11 Loading Objects, LOBs, and Collections with SQL*Loader

You can use SQL*Loader to load column objects in various formats and to load object tables, REF columns, LOBs, and collections.

Parent topic: SQL*Loader

11.1 Loading Column Objects

Column objects in the control file are described in terms of their attributes.

If the object type on which the column object is based is declared to be nonfinal, then the column object in the control file may be described in terms of the attributes, both derived and declared, of any subtype derived from the base object type. In the data file, the data corresponding to each of the attributes of a column object is in a data field similar to that corresponding to a simple relational column.

Note:

With SQL*Loader support for complex data types such as column objects, the possibility arises that two identical field names could exist in the control file, one corresponding to a column, the other corresponding to a column object's attribute. Certain clauses can refer to fields (for example, WHEN, NULLIF, DEFAULTIF, SID, OID, REF, BFILE, and so on), causing a naming conflict if identically named fields exist in the control file.

Therefore, if you use clauses that refer to fields, then you must specify the full name. For example, if field fld1 is specified to be a COLUMN OBJECT and it contains field fld2, then when you specify fld2 in a clause such as NULLIF, you must use the full field name fld1.fld2.

The following sections show examples of loading column objects:

Parent topic: Loading Objects, LOBs, and Collections with SQL*Loader

11.1.1 Loading Column Objects in Stream Record Format

With stream record formats, you can use SQL*Loader to load records with multi-line fields by specifying a delimitor on column objects.

In stream record format, SQL*Loader forms records by scanning for the record terminator. To show how to use stream record formats, consider the following example, in which the data is in predetermined size fields. The newline character marks the end of a physical record. You can also mark the end of a physical record by using a custom record separator in the operating system file-processing clause (os_file_proc_clause).

Example 11-1 Loading Column Objects in Stream Record Format

Control File Contents

LOAD DATA
INFILE 'example.dat'
INTO TABLE departments
   (dept_no     POSITION(01:03)    CHAR,
    dept_name   POSITION(05:15)    CHAR,
1   dept_mgr    COLUMN OBJECT
      (name     POSITION(17:33)    CHAR,
       age      POSITION(35:37)    INTEGER EXTERNAL,
       emp_id   POSITION(40:46)    INTEGER EXTERNAL) )

Data File (example.dat) 

101 Mathematics  Johnny Quest       30   1024
237 Physics      Albert Einstein   65   0000

In the example, note the callout 1 at dept_mgr COLUMN OBJECT. You can apply this type of column object specification recursively to describe nested column objects.

Parent topic: Loading Column Objects

11.1.2 Loading Column Objects in Variable Record Format

You can load column objects in variable record format.

Example 11-2 shows a case in which the data is in delimited fields.

Example 11-2 Loading Column Objects in Variable Record Format

Control File Contents

LOAD DATA
1 INFILE 'sample.dat' "var 6"
INTO TABLE departments
FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
2  (dept_no
   dept_name, 
   dept_mgr       COLUMN OBJECT
      (name       CHAR(30), 
      age         INTEGER EXTERNAL(5), 
      emp_id      INTEGER EXTERNAL(5)) )

Data File (sample.dat)

3  000034101,Mathematics,Johny Q.,30,1024,
   000039237,Physics,"Albert Einstein",65,0000,

Note:

The callouts, in bold, to the left of the example correspond to the following notes:

  1. The "var" string includes the number of bytes in the length field at the beginning of each record (in this example, the number is 6). If no value is specified, then the default is 5 bytes. The maximum size of a variable record is 2^32-1. Specifying larger values will result in an error.

  2. Although no positional specifications are given, the general syntax remains the same (the column object's name followed by the list of its attributes enclosed in parentheses). Also note that an omitted type specification defaults to CHAR of length 255.

  3. The first 6 bytes (italicized) specify the length of the forthcoming record. These length specifications include the newline characters, which are ignored thanks to the terminators after the emp_id field.

Parent topic: Loading Column Objects

11.1.3 Loading Nested Column Objects

You can load nested column objects.

Example 11-3 shows a control file describing nested column objects (one column object nested in another column object).

Example 11-3 Loading Nested Column Objects

Control File Contents

LOAD DATA
INFILE `sample.dat'
INTO TABLE departments_v2
FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
   (dept_no      CHAR(5), 
   dept_name     CHAR(30), 
   dept_mgr      COLUMN OBJECT
      (name      CHAR(30), 
      age        INTEGER EXTERNAL(3),
      emp_id     INTEGER EXTERNAL(7),
1     em_contact COLUMN OBJECT
         (name      CHAR(30), 
         phone_num  CHAR(20))))

Data File (sample.dat)

101,Mathematics,Johny Q.,30,1024,"Barbie",650-251-0010,
237,Physics,"Albert Einstein",65,0000,Wife Einstein,654-3210,

Note:

The callout, in bold, to the left of the example corresponds to the following note:

  1. This entry specifies a column object nested within a column object.

Parent topic: Loading Column Objects

11.1.4 Loading Column Objects with a Derived Subtype

You can load column objects with a derived subtype.

Example 11-4 shows a case in which a nonfinal base object type has been extended to create a new derived subtype. Although the column object in the table definition is declared to be of the base object type, SQL*Loader allows any subtype to be loaded into the column object, provided that the subtype is derived from the base object type.

Example 11-4 Loading Column Objects with a Subtype

Object Type Definitions

CREATE TYPE person_type AS OBJECT
  (name     VARCHAR(30),
   ssn      NUMBER(9)) not final;

CREATE TYPE employee_type UNDER person_type
  (empid    NUMBER(5));

CREATE TABLE personnel
  (deptno   NUMBER(3),
   deptname VARCHAR(30),
   person   person_type);

Control File Contents

LOAD DATA
INFILE 'sample.dat'
INTO TABLE personnel
FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
   (deptno        INTEGER EXTERNAL(3),
    deptname      CHAR,
1   person        COLUMN OBJECT TREAT AS employee_type
      (name       CHAR,
       ssn        INTEGER EXTERNAL(9),
2      empid      INTEGER EXTERNAL(5)))

Data File (sample.dat)

101,Mathematics,Johny Q.,301189453,10249,
237,Physics,"Albert Einstein",128606590,10030,

Note:

The callouts, in bold, to the left of the example correspond to the following notes:

  1. The TREAT AS clause indicates that SQL*Loader should treat the column object person as if it were declared to be of the derived type employee_type, instead of its actual declared type, person_type.

  2. The empid attribute is allowed here because it is an attribute of the employee_type. If the TREAT AS clause had not been specified, then this attribute would have resulted in an error, because it is not an attribute of the column's declared type.

Parent topic: Loading Column Objects

11.1.5 Specifying Null Values for Objects

You can specify null values for objects.

Specifying null values for nonscalar data types is somewhat more complex than for scalar data types. An object can have a subset of its attributes be null, it can have all of its attributes be null (an attributively null object), or it can be null itself (an atomically null object).

Parent topic: Loading Column Objects

11.1.5.1 Specifying Attribute Nulls

You can specify attribute nulls.

In fields corresponding to column objects, you can use the NULLIF clause to specify the field conditions under which a particular attribute should be initialized to NULL. Example 11-5 demonstrates this.

