTPUT.PUT_LINE('n.LAST = ' || n.LAST); END print_count_and_last; BEGIN print_count_and_last; n.EXTEND(3); print_count_and_last; n.TRIM(5); print_count_and_last; END; /
Result:
n.COUNT = 4, n.LAST = 4 n.COUNT = 7, n.LAST = 7 n.COUNT = 2, n.LAST = 2
5.9.6.2 COUNT Method for Nested Table
For a nested table, COUNT
equals LAST
unless you delete elements from the middle of the nested table, in which case COUNT
is smaller than LAST
.
Example 5-27 COUNT and LAST Values for Nested Table
This example shows the values of COUNT
and LAST
for a nested table after initialization with four elements, after deleting the third element, and after adding two null elements to the end. Finally, the example prints the status of elements 1 through 8.
DECLARE TYPE NumList IS TABLE OF INTEGER; n NumList := NumList(1,3,5,7); PROCEDURE print_count_and_last IS BEGIN DBMS_OUTPUT.PUT('n.COUNT = ' || n.COUNT || ', '); DBMS_OUTPUT.PUT_LINE('n.LAST = ' || n.LAST); END print_count_and_last; BEGIN print_count_and_last; n.DELETE(3); -- Delete third element print_count_and_last; n.EXTEND(2); -- Add two null elements to end print_count_and_last; FOR i IN 1..8 LOOP IF n.EXISTS(i) THEN IF n(i) IS NOT NULL THEN DBMS_OUTPUT.PUT_LINE('n(' || i || ') = ' || n(i)); ELSE DBMS_OUTPUT.PUT_LINE('n(' || i || ') = NULL'); END IF; ELSE DBMS_OUTPUT.PUT_LINE('n(' || i || ') does not exist'); END IF; END LOOP; END; /
Result:
n.COUNT = 4, n.LAST = 4 n.COUNT = 3, n.LAST = 4 n.COUNT = 5, n.LAST = 6 n(1) = 1 n(2) = 3 n(3) does not exist n(4) = 7 n(5) = NULL n(6) = NULL n(7) does not exist n(8) does not exist
5.9.7 LIMIT Collection Method
LIMIT
is a function that returns the maximum number of elements that the collection can have. If the collection has no maximum number of elements, LIMIT
returns NULL
. Only a varray has a maximum size.
Example 5-28 LIMIT and COUNT Values for Different Collection Types
This example prints the values of LIMIT
and COUNT
for an associative array with four elements, a varray with two elements, and a nested table with three elements.
DECLARE TYPE aa_type IS TABLE OF INTEGER INDEX BY PLS_INTEGER; aa aa_type; -- associative array TYPE va_type IS VARRAY(4) OF INTEGER; va va_type := va_type(2,4); -- varray TYPE nt_type IS TABLE OF INTEGER; nt nt_type := nt_type(1,3,5); -- nested table BEGIN aa(1):=3; aa(2):=6; aa(3):=9; aa(4):= 12; DBMS_OUTPUT.PUT('aa.COUNT = '); DBMS_OUTPUT.PUT_LINE(NVL(TO_CHAR(aa.COUNT), 'NULL')); DBMS_OUTPUT.PUT('aa.LIMIT = '); DBMS_OUTPUT.PUT_LINE(NVL(TO_CHAR(aa.LIMIT), 'NULL')); DBMS_OUTPUT.PUT('va.COUNT = '); DBMS_OUTPUT.PUT_LINE(NVL(TO_CHAR(va.COUNT), 'NULL')); DBMS_OUTPUT.PUT('va.LIMIT = '); DBMS_OUTPUT.PUT_LINE(NVL(TO_CHAR(va.LIMIT), 'NULL')); DBMS_OUTPUT.PUT('nt.COUNT = '); DBMS_OUTPUT.PUT_LINE(NVL(TO_CHAR(nt.COUNT), 'NULL')); DBMS_OUTPUT.PUT('nt.LIMIT = '); DBMS_OUTPUT.PUT_LINE(NVL(TO_CHAR(nt.LIMIT), 'NULL')); END; /
Result:
aa.COUNT = 4 aa.LIMIT = NULL va.COUNT = 2 va.LIMIT = 4 nt.COUNT = 3 nt.LIMIT = NULL
5.9.8 PRIOR and NEXT Collection Methods
PRIOR
and NEXT
are functions that let you move backward and forward in the collection (ignoring deleted elements, even if DELETE
kept placeholders for them). These methods are useful for traversing sparse collections.
Given an index:
-
PRIOR
returns the index of the preceding existing element of the collection, if one exists. Otherwise,PRIOR
returnsNULL
.For any collection
c
,c.PRIOR(c.FIRST)
returnsNULL
. -
NEXT
returns the index of the succeeding existing element of the collection, if one exists. Otherwise,NEXT
returnsNULL
.For any collection
c
,c.NEXT(c.LAST)
returnsNULL
.
The given index need not exist. However, if the collection c
is a varray, and the index exceeds c.LIMIT
, then:
-
c.PRIOR(
index
)
returnsc.LAST
. -
c.NEXT(
index
)
returnsNULL
.