Example 11-5 Specifying Attribute Nulls Using the NULLIF Clause

Control File Contents

LOAD DATA
INFILE 'sample.dat'
INTO TABLE departments
  (dept_no      POSITION(01:03)    CHAR,
  dept_name     POSITION(05:15)    CHAR NULLIF dept_name=BLANKS,
  dept_mgr      COLUMN OBJECT
1    ( name     POSITION(17:33)    CHAR NULLIF dept_mgr.name=BLANKS,
1    age        POSITION(35:37)    INTEGER EXTERNAL NULLIF dept_mgr.age=BLANKS,
1    emp_id     POSITION(40:46)    INTEGER EXTERNAL NULLIF dept_mgr.empid=BLANKS))

Data File (sample.dat)

2  101             Johny Quest            1024
   237   Physics   Albert Einstein   65   0000

Note:

The callouts, in bold, to the left of the example correspond to the following notes:

  1. The NULLIF clause corresponding to each attribute states the condition under which the attribute value should be NULL

  2. The age attribute of the dept_mgr value is null. The dept_name value is also null.

11.1.5.2 Specifying Atomic Nulls

You can specify atomic nulls.

To specify in the control file the condition under which a particular object should take a null value (atomic null), you must follow that object's name with a NULLIF clause based on a logical combination of any of the mapped fields (for example, in Example 11-5, the named mapped fields would be dept_no, dept_name, name, age, emp_id, but dept_mgr would not be a named mapped field because it does not correspond (is not mapped) to any field in the data file).

Although the preceding is workable, it is not ideal when the condition under which an object should take the value of null is independent of any of the mapped fields. In such situations, you can use filler fields.

You can map a filler field to the field in the data file (indicating if a particular object is atomically null or not) and use the filler field in the field condition of the NULLIF clause of the particular object. This is shown in Example 11-6.

Example 11-6 Loading Data Using Filler Fields

Control File Contents

LOAD DATA
INFILE 'sample.dat'
INTO TABLE departments_v2
FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
   (dept_no         CHAR(5),
   dept_name        CHAR(30),
1  is_null          FILLER CHAR,
2  dept_mgr         COLUMN OBJECT NULLIF is_null=BLANKS
      (name         CHAR(30) NULLIF dept_mgr.name=BLANKS, 
      age           INTEGER EXTERNAL(3) NULLIF dept_mgr.age=BLANKS,
      emp_id        INTEGER EXTERNAL(7) 
                    NULLIF dept_mgr.emp_id=BLANKS,
      em_contact    COLUMN OBJECT NULLIF is_null2=BLANKS
         (name      CHAR(30) 
                    NULLIF dept_mgr.em_contact.name=BLANKS, 
         phone_num  CHAR(20) 
                    NULLIF dept_mgr.em_contact.phone_num=BLANKS)),
1  is_null2         FILLER CHAR)

Data File (sample.dat)

101,Mathematics,n,Johny Q.,,1024,"Barbie",608-251-0010,,
237,Physics,,"Albert Einstein",65,0000,,650-654-3210,n,

Note:

The callouts, in bold, to the left of the example correspond to the following notes:

  1. The filler field (data file mapped; no corresponding column) is of type CHAR (because it is a delimited field, the CHAR defaults to CHAR(255)). Note that the NULLIF clause is not applicable to the filler field itself

  2. Gets the value of null (atomic null) if the is_null field is blank.

11.1.6 Loading Column Objects with User-Defined Constructors

You can load column objects with user-defined constructors.

The Oracle database automatically supplies a default constructor for every object type. This constructor requires that all attributes of the type be specified as arguments in a call to the constructor. When a new instance of the object is created, its attributes take on the corresponding values in the argument list. This constructor is known as the attribute-value constructor. SQL*Loader uses the attribute-value constructor by default when loading column objects.

It is possible to override the attribute-value constructor by creating one or more user-defined constructors. When you create a user-defined constructor, you must supply a type body that performs the user-defined logic whenever a new instance of the object is created. A user-defined constructor may have the same argument list as the attribute-value constructor but differ in the logic that its type body implements.

When the argument list of a user-defined constructor function matches the argument list of the attribute-value constructor, there is a difference in behavior between conventional and direct path SQL*Loader. Conventional path mode results in a call to the user-defined constructor. Direct path mode results in a call to the attribute-value constructor. Example 11-7 illustrates this difference.

Example 11-7 Loading a Column Object with Constructors That Match

Object Type Definitions

CREATE TYPE person_type AS OBJECT
     (name     VARCHAR(30),
      ssn      NUMBER(9)) not final;

   CREATE TYPE employee_type UNDER person_type
     (empid    NUMBER(5),
   -- User-defined constructor that looks like an attribute-value constructor
      CONSTRUCTOR FUNCTION
        employee_type (name VARCHAR2, ssn NUMBER, empid NUMBER)
        RETURN SELF AS RESULT);

   CREATE TYPE BODY employee_type AS
     CONSTRUCTOR FUNCTION
        employee_type (name VARCHAR2, ssn NUMBER, empid NUMBER)
      RETURN SELF AS RESULT AS
   --User-defined constructor makes sure that the name attribute is uppercase.
      BEGIN
        SELF.name  := UPPER(name);
        SELF.ssn   := ssn;
        SELF.empid := empid;
        RETURN;
      END;

   CREATE TABLE personnel
     (deptno   NUMBER(3),
      deptname VARCHAR(30),
      employee employee_type);

Control File Contents

LOAD DATA
   INFILE *
   REPLACE
   INTO TABLE personnel
   FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
      (deptno        INTEGER EXTERNAL(3),
       deptname      CHAR,
       employee      COLUMN OBJECT
         (name       CHAR,
          ssn        INTEGER EXTERNAL(9),
          empid      INTEGER EXTERNAL(5)))

   BEGINDATA
1  101,Mathematics,Johny Q.,301189453,10249,
   237,Physics,"Albert Einstein",128606590,10030,

Note:

The callout, in bold, to the left of the example corresponds to the following note:

  1. When this control file is run in conventional path mode, the name fields, Johny Q. and Albert Einstein, are both loaded in uppercase. This is because the user-defined constructor is called in this mode. In contrast, when this control file is run in direct path mode, the name fields are loaded exactly as they appear in the input data. This is because the attribute-value constructor is called in this mode.

It is possible to create a user-defined constructor whose argument list does not match that of the attribute-value constructor. In this case, both conventional and direct path modes will result in a call to the attribute-value constructor. Consider the definitions in Example 11-8.

Example 11-8 Loading a Column Object with Constructors That Do Not Match

Object Type Definitions

CREATE SEQUENCE employee_ids
    START     WITH  1000
    INCREMENT BY    1;

   CREATE TYPE person_type AS OBJECT
     (name     VARCHAR(30),
      ssn      NUMBER(9)) not final;

   CREATE TYPE employee_type UNDER person_type
     (empid    NUMBER(5),
   -- User-defined constructor that does not look like an attribute-value 
   -- constructor
      CONSTRUCTOR FUNCTION
        employee_type (name VARCHAR2, ssn NUMBER)
        RETURN SELF AS RESULT);

   CREATE TYPE BODY employee_type AS
     CONSTRUCTOR FUNCTION
        employee_type (name VARCHAR2, ssn NUMBER)
      RETURN SELF AS RESULT AS
   -- This user-defined constructor makes sure that the name attribute is in
   -- lowercase and assigns the employee identifier based on a sequence.
        nextid     NUMBER;
        stmt       VARCHAR2(64);
      BEGIN

        stmt := 'SELECT employee_ids.nextval FROM DUAL';
        EXECUTE IMMEDIATE stmt INTO nextid;

        SELF.name  := LOWER(name);
        SELF.ssn   := ssn;
        SELF.empid := nextid; 
        RETURN;
      END;

   CREATE TABLE personnel
     (deptno   NUMBER(3),
      deptname VARCHAR(30),
      employee employee_type);

If the control file described in Example 11-7 is used with these definitions, then the name fields are loaded exactly as they appear in the input data (that is, in mixed case). This is because the attribute-value constructor is called in both conventional and direct path modes.

It is still possible to load this table using conventional path mode by explicitly making reference to the user-defined constructor in a SQL expression. Example 11-9 shows how this can be done.

Example 11-9 Using SQL to Load Column Objects When Constructors Do Not Match

Control File Contents

LOAD DATA
   INFILE *
   REPLACE
   INTO TABLE personnel
   FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
      (deptno        INTEGER EXTERNAL(3),
       deptname      CHAR,
       name          BOUNDFILLER CHAR,
       ssn           BOUNDFILLER INTEGER EXTERNAL(9),
1      employee      EXPRESSION "employee_type(:NAME, :SSN)")

   BEGINDATA
1  101,Mathematics,Johny Q.,301189453,
   237,Physics,"Albert Einstein",128606590,

Note:

The callouts, in bold, to the left of the example correspond to the following note:

  1. When this control file is run in conventional path mode, the name fields, Johny Q. and Albert Einstein, are both loaded in uppercase. This is because the user-defined constructor is called in this mode. In contrast, when this control file is run in direct path mode, the name fields are loaded exactly as they appear in the input data. This is because the attribute-value constructor is called in this mode.

If the control file in Example 11-9 is used in direct path mode, then the following error is reported: 

SQL*Loader-951: Error calling once/load initialization
ORA-26052: Unsupported type 121 for SQL expression on column EMPLOYEE.

Parent topic: Loading Column Objects

11.2 Loading Object Tables

The control file syntax required to load an object table is nearly identical to that used to load a typical relational table.

Example 11-10 demonstrates loading an object table with primary-key-based object identifiers (OIDs).

Example 11-10 Loading an Object Table with Primary Key OIDs

Control File Contents

LOAD DATA
INFILE 'sample.dat'
DISCARDFILE 'sample.dsc'
BADFILE 'sample.bad'
REPLACE
INTO TABLE employees 
FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
   (name    CHAR(30)                NULLIF name=BLANKS,
   age      INTEGER EXTERNAL(3)     NULLIF age=BLANKS,
   emp_id   INTEGER EXTERNAL(5))

Data File (sample.dat)

Johny Quest, 18, 007,
Speed Racer, 16, 000,

By looking only at the preceding control file you might not be able to determine if the table being loaded was an object table with system-generated OIDs, an object table with primary-key-based OIDs, or a relational table.

You may want to load data that already contains system-generated OIDs and to specify that instead of generating new OIDs, the existing OIDs in the data file should be used. To do this, you would follow the INTO TABLE clause with the OID clause: 

OID (fieldname)

In this clause, fieldname is the name of one of the fields (typically a filler field) from the field specification list that is mapped to a data field that contains the system-generated OIDs. SQL*Loader assumes that the OIDs provided are in the correct format and that they preserve OID global uniqueness. Therefore, to ensure uniqueness, you should use the Oracle OID generator to generate the OIDs to be loaded.

The OID clause can only be used for system-generated OIDs, not primary-key-based OIDs.

Example 11-11 demonstrates loading system-generated OIDs with the row objects.

Example 11-11 Loading OIDs

Control File Contents

   LOAD DATA
   INFILE 'sample.dat'
   INTO TABLE employees_v2 
1  OID (s_oid)
   FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
      (name    CHAR(30)                NULLIF name=BLANKS,
      age      INTEGER EXTERNAL(3)    NULLIF age=BLANKS,
      emp_id   INTEGER EXTERNAL(5),
2     s_oid    FILLER CHAR(32))

Data File (sample.dat)

3  Johny Quest, 18, 007, 21E978406D3E41FCE03400400B403BC3,
   Speed Racer, 16, 000, 21E978406D4441FCE03400400B403BC3,

Note:

The callouts, in bold, to the left of the example correspond to the following notes:

  1. The OID clause specifies that the s_oid loader field contains the OID. The parentheses are required

  2. If s_oid does not contain a valid hexadecimal number, then the particular record is rejected.

  3. The OID in the data file is a character string and is interpreted as a 32-digit hexadecimal number. The 32-digit hexadecimal number is later converted into a 16-byte RAW and stored in the object table.

  • Loading Object Tables with Subtypes
    If an object table's row object is based on a nonfinal type, then SQL*Loader allows for any derived subtype to be loaded into the object table.

Parent topic: Loading Objects, LOBs, and Collections with SQL*Loader

11.2.1 Loading Object Tables with Subtypes

If an object table's row object is based on a nonfinal type, then SQL*Loader allows for any derived subtype to be loaded into the object table.

The syntax required to load an object table with a derived subtype is almost identical to that used for a typical relational table. However, in this case, the actual subtype to be used must be named, so that SQL*Loader can determine if it is a valid subtype for the object table. Use these examples to understand the differences.

Example 11-12 Loading an Object Table with a Subtype

Review the object type definitions, and review the callouts (in bold) to understand how the control file is configured.

Object Type Definitions

CREATE TYPE employees_type AS OBJECT
  (name     VARCHAR2(30),
   age      NUMBER(3),
   emp_id   NUMBER(5)) not final;

CREATE TYPE hourly_emps_type UNDER employees_type
  (hours    NUMBER(3));

CREATE TABLE employees_v3 of employees_type;

Control File Contents

   LOAD DATA

   INFILE 'sample.dat'
   INTO TABLE employees_v3
1  TREAT AS hourly_emps_type
   FIELDS TERMINATED BY ','
     (name     CHAR(30),
      age      INTEGER EXTERNAL(3),
      emp_id   INTEGER EXTERNAL(5),
2     hours    INTEGER EXTERNAL(2))

Data File (sample.dat) 

   Johny Quest, 18, 007, 32,
   Speed Racer, 16, 000, 20,

Note:

The callouts in bold, to the left of the example, correspond to the following notes:

  1. The TREAT AS clause directs SQL*Loader to treat the object table as if it was declared to be of type hourly_emps_type, instead of its actual declared type, employee_type.

  2. The hours attribute is allowed here, because it is an attribute of the hourly_emps_type. If the TREAT AS clause is not specified, then using this attribute results in an error, because it is not an attribute of the object table's declared type.

Parent topic: Loading Object Tables

11.3 Loading REF Columns with SQL*Loader

SQL*Loader can load system-generated OID REF columns, primary-key-based REF columns, and unscoped REF columns that allow primary keys.