For example:
DECLARE TYPE Arr_Type IS VARRAY(10) OF NUMBER; v_Numbers Arr_Type := Arr_Type(); BEGIN v_Numbers.EXTEND(4); v_Numbers (1) := 10; v_Numbers (2) := 20; v_Numbers (3) := 30; v_Numbers (4) := 40; DBMS_OUTPUT.PUT_LINE(NVL(v_Numbers.prior (3400), -1)); DBMS_OUTPUT.PUT_LINE(NVL(v_Numbers.next (3400), -1)); END; /
Result:
4 -1
For an associative array indexed by string, the prior and next indexes are determined by key values, which are in sorted order (for more information, see "NLS Parameter Values Affect Associative Arrays Indexed by String"). Example 5-1 uses FIRST
, NEXT
, and a WHILE
LOOP
statement to print the elements of an associative array.
Example 5-29 PRIOR and NEXT Methods
This example initializes a nested table with six elements, deletes the fourth element, and then shows the values of PRIOR
and NEXT
for elements 1 through 7. Elements 4 and 7 do not exist. Element 2 exists, despite its null value.
DECLARE TYPE nt_type IS TABLE OF NUMBER; nt nt_type := nt_type(18, NULL, 36, 45, 54, 63); BEGIN nt.DELETE(4); DBMS_OUTPUT.PUT_LINE('nt(4) was deleted.'); FOR i IN 1..7 LOOP DBMS_OUTPUT.PUT('nt.PRIOR(' || i || ') = '); DBMS_OUTPUT.PUT_LINE(NVL(TO_CHAR(nt.PRIOR(i)), 'NULL')); DBMS_OUTPUT.PUT('nt.NEXT(' || i || ') = '); DBMS_OUTPUT.PUT_LINE(NVL(TO_CHAR(nt.NEXT(i)), 'NULL')); END LOOP; END; /
Result:
nt(4) was deleted. nt.PRIOR(1) = NULL nt.NEXT(1) = 2 nt.PRIOR(2) = 1 nt.NEXT(2) = 3 nt.PRIOR(3) = 2 nt.NEXT(3) = 5 nt.PRIOR(4) = 3 nt.NEXT(4) = 5 nt.PRIOR(5) = 3 nt.NEXT(5) = 6 nt.PRIOR(6) = 5 nt.NEXT(6) = NULL nt.PRIOR(7) = 6 nt.NEXT(7) = NULL
Example 5-30 Printing Elements of Sparse Nested Table
This example prints the elements of a sparse nested table from first to last, using FIRST
and NEXT
, and from last to first, using LAST
and PRIOR
.
DECLARE TYPE NumList IS TABLE OF NUMBER; n NumList := NumList(1, 2, NULL, NULL, 5, NULL, 7, 8, 9, NULL); idx INTEGER; BEGIN DBMS_OUTPUT.PUT_LINE('First to last:'); idx := n.FIRST; WHILE idx IS NOT NULL LOOP DBMS_OUTPUT.PUT('n(' || idx || ') = '); DBMS_OUTPUT.PUT_LINE(NVL(TO_CHAR(n(idx)), 'NULL')); idx := n.NEXT(idx); END LOOP; DBMS_OUTPUT.PUT_LINE('--------------'); DBMS_OUTPUT.PUT_LINE('Last to first:'); idx := n.LAST; WHILE idx IS NOT NULL LOOP DBMS_OUTPUT.PUT('n(' || idx || ') = '); DBMS_OUTPUT.PUT_LINE(NVL(TO_CHAR(n(idx)), 'NULL')); idx := n.PRIOR(idx); END LOOP; END; /
Result:
First to last: n(1) = 1 n(2) = 2 n(3) = NULL n(4) = NULL n(5) = 5 n(6) = NULL n(7) = 7 n(8) = 8 n(9) = 9 n(10) = NULL -------------- Last to first: n(10) = NULL n(9) = 9 n(8) = 8 n(7) = 7 n(6) = NULL n(5) = 5 n(4) = NULL n(3) = NULL n(2) = 2 n(1) = 1
5.10 Collection Types Defined in Package Specifications
A collection type defined in a package specification is incompatible with an identically defined local or standalone collection type.
Note:
The examples in this topic define packages and procedures, which are explained in PL/SQL Packages and PL/SQL Subprograms, respectively.
Example 5-31 Identically Defined Package and Local Collection Types
In this example, the package specification and the anonymous block define the collection type NumList
identically. The package defines a procedure, print_numlist
, which has a NumList
parameter. The anonymous block declares the variable n1
of the type pkg.NumList
(defined in the package) and the variable n2
of the type NumList
(defined in the block). The anonymous block can pass n1
to print_numlist
, but it cannot pass n2
to print_numlist
.
Live SQL:
You can view and run this example on Oracle Live SQL at Identically Defined Package and Local Collection Types
CREATE OR REPLACE PACKAGE pkg AS TYPE NumList IS TABLE OF NUMBER; PROCEDURE print_numlist (nums NumList); END pkg; / CREATE OR REPLACE PACKAGE BODY pkg AS PROCEDURE print_numlist (nums NumList) IS BEGIN FOR i IN nums.FIRST..nums.LAST LOOP DBMS_OUTPUT.PUT_LINE(nums(i)); END LOOP; END; END pkg; / DECLARE TYPE NumList IS TABLE OF NUMBER; -- local type identical to package type n1 pkg.NumList := pkg.NumList(2,4); -- package type n2 NumList := NumList(6,8); -- local type BEGIN pkg.print_numlist(n1); -- succeeds pkg.print_numlist(n2); -- fails END; /
Result:
pkg.print_numlist(n2); -- fails * ERROR at line 7: ORA-06550: line 7, column 3: PLS-00306: wrong number or types of arguments in call to 'PRINT_NUMLIST' ORA-06550: line 7, column 3: PL/SQL: Statement ignored
Example 5-32 Identically Defined Package and Standalone Collection Types
This example defines a standalone collection type NumList
that is identical to the collection type NumList
defined in the package specification in Example 5-31. The anonymous block declares the variable n1
of the type pkg.NumList
(defined in the package) and the variable n2
of the standalone type NumList
. The anonymous block can pass n1
to print_numlist
, but it cannot pass n2
to print_numlist
.