A REF is an Oracle built-in data type that is a logical "pointer" to an object in an object table. For each of these types of REF columns, you must specify table names correctly for the type.

Parent topic: Loading Objects, LOBs, and Collections with SQL*Loader

11.3.1 Specifying Table Names in a REF Clause

Use these examples to see how to describe REF clauses in the SQL*Loader control file, and understand case sensitivity.

Note:

The information in this section applies only to environments in which the release of both SQL*Loader and Oracle Database are 11g release 1 (11.1) or later. It does not apply to environments in which either SQL*Loader, Oracle Database, or both, are at an earlier release.

Example 11-13 REF Clause descriptions in the SQL*Loader Control file

In the SQL*Loader control file, the description of the field corresponding to a REF column consists of the column name, followed by a REF clause. The REF clause takes as arguments the table name and any attributes applicable to the type of REF column being loaded. The table names can either be specified dynamically (using filler fields), or as constants. The table name can also be specified with or without the schema name.

Whether you specify the table name in the REF clause as a constant, or you specify it by using a filler field, SQL*Loader interprets this specification as interpreted as case-sensitive. If you do not keep this in mind, then the following issues can occur:

  • If user SCOTT creates a table named table2 in lowercase without quotation marks around the table name, then it can be used in a REF clause in any of the following ways:

    • REF(constant 'TABLE2', ...)

    • REF(constant '"TABLE2"', ...)

    • REF(constant 'SCOTT.TABLE2', ...)

  • If user SCOTT creates a table named "Table2" using quotation marks around a mixed-case name, then it can be used in a REF clause in any of the following ways:

    • REF(constant 'Table2', ...)

    • REF(constant '"Table2"', ...)

    • REF(constant 'SCOTT.Table2', ...)

In both of those situations, if constant is replaced with a filler field, then the same values as shown in the examples will also work if they are placed in the data section.

Parent topic: Loading REF Columns with SQL*Loader

11.3.2 System-Generated OID REF Columns

When you load system-generated REF columns, SQL*Loader assumes that the actual OIDs from which the REF columns are constructed are in the data file, with the data.

The description of the field corresponding to a REF column consists of the column name followed by the REF clause.

The REF clause takes as arguments the table name and an OID. Note that the arguments can be specified either as constants or dynamically (using filler fields). Refer to the ref_spec SQL*Loader syntax for details.

Example 11-14 Loading System-Generated REF Columns

The following example shows how to load system-generated OID REF columns; note the callouts in bold:

Control File Contents

LOAD DATA
INFILE 'sample.dat'
INTO TABLE departments_alt_v2
FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
  (dept_no      CHAR(5),
   dept_name    CHAR(30),
1 dept_mgr     REF(t_name, s_oid),
   s_oid        FILLER CHAR(32),
   t_name       FILLER CHAR(30))

Data File (sample.dat) 

22345, QuestWorld, 21E978406D3E41FCE03400400B403BC3, EMPLOYEES_V2,
23423, Geography, 21E978406D4441FCE03400400B403BC3, EMPLOYEES_V2,

Note:

The callout in bold, to the left of the example, corresponds to the following note:

  1. If the specified table does not exist, then the record is rejected. The dept_mgr field itself does not map to any field in the data file.

Related Topics

Parent topic: Loading REF Columns with SQL*Loader

11.3.3 Primary Key REF Columns

To load a primary key REF column, the SQL*Loader control-file field description must provide the column name followed by a REF clause.

The REF clause takes for arguments a comma-delimited list of field names and constant values. The first argument is the table name, followed by arguments that specify the primary key OID on which the REF column to be loaded is based. Refer to the SQL*Loader syntax for ref_spec for details.

SQL*Loader assumes that the ordering of the arguments matches the relative ordering of the columns making up the primary key OID in the referenced table.

Example 11-15 Loading Primary Key REF Columns

The following example demonstrates loading primary key REF columns:

Control File Contents

LOAD DATA
INFILE 'sample.dat'
INTO TABLE departments_alt
FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
 (dept_no       CHAR(5),
 dept_name      CHAR(30),
 dept_mgr       REF(CONSTANT 'EMPLOYEES', emp_id),
 emp_id         FILLER CHAR(32))

Data File (sample.dat)

22345, QuestWorld, 007,
23423, Geography, 000,

Related Topics

Parent topic: Loading REF Columns with SQL*Loader

11.3.4 Unscoped REF Columns That Allow Primary Keys

An unscoped REF column that allows primary keys can reference both system-generated and primary key REFs.

The syntax for loading data into an unscoped REF column is the same syntax you use when loading data into a system-generated OID REF column, or into a primary-key-based REF column.

The following restrictions apply when loading into an unscoped REF column that allows primary keys:

  • Only one type of REF can be referenced by this column during a single-table load, either system-generated or primary key, but not both. If you try to reference both types, then the data row will be rejected with an error message indicating that the referenced table name is invalid.

  • If you are loading unscoped primary key REFs to this column, then only one object table can be referenced during a single-table load. That is, to load unscoped primary key REFs, some pointing to object table X and some pointing to object table Y, you must do one of the following:

    • Perform two single-table loads.
    • Perform a single load using multiple INTO TABLE clauses for which the WHEN clause keys off some aspect of the data, such as the object table name for the unscoped primary key REF.

    If you do not use either of these methods, then the data row is rejected with an error message indicating that the referenced table name is invalid.

  • SQL*Loader does not support unscoped primary key REFs in collections.

  • If you are loading system-generated REFs into this REF column, then any limitations that apply to system-generated OID REF columns also apply.

  • If you are loading primary key REFs into this REF column, then any limitations that apply to primary key REF columns also apply.

    Note:

    For an unscoped REF column that allows primary keys, SQL*Loader takes the first valid object table parsed (either from the REF directive or from the data rows). SQL*Loader then uses that object table's OID type to determine the REF type that can be referenced in that single-table load.

Example 11-16 Single Load Using Multiple INTO TABLE Clause Method

In this example, the WHEN clauses key off the "CUSTOMERS_PK" data specified by object table names for the unscoped primary key REF tables cust_tbl and cust_no: 

LOAD DATA 
INFILE 'data.dat' 

INTO TABLE orders_apk 
APPEND 
when CUST_TBL = "CUSTOMERS_PK" 
fields terminated by "," 
( 
  order_no   position(1)  char, 
  cust_tbl FILLER     char, 
  cust_no  FILLER     char, 
  cust   REF (cust_tbl, cust_no) NULLIF order_no='0' 
) 

INTO TABLE orders_apk 
APPEND 
when CUST_TBL = "CUSTOMERS_PK2" 
fields terminated by "," 
( 
  order_no  position(1)  char, 
  cust_tbl FILLER     char, 
  cust_no  FILLER     char, 
  cust   REF (cust_tbl, cust_no) NULLIF order_no='0' 
)

Parent topic: Loading REF Columns with SQL*Loader

11.4 Loading LOBs with SQL*Loader

Find out which large object types (LOBs) SQL*Loader can load, and see examples of how to load LOB Data.

Parent topic: Loading Objects, LOBs, and Collections with SQL*Loader

11.4.1 Loading LOB Data from a Primary Data File

You can load internal LOBs (BLOBs, CLOBs, NCLOBs) or XML columns from a primary data file.

To load internal LOBs or XML columns from a primary data file, you can use the following standard SQL*Loader formats:

  • Predetermined size fields

  • Delimited fields

  • Length-value pair fields

Parent topic: Loading LOBs with SQL*Loader

11.4.1.1 LOB Data in Predetermined Size Fields

See how loading LOBs into predetermined size fields is a very fast and conceptually simple format in which to load LOBs.

Note:

Because the LOBs you are loading can be of different sizes, you can use whitespace to pad the LOB data to make the LOBs all of equal length within a particular data field.

To load LOBs using predetermined size fields, you should use either CHAR or RAW as the loading data type.

Example 11-17 Loading LOB Data in Predetermined Size Fields

Review the example control file and data file, and note the callouts in bold:

Control File Contents

LOAD DATA 
INFILE 'sample.dat' "fix 501"
INTO TABLE person_table
   (name       POSITION(01:21)       CHAR,
1  "RESUME"    POSITION(23:500)      CHAR   DEFAULTIF "RESUME"=BLANKS)

Data File (sample.dat) 

Julia Nayer      Julia Nayer
             500 Example Parkway
             jnayer@us.example.com ...

Note:

The callout in bold, to the left of the example, corresponds to the following note:

  1. Because the DEFAULTIF clause is used, if the data field containing the resume is empty, then the result is an empty LOB rather than a null LOB. However, if a NULLIF clause had been used instead of DEFAULTIF, then the empty data field would be null.

    You can use SQL*Loader data types other than CHAR to load LOBs. For example, when loading BLOBs, you would probably want to use the RAW data type.

11.4.1.2 LOB Data in Delimited Fields

Consider using delimited fields when you want to load LOBs of different sizes within the same column (data file field) with SQL*Loader.

The delimited field format handles LOBs of different sizes within the same column (data file field) without a problem. However, this added flexibility can affect performance, because SQL*Loader must scan through the data, looking for the delimiter string.

As with single-character delimiters, when you specify string delimiters, you should consider the character set of the data file. When the character set of the data file is different than that of the control file, you can specify the delimiters in hexadecimal notation (that is, X'hexadecimal string'). If the delimiters are specified in hexadecimal notation, then the specification must consist of characters that are valid in the character set of the input data file. In contrast, if hexadecimal notation is not used, then the delimiter specification is considered to be in the client's (that is, the control file's) character set. In this case, the delimiter is converted into the data file's character set before SQL*Loader searches for the delimiter in the data file.

Note the following:

  • Stutter syntax is supported with string delimiters (that is, the closing enclosure delimiter can be stuttered).

  • Leading whitespaces in the initial multicharacter enclosure delimiter are not allowed.

  • If a field is terminated by WHITESPACE, then the leading whitespaces are trimmed.

    Note:

    SQL*Loader defaults to 255 bytes when moving CLOB data, but a value of up to 2 gigabytes can be specified. For a delimited field, if a length is specified, then that length is used as a maximum. If no maximum is specified, then it defaults to 255 bytes. For a CHAR field that is delimited and is also greater than 255 bytes, you must specify a maximum length. See CHAR for more information about the CHAR data type.

Example 11-18 Loading LOB Data in Delimited Fields

Review this example to see how to load LOB data in delimited fields. Note the callouts in bold:

Control File Contents

LOAD DATA 
INFILE 'sample.dat' "str '|'"
INTO TABLE person_table
FIELDS TERMINATED BY ','
   (name        CHAR(25),
1  "RESUME"     CHAR(507) ENCLOSED BY '<startlob>' AND '<endlob>')

Data File (sample.dat) 

Julia Nayer,<startlob>        Julia Nayer
                          500 Example Parkway
                          jnayer@example.com ...   <endlob>
2  |Bruce Ernst, .......

Note:

The callouts, in bold, to the left of the example correspond to the following notes:

  1. <startlob> and <endlob> are the enclosure strings. With the default byte-length semantics, the maximum length for a LOB that can be read using CHAR(507) is 507 bytes. If character-length semantics were used, then the maximum would be 507 characters. For more information, refer to character-length semantics.

  2. If the record separator '|' had been placed right after <endlob> and followed with the newline character, then the newline would have been interpreted as part of the next record. An alternative would be to make the newline part of the record separator (for example, '|\n' or, in hexadecimal notation, X'7C0A').

11.4.1.3 LOB Data in Length-Value Pair Fields

To load LOB data organized in length-value pair fields, you can use VARCHAR, VARCHARC, or VARRAW data types.

Loading data with length-value pair fields provides better performance than using delimited fields. However, this method can reduce flexibility (for example, you must know the LOB length for each LOB before loading).

Example 11-19 Loading LOB Data in Length-Value Pair Fields

Review the control file and data file exmapley to see how to load LOB data in length-value pair fields. Note the callouts in bold:

Control File Contents

  LOAD DATA 
1 INFILE 'sample.dat' "str '<endrec>\n'"
  INTO TABLE person_table
  FIELDS TERMINATED BY ','
     (name       CHAR(25),
2    "RESUME"    VARCHARC(3,500))

Data File (sample.dat) 

Julia Nayer,479 Julia Nayer
500 Example Parkway
jnayer@us.example.com... <endrec>
3    Bruce Ernst,000<endrec>

Note:

The callouts in bold, to the left of the example, correspond to the following notes:

  1. If the backslash escape character is not supported, then the string used as a record separator in the example could be expressed in hexadecimal notation.

  2. "RESUME" is a field that corresponds to a CLOB column. In the control file, it is a VARCHARC, whose length field is 3 bytes long and whose maximum size is 500 bytes (with byte-length semantics). If character-length semantics were used, then the length would be 3 characters and the maximum size would be 500 characters. See Character-Length Semantics.

  3. The length subfield of the VARCHARC is 0 (the value subfield is empty). Consequently, the LOB instance is initialized to empty.

11.4.2 Loading LOB Data from LOBFILEs

LOB data can be lengthy enough so that it makes sense to load it from a LOBFILE instead of from a primary data file.

In LOBFILEs, LOB data instances are still considered to be in fields (predetermined size, delimited, length-value), but these fields are not organized into records (the concept of a record does not exist within LOBFILEs). Therefore, the processing overhead of dealing with records is avoided. This type of organization of data is ideal for LOB loading.

There is no requirement that a LOB from a LOBFILE fit in memory. SQL*Loader reads LOBFILEs in 64 KB chunks.

In LOBFILEs the data can be in any of the following types of fields:

  • A single LOB field into which the entire contents of a file can be read

  • Predetermined size fields (fixed-length fields)

  • Delimited fields (that is, TERMINATED BY or ENCLOSED BY)

    The clause PRESERVE BLANKS is not applicable to fields read from a LOBFILE.

  • Length-value pair fields (variable-length fields)

    To load data from this type of field, use the VARRAW, VARCHAR, or VARCHARC SQL*Loader data types.

See Examples of Loading LOB Data from LOBFILEs for examples of using each of these field types. All of the previously mentioned field types can be used to load XML columns.

See lobfile_spec for LOBFILE syntax.

Parent topic: Loading LOBs with SQL*Loader

11.4.2.1 Dynamic Versus Static LOBFILE Specifications

You can specify LOBFILEs either statically (the name of the file is specified in the control file) or dynamically (a FILLER field is used as the source of the file name).