Live SQL:
You can view and run this example on Oracle Live SQL at Identically Defined Package and Standalone Collection Types
CREATE OR REPLACE TYPE NumList IS TABLE OF NUMBER; -- standalone collection type identical to package type / DECLARE n1 pkg.NumList := pkg.NumList(2,4); -- package type n2 NumList := NumList(6,8); -- standalone type BEGIN pkg.print_numlist(n1); -- succeeds pkg.print_numlist(n2); -- fails END; /
Result:
pkg.print_numlist(n2); -- fails * ERROR at line 7: ORA-06550: line 7, column 3: PLS-00306: wrong number or types of arguments in call to 'PRINT_NUMLIST' ORA-06550: line 7, column 3: PL/SQL: Statement ignored
5.11 Record Variables
You can create a record variable in any of these ways:
-
Define a
RECORD
type and then declare a variable of that type. -
Use
%ROWTYPE
to declare a record variable that represents either a full or partial row of a database table or view. -
Use
%TYPE
to declare a record variable of the same type as a previously declared record variable.
For syntax and semantics, see "Record Variable Declaration".
Topics
5.11.1 Initial Values of Record Variables
For a record variable of a RECORD
type, the initial value of each field is NULL
unless you specify a different initial value for it when you define the type.
For a record variable declared with %ROWTYPE
or %TYPE
, the initial value of each field is NULL
. The variable does not inherit the initial value of the referenced item.
5.11.2 Declaring Record Constants
When declaring a record constant, you must create a function that populates the record with its initial value and then invoke the function in the constant declaration.
Example 5-33 Declaring Record Constant
This example creates a function that populates the record with its initial value and then invoke the function in the constant declaration.
Live SQL:
You can view and run this example on Oracle Live SQL at Declaring Record Constant
CREATE OR REPLACE PACKAGE My_Types AUTHID CURRENT_USER IS TYPE My_Rec IS RECORD (a NUMBER, b NUMBER); FUNCTION Init_My_Rec RETURN My_Rec; END My_Types; / CREATE OR REPLACE PACKAGE BODY My_Types IS FUNCTION Init_My_Rec RETURN My_Rec IS Rec My_Rec; BEGIN Rec.a := 0; Rec.b := 1; RETURN Rec; END Init_My_Rec; END My_Types; / DECLARE r CONSTANT My_Types.My_Rec := My_Types.Init_My_Rec(); BEGIN DBMS_OUTPUT.PUT_LINE('r.a = ' || r.a); DBMS_OUTPUT.PUT_LINE('r.b = ' || r.b); END; /
Result:
r.a = 0 r.b = 1 PL/SQL procedure successfully completed.
5.11.3 RECORD Types
A RECORD
type defined in a PL/SQL block is a local type. It is available only in the block, and is stored in the database only if the block is in a standalone or package subprogram.
A RECORD
type defined in a package specification is a public item. You can reference it from outside the package by qualifying it with the package name (package_name.type_name
). It is stored in the database until you drop the package with the DROP
PACKAGE
statement.
You cannot create a RECORD
type at schema level. Therefore, a RECORD
type cannot be an ADT attribute data type.
To define a RECORD
type, specify its name and define its fields. To define a field, specify its name and data type. By default, the initial value of a field is NULL
. You can specify the NOT
NULL
constraint for a field, in which case you must also specify a non-NULL
initial value. Without the NOT
NULL
constraint, a non-NULL
initial value is optional.
A RECORD
type defined in a package specification is incompatible with an identically defined local RECORD
type.
See Also:
Example 5-34 RECORD Type Definition and Variable Declaration
This example defines a RECORD
type named DeptRecTyp
, specifying an initial value for each field. Then it declares a variable of that type named dept_rec
and prints its fields.
Live SQL:
You can view and run this example on Oracle Live SQL at RECORD Type Definition and Variable Declaration
DECLARE TYPE DeptRecTyp IS RECORD ( dept_id NUMBER(4) NOT NULL := 10, dept_name VARCHAR2(30) NOT NULL := 'Administration', mgr_id NUMBER(6) := 200, loc_id NUMBER(4) := 1700 ); dept_rec DeptRecTyp; BEGIN DBMS_OUTPUT.PUT_LINE('dept_id: ' || dept_rec.dept_id); DBMS_OUTPUT.PUT_LINE('dept_name: ' || dept_rec.dept_name); DBMS_OUTPUT.PUT_LINE('mgr_id: ' || dept_rec.mgr_id); DBMS_OUTPUT.PUT_LINE('loc_id: ' || dept_rec.loc_id); END; /
Result:
dept_id: 10 dept_name: Administration mgr_id: 200 loc_id: 1700
Example 5-35 RECORD Type with RECORD Field (Nested Record)
This example defines two RECORD
types, name_rec
and contact
. The type contact
has a field of type name_rec
.
Live SQL:
You can view and run this example on Oracle Live SQL at RECORD Type with RECORD Field (Nested Record)
DECLARE TYPE name_rec IS RECORD ( first employees.first_name%TYPE, last employees.last_name%TYPE ); TYPE contact IS RECORD ( name name_rec, -- nested record phone employees.phone_number%TYPE ); friend contact; BEGIN friend.name.first := 'John'; friend.name.last := 'Smith'; friend.phone := '1-650-555-1234'; DBMS_OUTPUT.PUT_LINE ( friend.name.first || ' ' || friend.name.last || ', ' || friend.phone ); END; /
Result:
John Smith, 1-650-555-1234
Example 5-36 RECORD Type with Varray Field
This defines a VARRAY
type, full_name
, and a RECORD
type, contact
. The type contact
has a field of type full_name
.
Live SQL:
You can view and run this example on Oracle Live SQL at RECORD Type with Varray Field
DECLARE TYPE full_name IS VARRAY(2) OF VARCHAR2(20); TYPE contact IS RECORD ( name full_name := full_name('John', 'Smith'), -- varray field phone employees.phone_number%TYPE ); friend contact; BEGIN friend.phone := '1-650-555-1234'; DBMS_OUTPUT.PUT_LINE ( friend.name(1) || ' ' || friend.name(2) || ', ' || friend.phone ); END; /
Result:
John Smith, 1-650-555-1234
Example 5-37 Identically Defined Package and Local RECORD Types
In this example, the package pkg
and the anonymous block define the RECORD
type rec_type
identically. The package defines a procedure, print_rec_type
, which has a rec_type
parameter. The anonymous block declares the variable r1
of the package type (pkg.rec_type
) and the variable r2
of the local type (rec_type
). The anonymous block can pass r1
to print_rec_type
, but it cannot pass r2
to print_rec_type
.
Live SQL:
You can view and run this example on Oracle Live SQL at Identically Defined Package and Local RECORD Types
CREATE OR REPLACE PACKAGE pkg AS TYPE rec_type IS RECORD ( -- package RECORD type f1 INTEGER, f2 VARCHAR2(4) ); PROCEDURE print_rec_type (rec rec_type); END pkg; / CREATE OR REPLACE PACKAGE BODY pkg AS PROCEDURE print_rec_type (rec rec_type) IS BEGIN DBMS_OUTPUT.PUT_LINE(rec.f1); DBMS_OUTPUT.PUT_LINE(rec.f2); END; END pkg; / DECLARE TYPE rec_type IS RECORD ( -- local RECORD type f1 INTEGER, f2 VARCHAR2(4) ); r1 pkg.rec_type; -- package type r2 rec_type; -- local type BEGIN r1.f1 := 10; r1.f2 := 'abcd'; r2.f1 := 25; r2.f2 := 'wxyz'; pkg.print_rec_type(r1); -- succeeds pkg.print_rec_type(r2); -- fails END; /
Result:
pkg.print_rec_type(r2); -- fails * ERROR at line 14: ORA-06550: line 14, column 3: PLS-00306: wrong number or types of arguments in call to 'PRINT_REC_TYPE'
5.11.4 Declaring Items using the %ROWTYPE Attribute
The %ROWTYPE
attribute lets you declare a record variable that represents either a full or partial row of a database table or view.
For the syntax and semantics details, see %ROWTYPE Attribute.
Topics
5.11.4.1 Declaring a Record Variable that Always Represents Full Row
To declare a record variable that always represents a full row of a database table or view, use this syntax:
variable_name table_or_view_name%ROWTYPE;
For every column of the table or view, the record has a field with the same name and data type.
See Also:
"%ROWTYPE Attribute" for more information about %ROWTYPE
Example 5-38 %ROWTYPE Variable Represents Full Database Table Row
This example declares a record variable that represents a row of the table departments
, assigns values to its fields, and prints them. Compare this example to Example 5-34.
Live SQL:
You can view and run this example on Oracle Live SQL at %ROWTYPE Variable Represents Full Database Table Row
DECLARE
dept_rec departments%ROWTYPE;
BEGIN
-- Assign values to fields:
dept_rec.department_id := 10;
dept_rec.department_name := 'Administration';
dept_rec.manager_id := 200;
dept_rec.location_id := 1700;
-- Print fields:
DBMS_OUTPUT.PUT_LINE('dept_id: ' || dept_rec.department_id);
DBMS_OUTPUT.PUT_LINE('dept_name: ' || dept_rec.department_name);
DBMS_OUTPUT.PUT_LINE('mgr_id: ' || dept_rec.manager_id);
DBMS_OUTPUT.PUT_LINE('loc_id: ' || dept_rec.location_id);
END;
/
Result:
dept_id: 10 dept_name: Administration mgr_id: 200 loc_id: 1700
Example 5-39 %ROWTYPE Variable Does Not Inherit Initial Values or Constraints
This example creates a table with two columns, each with an initial value and a NOT
NULL
constraint. Then it declares a record variable that represents a row of the table and prints its fields, showing that they did not inherit the initial values or NOT
NULL
constraints.