In either case, if the LOBFILE is not terminated by EOF, then when the end of the LOBFILE is reached, the file is closed and further attempts to read data from that file produce results equivalent to reading data from an empty field.

However, if you have a LOBFILE that is terminated by EOF, then the entire file is always returned on each attempt to read data from that file.

You should not specify the same LOBFILE as the source of two different fields. If you do, then the two fields typically read the data independently.

11.4.2.2 Examples of Loading LOB Data from LOBFILEs

This section contains examples of loading data from different types of fields in LOBFILEs.

  • One LOB for Each File
    When you load large object type (LOB) data, each LOBFILE is the source of a single LOB.
  • Predetermined Size LOBs
    You can load LOB data using predetermined size LOBs.
  • Delimited LOBs
    When you have different sized large object types (LOBs), so you can't use predetermined size LOBs, consider using delimited LOBs with SQL*Loader.
  • Length-Value Pair Specified LOBs
    You can obtain better performance by loading large object types (LOBs) with length-value pair specification, but you lose some flexibility.

Parent topic: Loading LOB Data from LOBFILEs

11.4.2.2.1 One LOB for Each File

When you load large object type (LOB) data, each LOBFILE is the source of a single LOB.

Use this example to see how you can load LOB data that is organized so that each LOBFILE is the source of a single LOB.

Example 11-20 Loading LOB Data with One LOB per LOBFILE

In this example, note that the column or field name is followed by the LOBFILE data type specifications. Note the callouts in bold:

Control File Contents

LOAD DATA 
INFILE 'sample.dat'
   INTO TABLE person_table
   FIELDS TERMINATED BY ','
   (name      CHAR(20),
1  ext_fname    FILLER CHAR(40),
2  "RESUME"     LOBFILE(ext_fname) TERMINATED BY EOF)

Data File (sample.dat) 

Johny Quest,jqresume.txt,
Speed Racer,'/private/sracer/srresume.txt',

Secondary Data File (jqresume.txt)

Johny Quest 500 Oracle Parkway ...

Secondary Data File (srresume.txt) 

         Speed Racer
     400 Oracle Parkway
        ...

Note:

The callouts in bold, to the left of the example, correspond to the following notes:

  1. The filler field is mapped to the 40-byte data field, which is read using the SQL*Loader CHAR data type. This assumes the use of default byte-length semantics. If character-length semantics were used, then the field would be mapped to a 40-character data field

  2. SQL*Loader gets the LOBFILE name from the ext_fname filler field. It then loads the data from the LOBFILE (using the CHAR data type) from the first byte to the EOF character. If no existing LOBFILE is specified, then the "RESUME" field is initialized to empty.

11.4.2.2.2 Predetermined Size LOBs

You can load LOB data using predetermined size LOBs.

In Example 11-21, you specify the size of the LOBs to be loaded into a particular column in the control file. During the load, SQL*Loader assumes that any LOB data loaded into that particular column is of the specified size. The predetermined size of the fields allows the data-parser to perform optimally. However, it is often difficult to guarantee that all LOBs are the same size.

Example 11-21 Loading LOB Data Using Predetermined Size LOBs

Control File Contents

LOAD DATA 
INFILE 'sample.dat'
INTO TABLE person_table
FIELDS TERMINATED BY ','
   (name     CHAR(20),
1  "RESUME"    LOBFILE(CONSTANT '/usr/private/jquest/jqresume.txt')
               CHAR(2000))

Data File (sample.dat)

Johny Quest,
Speed Racer,

Secondary Data File (jqresume.txt)

             Johny Quest
         500 Oracle Parkway
            ...
             Speed Racer
         400 Oracle Parkway
            ...

Note:

The callout, in bold, to the left of the example corresponds to the following note:

  1. This entry specifies that SQL*Loader load 2000 bytes of data from the jqresume.txt LOBFILE, using the CHAR data type, starting with the byte following the byte loaded last during the current loading session. This assumes the use of the default byte-length semantics. If character-length semantics were used, then SQL*Loader would load 2000 characters of data, starting from the first character after the last-loaded character. See Character-Length Semantics.

11.4.2.2.3 Delimited LOBs

When you have different sized large object types (LOBs), so you can't use predetermined size LOBs, consider using delimited LOBs with SQL*Loader.

When you load LOB data instances that are delimited, loading different size LOBs into the same column is not a problem. However, this added flexibility can affect performance, because SQL*Loader must scan through the data, looking for the delimiter string.

Example 11-22 Loading LOB Data Using Delimited LOBs

In this example, note the callouts in bold:

Control File Contents

LOAD DATA 
INFILE 'sample.dat'
INTO TABLE person_table
FIELDS TERMINATED BY ','
   (name     CHAR(20),
1  "RESUME"    LOBFILE( CONSTANT 'jqresume') CHAR(2000) 
               TERMINATED BY "<endlob>\n")

Data File (sample.dat)

Johny Quest,
Speed Racer,

Secondary Data File (jqresume.txt)

             Johny Quest
         500 Oracle Parkway
            ... <endlob>
             Speed Racer
         400 Oracle Parkway
            ... <endlob>

Note:

The callout, in bold, to the left of the example corresponds to the following note:

  1. Because a maximum length of 2000 is specified for CHAR, SQL*Loader knows what to expect as the maximum length of the field, which can result in memory usage optimization. If you choose to specify a maximum length, then you should be sure not to underestimate its value. The TERMINATED BY clause specifies the string that terminates the LOBs. Alternatively, you can use the ENCLOSED BY clause. The ENCLOSED BY clause allows a bit more flexibility with the relative positioning of the LOBs in the LOBFILE, because the LOBs in the LOBFILE do not need to be sequential.

11.4.2.2.4 Length-Value Pair Specified LOBs

You can obtain better performance by loading large object types (LOBs) with length-value pair specification, but you lose some flexibility.

With length-value pair specified LOBs, each LOB in the LOBFILE is preceded by its length. To load LOB data organized in this way, you can use VARCHAR, VARCHARC, or VARRAW data types.

This method of loading can provide better performance over delimited LOBs, but at the expense of some flexibility (for example, you must know the LOB length for each LOB before loading).

Example 11-23 Loading LOB Data Using Length-Value Pair Specified LOBs

Control File Contents

In the following example, note the callouts in bold: 

LOAD DATA 
INFILE 'sample.dat'
INTO TABLE person_table
FIELDS TERMINATED BY ','
   (name          CHAR(20),
1  "RESUME"       LOBFILE(CONSTANT 'jqresume') VARCHARC(4,2000))

Data File (sample.dat) 

Johny Quest,
Speed Racer,

Secondary Data File (jqresume.txt) 

2      0501Johny Quest
       500 Oracle Parkway
          ... 
3      0000

Note:

The callouts, in bold, to the left of the example correspond to the following notes:

  1. The entry VARCHARC(4,2000) tells SQL*Loader that the LOBs in the LOBFILE are in length-value pair format and that the first 4 bytes should be interpreted as the length. The value of 2000 tells SQL*Loader that the maximum size of the field is 2000 bytes. This assumes the use of the default byte-length semantics. If character-length semantics were used, then the first 4 characters would be interpreted as the length in characters. The maximum size of the field would be 2000 characters. See Character-Length Semantics.