Live SQL:
You can view and run this example on Oracle Live SQL at %ROWTYPE Variable Does Not Inherit Initial Values or Constraints
DROP TABLE t1; CREATE TABLE t1 ( c1 INTEGER DEFAULT 0 NOT NULL, c2 INTEGER DEFAULT 1 NOT NULL ); DECLARE t1_row t1%ROWTYPE; BEGIN DBMS_OUTPUT.PUT('t1.c1 = '); DBMS_OUTPUT.PUT_LINE(NVL(TO_CHAR(t1_row.c1), 'NULL')); DBMS_OUTPUT.PUT('t1.c2 = '); print(t1_row.c2); DBMS_OUTPUT.PUT_LINE(NVL(TO_CHAR(t1_row.c2), 'NULL')); END; /
Result:
t1.c1 = NULL t1.c2 = NULL
5.11.4.2 Declaring a Record Variable that Can Represent Partial Row
To declare a record variable that can represent a partial row of a database table or view, use this syntax:
variable_name cursor%ROWTYPE;
A cursor is associated with a query. For every column that the query selects, the record variable must have a corresponding, type-compatible field. If the query selects every column of the table or view, then the variable represents a full row; otherwise, the variable represents a partial row. The cursor must be either an explicit cursor or a strong cursor variable.
See Also:
-
"FETCH Statement" for complete syntax
-
"Cursors Overview" for information about cursors
-
"Explicit Cursors" for information about explicit cursors
-
"Cursor Variables" for information about cursor variables
-
Oracle Database SQL Language Reference for information about joins
Example 5-40 %ROWTYPE Variable Represents Partial Database Table Row
This example defines an explicit cursor whose query selects only the columns first_name
, last_name
, and phone_number
from the employees
table in the sample schema HR
. Then the example declares a record variable that has a field for each column that the cursor selects. The variable represents a partial row of employees
. Compare this example to Example 5-35.
Live SQL:
You can view and run this example on Oracle Live SQL at %ROWTYPE Variable Represents Partial Database Table Row
DECLARE
CURSOR c IS
SELECT first_name, last_name, phone_number
FROM employees;
friend c%ROWTYPE;
BEGIN
friend.first_name := 'John';
friend.last_name := 'Smith';
friend.phone_number := '1-650-555-1234';
DBMS_OUTPUT.PUT_LINE (
friend.first_name || ' ' ||
friend.last_name || ', ' ||
friend.phone_number
);
END;
/
Result:
John Smith, 1-650-555-1234
Example 5-41 %ROWTYPE Variable Represents Join Row
This example defines an explicit cursor whose query is a join and then declares a record variable that has a field for each column that the cursor selects.
Live SQL:
You can view and run this example on Oracle Live SQL at %ROWTYPE Variable Represents Join Row
DECLARE
CURSOR c2 IS
SELECT employee_id, email, employees.manager_id, location_id
FROM employees, departments
WHERE employees.department_id = departments.department_id;
join_rec c2%ROWTYPE; -- includes columns from two tables
BEGIN
NULL;
END;
/
5.11.4.3 %ROWTYPE Attribute and Virtual Columns
If you use the %ROWTYPE
attribute to define a record variable that represents a full row of a table that has a virtual column, then you cannot insert that record into the table. Instead, you must insert the individual record fields into the table, excluding the virtual column.
Example 5-42 Inserting %ROWTYPE Record into Table (Wrong)
This example creates a record variable that represents a full row of a table that has a virtual column, populates the record, and inserts the record into the table, causing ORA-54013.
DROP TABLE plch_departure; CREATE TABLE plch_departure ( destination VARCHAR2(100), departure_time DATE, delay NUMBER(10), expected GENERATED ALWAYS AS (departure_time + delay/24/60/60) ); DECLARE dep_rec plch_departure%ROWTYPE; BEGIN dep_rec.destination := 'X'; dep_rec.departure_time := SYSDATE; dep_rec.delay := 1500; INSERT INTO plch_departure VALUES dep_rec; END; /
Result:
DECLARE
*
ERROR at line 1:
ORA-54013: INSERT operation disallowed on virtual columns
ORA-06512: at line 8
Example 5-43 Inserting %ROWTYPE Record into Table (Right)
This solves the problem in Example 5-42 by inserting the individual record fields into the table, excluding the virtual column.
DECLARE dep_rec plch_departure%rowtype; BEGIN dep_rec.destination := 'X'; dep_rec.departure_time := SYSDATE; dep_rec.delay := 1500; INSERT INTO plch_departure (destination, departure_time, delay) VALUES (dep_rec.destination, dep_rec.departure_time, dep_rec.delay); end; /
Result:
PL/SQL procedure successfully completed.
5.11.4.4 %ROWTYPE Attribute and Invisible Columns
Suppose that you use the %ROWTYPE
attribute to define a record variable that represents a row of a table that has an invisible column, and then you make the invisible column visible.
If you define the record variable with a cursor, as in "Declaring a Record Variable that Can Represent Partial Row", then making the invisible column visible does not change the structure of the record variable.
However, if you define the record variable as in "Declaring a Record Variable that Always Represents Full Row" and use a SELECT
*
INTO
statement to assign values to the record, then making the invisible column visible does change the structure of the record—see Example 5-44.