  2. The entry 0501 preceding Johny Quest tells SQL*Loader that the LOB consists of the next 501 characters.

  3. This entry specifies an empty (not null) LOB.

11.4.2.3 Considerations When Loading LOBs from LOBFILEs

Be aware of the restrictions and guidelines that apply when you load large object types (LOBs) from LOBFILES with SQL*Loader.

When you load data using LOBFILEs, be aware of the following:

  • Only LOBs and XML columns can be loaded from LOBFILEs.

  • The failure to load a particular LOB does not result in the rejection of the record containing that LOB. Instead, the result is a record that contains an empty LOB. In the case of an XML column, if there is a failure loading the LOB. then a null value is inserted.

  • It is not necessary to specify the maximum length of a field corresponding to a LOB column. If a maximum length is specified, then SQL*Loader uses it as a hint to optimize memory usage. Therefore, it is important that the maximum length specification does not understate the true maximum length.

  • You cannot supply a position specification (pos_spec) when loading data from a LOBFILE.

  • NULLIF or DEFAULTIF field conditions cannot be based on fields read from LOBFILEs.

  • If a nonexistent LOBFILE is specified as a data source for a particular field, then that field is initialized to empty. If the concept of empty does not apply to the particular field type, then the field is initialized to null.

  • Table-level delimiters are not inherited by fields that are read from a LOBFILE.

  • When loading an XML column or referencing a LOB column in a SQL expression in conventional path mode, SQL*Loader must process the LOB data as a temporary LOB. To ensure the best load performance possible in these cases, refer to the guidelines for temporary LOB performance.

11.4.3 Loading Data Files that Contain LLS Fields

If a field in a data file is a LOB location Specifier (LLS) field, then you can indicate this by using the LLS clause.

Purpose

An LLS field contains the file name, offset, and length of the LOB data in the data file. SQL*Loader uses this information to read data for the LOB column.

Syntax

The syntax for the LLS clause is as follows:

Description of lls_field_spec.eps follows
Description of the illustration lls_field_spec.eps

Usage Notes

The LOB can be loaded in part or in whole and it can start from an arbitrary position and for an arbitrary length. SQL Loader expects the expects the contents of the LLS field to be filename.ext.nnn.mmm/ where each element is defined as follows:

  • filename.ext is the name of the file that contains the LOB.

  • nnn is the offset in bytes of the LOB within the file.

  • mmm is the length of the LOB in bytes. A value of -1 means the LOB is NULL. A value of 0 means the LOB exists, but is empty.

  • The forward slash (/) terminates the field

If the SQL*Loader parameter, SDF_PREFIX, is specified, then SQL*Loader looks for the files in the directory specified by SDF_PREFIX. Otherwise, SQL*Loader looks in the same directory as the data file.

An error is reported and the row is rejected if any of the following are true:

  • The file name contains a relative or absolute path specification.

  • The file is not found, the offset is invalid, or the length extends beyond the end of the file.

  • The contents of the field do not match the expected format.

  • The data type for the column associated with an LLS field is not a CLOB, BLOB, or NCLOB.

Restrictions

  • If an LLS field is referenced by a clause for any other field (for example a NULLIF clause) in the control file, then the value used for evaluating the clause is the string in the data file, not the data in the file pointed to by that string.

  • The character set for the data in the file pointed to by the LLS clause is assumed to be the same character set as the data file.

  • The user running SQL*Loader must have read access to the data files.

Example Specification of an LLS Clause

The following is an example of a SQL*Loader control file that contains an LLS clause. Note that a data type is not needed on the column specification because the column must be of type LOB. 

LOAD DATA
INFILE *
TRUNCATE
INTO TABLE tklglls
FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"' TRAILING NULLCOLS
(col1 , col2 NULLIF col1 = '1' LLS)
BEGINDATA
1,"tklglls1.dat.1.11/"

Parent topic: Loading LOBs with SQL*Loader

11.5 Loading BFILE Columns with SQL*Loader

The BFILE data type stores unstructured binary data in operating system files outside the database.

The Oracle BFILE data type is an Oracle LOB data type that contains a reference to binary data with a maximum size of 4 gigabytes.

A BFILE column or attribute stores a file locator that points to the external file containing the data. The file that you want to load as a BFILE does not have to exist at the time of loading; it can be created later. To use BFILEs, you must peform some database administration tasks. There are also restrictions on directory objects and BFILE objects. These restrictions include requirements for how you configure the operating system file, and the operating system directory path. With Oracle Database 18c and later releases, symbolic links are not allowed in directory object path names used with BFILE data types. SQL*Loader assumes that the necessary directory objects are already created (a logical alias name for a physical directory on the server's file system).

A control file field corresponding to a BFILE column consists of a column name, followed by the BFILE clause. The BFILE clause takes as arguments a directory object (the server_directory alias) name, followed by a BFILE name. You can provide both arguments as string constants, or these arguments can be dynamically loaded through some other field.

In the following examples of loading BFILEs, the first example has only the file name specified dynamically, while the second example demonstrates specifying both the BFILE and the directory object dynamically:

Example 11-24 Loading Data Using BFILEs: Only File Name Specified Dynamically

The following are the control file contents. The directory name, scott_dir1, is in quotation marks; therefore, the string is used as is, and is not capitalized. 

LOAD DATA
INFILE sample.dat
INTO TABLE planets
FIELDS TERMINATED BY ','
   (pl_id    CHAR(3), 
   pl_name   CHAR(20),
   fname     FILLER CHAR(30),
   pl_pict   BFILE(CONSTANT "scott_dir1", fname))

The following are the contents of the data file, sample.dat. 

1,Mercury,mercury.jpeg,
2,Venus,venus.jpeg,
3,Earth,earth.jpeg,

Example 11-25 Loading Data Using BFILEs: File Name and Directory Specified Dynamically

The following are the control file contents. Note that dname is mapped to the data file field containing the directory name that corresponds to the file being loaded. 

LOAD DATA
INFILE sample.dat
INTO TABLE planets
FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
   (pl_id    NUMBER(4), 
   pl_name   CHAR(20), 
   fname     FILLER CHAR(30),
   dname     FILLER CHAR(20),
   pl_pict   BFILE(dname, fname) )

The following are the contents of the data file, sample.dat. 

1, Mercury, mercury.jpeg, scott_dir1,
2, Venus, venus.jpeg, scott_dir1,
3, Earth, earth.jpeg, scott_dir2,

Related Topics

Parent topic: Loading Objects, LOBs, and Collections with SQL*Loader

11.6 Loading Collections (Nested Tables and VARRAYs)

Like LOBs, collections can be loaded either from a primary data file (data inline) or from secondary data files (data out of line).

When you load collection data, a mechanism must exist by which SQL*Loader can tell when the data belonging to a particular collection instance has ended. You can achieve this in two ways:

  • To specify the number of rows or elements that are to be loaded into each nested table or VARRAY instance, use the DDL COUNT function. The value specified for COUNT must either be a number or a character string containing a number, and it must be previously described in the control file before the COUNT clause itself. This positional dependency is specific to the COUNT clause. COUNT(0) or COUNT(cnt_field), where cnt_field is 0 for the current row, results in a empty collection (not null), unless overridden by a NULLIF clause. See count_spec.