See Also:
Oracle Database SQL Language Reference for general information about invisible columns
Example 5-44 %ROWTYPE Affected by Making Invisible Column Visible
CREATE TABLE t (a INT, b INT, c INT INVISIBLE); INSERT INTO t (a, b, c) VALUES (1, 2, 3); COMMIT; DECLARE t_rec t%ROWTYPE; -- t_rec has fields a and b, but not c BEGIN SELECT * INTO t_rec FROM t WHERE ROWNUM < 2; -- t_rec(a)=1, t_rec(b)=2 DBMS_OUTPUT.PUT_LINE('c = ' || t_rec.c); END; /
Result:
DBMS_OUTPUT.PUT_LINE('c = ' || t_rec.c);
*
ERROR at line 5:
ORA-06550: line 5, column 40:
PLS-00302: component 'C' must be declared
ORA-06550: line 5, column 3:
PL/SQL: Statement ignored
Make invisible column visible:
ALTER TABLE t MODIFY (c VISIBLE);
Result:
Table altered.
Repeat preceding anonymous block:
DECLARE t_rec t%ROWTYPE; -- t_rec has fields a, b, and c BEGIN SELECT * INTO t_rec FROM t WHERE ROWNUM < 2; -- t_rec(a)=1, t_rec(b)=2, -- t_rec(c)=3 DBMS_OUTPUT.PUT_LINE('c = ' || t_rec.c); END; /
Result:
c = 3
PL/SQL procedure successfully completed.
5.12 Assigning Values to Record Variables
A record variable means either a record variable or a record component of a composite variable.
To any record variable, you can assign a value to each field individually.
In some cases, you can assign the value of one record variable to another record variable.
If a record variable represents a full or partial row of a database table or view, you can assign the represented row to the record variable.
Topics
5.12.1 Assigning One Record Variable to Another
You can assign the value of one record variable to another record variable only in these cases:
-
The two variables have the same
RECORD
type. -
The target variable is declared with a
RECORD
type, the source variable is declared with%ROWTYPE
, their fields match in number and order, and corresponding fields have the same data type.
For record components of composite variables, the types of the composite variables need not match.
Example 5-45 Assigning Record to Another Record of Same RECORD Type
In this example, name1 and name2 have the same RECORD type, so you can assign the value of name1 to name2.
DECLARE TYPE name_rec IS RECORD ( first employees.first_name%TYPE DEFAULT 'John', last employees.last_name%TYPE DEFAULT 'Doe' ); name1 name_rec; name2 name_rec; BEGIN name1.first := 'Jane'; name1.last := 'Smith'; DBMS_OUTPUT.PUT_LINE('name1: ' || name1.first || ' ' || name1.last); name2 := name1; DBMS_OUTPUT.PUT_LINE('name2: ' || name2.first || ' ' || name2.last); END; /
Result:
name1: Jane Smith name2: Jane Smith
Example 5-46 Assigning %ROWTYPE Record to RECORD Type Record
In this example, the target variable is declared with a RECORD
type, the source variable is declared with %ROWTYPE
, their fields match in number and order, and corresponding fields have the same data type.
DECLARE TYPE name_rec IS RECORD ( first employees.first_name%TYPE DEFAULT 'John', last employees.last_name%TYPE DEFAULT 'Doe' ); CURSOR c IS SELECT first_name, last_name FROM employees; target name_rec; source c%ROWTYPE; BEGIN source.first_name := 'Jane'; source.last_name := 'Smith'; DBMS_OUTPUT.PUT_LINE ( 'source: ' || source.first_name || ' ' || source.last_name ); target := source; DBMS_OUTPUT.PUT_LINE ( 'target: ' || target.first || ' ' || target.last ); END; /
Result:
source: Jane Smith target: Jane Smith
Example 5-47 Assigning Nested Record to Another Record of Same RECORD Type
This example assigns the value of one nested record to another nested record. The nested records have the same RECORD
type, but the records in which they are nested do not.
DECLARE TYPE name_rec IS RECORD ( first employees.first_name%TYPE, last employees.last_name%TYPE ); TYPE phone_rec IS RECORD ( name name_rec, -- nested record phone employees.phone_number%TYPE ); TYPE email_rec IS RECORD ( name name_rec, -- nested record email employees.email%TYPE ); phone_contact phone_rec; email_contact email_rec; BEGIN phone_contact.name.first := 'John'; phone_contact.name.last := 'Smith'; phone_contact.phone := '1-650-555-1234'; email_contact.name := phone_contact.name; email_contact.email := ( email_contact.name.first || '.' || email_contact.name.last || '@' || 'example.com' ); DBMS_OUTPUT.PUT_LINE (email_contact.email); END; /
Result:
John.Smith@example.com
5.12.2 Assigning Full or Partial Rows to Record Variables
If a record variable represents a full or partial row of a database table or view, you can assign the represented row to the record variable.
Topics
5.12.2.1 Using SELECT INTO to Assign a Row to a Record Variable
The syntax of a simple SELECT
INTO
statement is:
SELECT select_list INTO record_variable_name FROM table_or_view_name;
For each column in select_list
, the record variable must have a corresponding, type-compatible field. The columns in select_list
must appear in the same order as the record fields.
See Also:
"SELECT INTO Statement" for complete syntax
Example 5-48 SELECT INTO Assigns Values to Record Variable
In this example, the record variable rec1
represents a partial row of the employees
table—the columns last_name
and employee_id
. The SELECT
INTO
statement selects from employees
the row for which job_id
is 'AD_PRES'
and assigns the values of the columns last_name
and employee_id
in that row to the corresponding fields of rec1
.
DECLARE TYPE RecordTyp IS RECORD ( last employees.last_name%TYPE, id employees.employee_id%TYPE ); rec1 RecordTyp; BEGIN SELECT last_name, employee_id INTO rec1 FROM employees WHERE job_id = 'AD_PRES'; DBMS_OUTPUT.PUT_LINE ('Employee #' || rec1.id || ' = ' || rec1.last); END; /
Result:
Employee #100 = King
5.12.2.2 Using FETCH to Assign a Row to a Record Variable
The syntax of a simple FETCH
statement is:
FETCH cursor INTO record_variable_name;
A cursor is associated with a query. For every column that the query selects, the record variable must have a corresponding, type-compatible field. The cursor must be either an explicit cursor or a strong cursor variable.
See Also:
-
"FETCH Statement" for complete syntax
-
"Cursors Overview" for information about all cursors
-
"Explicit Cursors" for information about explicit cursors
-
"Cursor Variables" for information about cursor variables
Example 5-49 FETCH Assigns Values to Record that Function Returns
In this example, each variable of RECORD
type EmpRecTyp
represents a partial row of the employees
table—the columns employee_id
and salary
. Both the cursor and the function return a value of type EmpRecTyp
. In the function, a FETCH
statement assigns the values of the columns employee_id
and salary
to the corresponding fields of a local variable of type EmpRecTyp
.
DECLARE
TYPE EmpRecTyp IS RECORD (
emp_id employees.employee_id%TYPE,
salary employees.salary%TYPE
);
CURSOR desc_salary RETURN EmpRecTyp IS
SELECT employee_id, salary
FROM employees
ORDER BY salary DESC;
highest_paid_emp EmpRecTyp;
next_highest_paid_emp EmpRecTyp;
FUNCTION nth_highest_salary (n INTEGER) RETURN EmpRecTyp IS
emp_rec EmpRecTyp;
BEGIN
OPEN desc_salary;
FOR i IN 1..n LOOP
FETCH desc_salary INTO emp_rec;
END LOOP;
CLOSE desc_salary;
RETURN emp_rec;
END nth_highest_salary;
BEGIN
highest_paid_emp := nth_highest_salary(1);
next_highest_paid_emp := nth_highest_salary(2);
DBMS_OUTPUT.PUT_LINE(
'Highest Paid: #' ||
highest_paid_emp.emp_id || ', $' ||
highest_paid_emp.salary
);
DBMS_OUTPUT.PUT_LINE(
'Next Highest Paid: #' ||
next_highest_paid_emp.emp_id || ', $' ||
next_highest_paid_emp.salary
);
END;
/
Result:
Highest Paid: #100, $24000 Next Highest Paid: #101, $17000
5.12.2.3 Using SQL Statements to Return Rows in PL/SQL Record Variables
The SQL statements INSERT
, UPDATE
, and DELETE
have an optional RETURNING
INTO
clause that can return the affected row in a PL/SQL record variable.
For information about this clause, see "RETURNING INTO Clause".
Example 5-50 UPDATE Statement Assigns Values to Record Variable
In this example, the UPDATE
statement updates the salary of an employee and returns the name and new salary of the employee in a record variable.
DECLARE TYPE EmpRec IS RECORD ( last_name employees.last_name%TYPE, salary employees.salary%TYPE ); emp_info EmpRec; old_salary employees.salary%TYPE; BEGIN SELECT salary INTO old_salary FROM employees WHERE employee_id = 100; UPDATE employees SET salary = salary * 1.1 WHERE employee_id = 100 RETURNING last_name, salary INTO emp_info; DBMS_OUTPUT.PUT_LINE ( 'Salary of ' || emp_info.last_name || ' raised from ' || old_salary || ' to ' || emp_info.salary ); END; /
Result:
Salary of King raised from 24000 to 26400
5.12.3 Assigning NULL to a Record Variable
Assigning the value NULL
to a record variable assigns the value NULL
to each of its fields.
This assignment is recursive; that is, if a field is a record, then its fields are also assigned the value NULL
.
Example 5-51 Assigning NULL to Record Variable
This example prints the fields of a record variable (one of which is a record) before and after assigning NULL
to it.
DECLARE
TYPE age_rec IS RECORD (
years INTEGER DEFAULT 35,
months INTEGER DEFAULT 6
);
TYPE name_rec IS RECORD (
first employees.first_name%TYPE DEFAULT 'John',
last employees.last_name%TYPE DEFAULT 'Doe',
age age_rec
);
name name_rec;
PROCEDURE print_name AS
BEGIN
DBMS_OUTPUT.PUT(NVL(name.first, 'NULL') || ' ');
DBMS_OUTPUT.PUT(NVL(name.last, 'NULL') || ', ');
DBMS_OUTPUT.PUT(NVL(TO_CHAR(name.age.years), 'NULL') || ' yrs ');
DBMS_OUTPUT.PUT_LINE(NVL(TO_CHAR(name.age.months), 'NULL') || ' mos');
END;
BEGIN
print_name;
name := NULL;
print_name;
END;
/
Result:
John Doe, 35 yrs 6 mos NULL NULL, NULL yrs NULL mos
5.13 Record Comparisons
Records cannot be tested natively for nullity, equality, or inequality.
These BOOLEAN
expressions are illegal:
-
My_Record IS NULL
-
My_Record_1 = My_Record_2
-
My_Record_1 > My_Record_2
You must write your own functions to implement such tests. For information about writing functions, see PL/SQL Subprograms.
5.14 Inserting Records into Tables
The PL/SQL extension to the SQL INSERT
statement lets you insert a record into a table.
The record must represent a row of the table. For more information, see "INSERT Statement Extension". For restrictions on inserting records into tables, see "Restrictions on Record Inserts and Updates".
To efficiently insert a collection of records into a table, put the INSERT
statement inside a FORALL
statement. For information about the FORALL
statement, see "FORALL Statement".
Example 5-52 Initializing Table by Inserting Record of Default Values
This example creates the table schedule
and initializes it by putting default values in a record and inserting the record into the table for each week. (The COLUMN
formatting commands are from SQL*Plus.)
DROP TABLE schedule;
CREATE TABLE schedule (
week NUMBER,
Mon VARCHAR2(10),
Tue VARCHAR2(10),
Wed VARCHAR2(10),
Thu VARCHAR2(10),
Fri VARCHAR2(10),
Sat VARCHAR2(10),
Sun VARCHAR2(10)
);
DECLARE
default_week schedule%ROWTYPE;
i NUMBER;
BEGIN
default_week.Mon := '0800-1700';
default_week.Tue := '0800-1700';
default_week.Wed := '0800-1700';
default_week.Thu := '0800-1700';
default_week.Fri := '0800-1700';
default_week.Sat := 'Day Off';
default_week.Sun := 'Day Off';
FOR i IN 1..6 LOOP
default_week.week := i;
INSERT INTO schedule VALUES default_week;
END LOOP;
END;
/
COLUMN week FORMAT 99
COLUMN Mon FORMAT A9
COLUMN Tue FORMAT A9
COLUMN Wed FORMAT A9
COLUMN Thu FORMAT A9
COLUMN Fri FORMAT A9
COLUMN Sat FORMAT A9
COLUMN Sun FORMAT A9
SELECT * FROM schedule;
Result:
WEEK MON TUE WED THU FRI SAT SUN ---- --------- --------- --------- --------- --------- --------- --------- 1 0800-1700 0800-1700 0800-1700 0800-1700 0800-1700 Day Off Day Off 2 0800-1700 0800-1700 0800-1700 0800-1700 0800-1700 Day Off Day Off 3 0800-1700 0800-1700 0800-1700 0800-1700 0800-1700 Day Off Day Off 4 0800-1700 0800-1700 0800-1700 0800-1700 0800-1700 Day Off Day Off 5 0800-1700 0800-1700 0800-1700 0800-1700 0800-1700 Day Off Day Off 6 0800-1700 0800-1700 0800-1700 0800-1700 0800-1700 Day Off Day Off
5.15 Updating Rows with Records
The PL/SQL extension to the SQL UPDATE
statement lets you update one or more table rows with a record.
The record must represent a row of the table. For more information, see "UPDATE Statement Extensions".
For restrictions on updating table rows with a record, see "Restrictions on Record Inserts and Updates".
To efficiently update a set of rows with a collection of records, put the UPDATE
statement inside a FORALL
statement. For information about the FORALL
statement, see "FORALL Statement".
Example 5-53 Updating Rows with Record
This example updates the first three weeks of the table schedule
(defined in Example 5-52) by putting the new values in a record and updating the first three rows of the table with that record.
DECLARE default_week schedule%ROWTYPE; BEGIN default_week.Mon := 'Day Off'; default_week.Tue := '0900-1800'; default_week.Wed := '0900-1800'; default_week.Thu := '0900-1800'; default_week.Fri := '0900-1800'; default_week.Sat := '0900-1800'; default_week.Sun := 'Day Off'; FOR i IN 1..3 LOOP default_week.week := i; UPDATE schedule SET ROW = default_week WHERE week = i; END LOOP; END; / SELECT * FROM schedule;
Result:
WEEK MON TUE WED THU FRI SAT SUN ---- --------- --------- --------- --------- --------- --------- --------- 1 Day Off 0900-1800 0900-1800 0900-1800 0900-1800 0900-1800 Day Off 2 Day Off 0900-1800 0900-1800 0900-1800 0900-1800 0900-1800 Day Off 3 Day Off 0900-1800 0900-1800 0900-1800 0900-1800 0900-1800 Day Off 4 0800-1700 0800-1700 0800-1700 0800-1700 0800-1700 Day Off Day Off 5 0800-1700 0800-1700 0800-1700 0800-1700 0800-1700 Day Off Day Off 6 0800-1700 0800-1700 0800-1700 0800-1700 0800-1700 Day Off Day Off
5.16 Restrictions on Record Inserts and Updates
These restrictions apply to record inserts and updates:
-
Record variables are allowed only in these places:
-
On the right side of the
SET
clause in anUPDATE
statement -
In the
VALUES
clause of anINSERT
statement -
In the
INTO
subclause of aRETURNING
clause
Record variables are not allowed in a
SELECT
list,WHERE
clause,GROUP
BY
clause, orORDER
BY
clause. -
-
The keyword
ROW
is allowed only on the left side of aSET
clause. Also, you cannot useROW
with a subquery. -
In an
UPDATE
statement, only oneSET
clause is allowed ifROW
is used. -
If the
VALUES
clause of anINSERT
statement contains a record variable, no other variable or value is allowed in the clause. -
If the
INTO
subclause of aRETURNING
clause contains a record variable, no other variable or value is allowed in the subclause. -
These are not supported:
-
Nested
RECORD
types -
Functions that return a
RECORD
type -
Record inserts and updates using the
EXECUTE
IMMEDIATE
statement.
-