    If the COUNT clause specifies a field in a control file and if that field is set to null for the current row, then the collection that uses that count will be set to empty for the current row as well.

  • Use the TERMINATED BY and ENCLOSED BY clauses to specify a unique collection delimiter. This method cannot be used if an SDF clause is used.

In the control file, collections are described similarly to column objects. There are some differences:

  • Collection descriptions employ the two mechanisms discussed in the preceding list.

  • Collection descriptions can include a secondary data file (SDF) specification.

  • A NULLIF or DEFAULTIF clause cannot refer to a field in an SDF unless the clause is on a field in the same SDF.

  • Clauses that take field names as arguments cannot use a field name that is in a collection unless the DDL specification is for a field in the same collection.

  • The field list must contain only one nonfiller field and any number of filler fields. If the VARRAY is a VARRAY of column objects, then the attributes of each column object will be in a nested field list.

See Also:

For details about SDFs, see Secondary Data Files (SDFs).

For details about loading column objects, see Loading Column Objects.

Parent topic: Loading Objects, LOBs, and Collections with SQL*Loader

11.6.1 Restrictions in Nested Tables and VARRAYs

There are restrictions for nested tables and VARRAYs.

The following restrictions exist for nested tables and VARRAYs:

  • A field_list cannot contain a collection_fld_spec.

  • A col_obj_spec nested within a VARRAY cannot contain a collection_fld_spec.

  • The column_name specified as part of the field_list must be the same as the column_name preceding the VARRAY parameter.

Also, be aware that if you are loading into a table containing nested tables, then SQL*Loader will not automatically split the load into multiple loads and generate a set ID.

Example 11-26 demonstrates loading a VARRAY and a nested table.

Example 11-26 Loading a VARRAY and a Nested Table

Control File Contents

   LOAD DATA
   INFILE 'sample.dat' "str '\n' "
   INTO TABLE dept
   REPLACE
   FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
   (
     dept_no       CHAR(3),
     dname         CHAR(25) NULLIF dname=BLANKS,
1    emps          VARRAY TERMINATED BY ':'
     (
       emps        COLUMN OBJECT
       (
         name      CHAR(30),
         age       INTEGER EXTERNAL(3),
2        emp_id    CHAR(7) NULLIF emps.emps.emp_id=BLANKS
     )
   ),
3   proj_cnt      FILLER CHAR(3),
4   projects      NESTED TABLE SDF (CONSTANT "pr.txt" "fix 57") COUNT (proj_cnt)
  (
    projects    COLUMN OBJECT
    (
      project_id        POSITION (1:5) INTEGER EXTERNAL(5),
      project_name      POSITION (7:30) CHAR 
                        NULLIF projects.projects.project_name = BLANKS
    )
  )
)

Data File (sample.dat)

 101,MATH,"Napier",28,2828,"Euclid", 123,9999:0
 210,"Topological Transforms",:2

Secondary Data File (SDF) (pr.txt)

21034 Topological Transforms
77777 Impossible Proof

Note:

The callouts, in bold, to the left of the example correspond to the following notes:

  1. The TERMINATED BY clause specifies the VARRAY instance terminator (note that no COUNT clause is used).

  2. Full name field references (using dot notation) resolve the field name conflict created by the presence of this filler field.

  3. proj_cnt is a filler field used as an argument to the COUNT clause.

  4. This entry specifies the following:

    • An SDF called pr.txt as the source of data. It also specifies a fixed-record format within the SDF.

    • If COUNT is 0, then the collection is initialized to empty. Another way to initialize a collection to empty is to use a DEFAULTIF clause. The main field name corresponding to the nested table field description is the same as the field name of its nested nonfiller-field, specifically, the name of the column object field description.

Parent topic: Loading Collections (Nested Tables and VARRAYs)

11.6.2 Secondary Data Files (SDFs)

When you need to load large nested tables and VARRAYs, you can use secondary data files (SDFs). They are similar in concept to primary data files.

As with primary data files, SDFs are a collection of records, and each record is made up of fields. The SDFs are specified on a per control-file-field basis. They are useful when you load large nested tables and VARRAYs.

Note:

Only a collection_fld_spec can name an SDF as its data source.

SDFs are specified using the SDF parameter. The SDF parameter can be followed by either the file specification string, or a FILLER field that is mapped to a data field containing one or more file specification strings.

As for a primary data file, the following can be specified for each SDF:

  • The record format (fixed, stream, or variable). Also, if stream record format is used, then you can specify the record separator.

  • The record size.

  • The character set for an SDF can be specified using the CHARACTERSET clause (see Handling Different Character Encoding Schemes).

  • A default delimiter (using the delimiter specification) for the fields that inherit a particular SDF specification (all member fields or attributes of the collection that contain the SDF specification, with exception of the fields containing their own LOBFILE specification).

Also note the following regarding SDFs:

  • If a nonexistent SDF is specified as a data source for a particular field, then that field is initialized to empty. If the concept of empty does not apply to the particular field type, then the field is initialized to null.

  • Table-level delimiters are not inherited by fields that are read from an SDF.

  • To load SDFs larger than 64 KB, you must use the READSIZE parameter to specify a larger physical record size. You can specify the READSIZE parameter either from the command line or as part of an OPTIONS clause.

    See Also:

Parent topic: Loading Collections (Nested Tables and VARRAYs)

11.7 Choosing Dynamic or Static SDF Specifications

With SQL*Loader, you can specify SDFs either statically (specifying the actual name of the file), or dynamically (using a FILLER field as the source of the file name).

With either dynamic or static SDF specification, when the end-of-file (EOF) of an SDF is reached, the file is closed. Further attempts to reading data from that particular file produce results equivalent to reading data from an empty field.

In a dynamic secondary file specification, this behavior is slightly different. When the specification changes to reference a new file, the old file is closed, and the data is read from the beginning of the newly referenced file.

Fynamic switching of the data source files has a resetting effect. For example, when SQL*Loader switches from the current file to a previously opened file, the previously opened file is reopened, and the data is read from the beginning of the file.

You should not specify the same SDF as the source of two different fields. If you do, then the two fields typically read the data independently.

Parent topic: Loading Objects, LOBs, and Collections with SQL*Loader

11.8 Loading a Parent Table Separately from Its Child Table

When you load a table that contains a nested table column, it may be possible to load the parent table separately from the child table.

You can load the parent and child tables independently if the SIDs (system-generated or user-defined) are already known at the time of the load (that is, the SIDs are in the data file with the data).

The following examples illustrate how to load parent and child tables with user-provided SIDs.

Example 11-27 Loading a Parent Table with User-Provided SIDs

Control File Contents

   LOAD DATA
   INFILE 'sample.dat' "str '|\n' "
   INTO TABLE dept
   FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
   TRAILING NULLCOLS
   ( dept_no   CHAR(3),
   dname       CHAR(20) NULLIF dname=BLANKS ,
   mysid       FILLER CHAR(32),
1  projects    SID(mysid))

Data File (sample.dat)

101,Math,21E978407D4441FCE03400400B403BC3,|
210,"Topology",21E978408D4441FCE03400400B403BC3,|

Note:

The callout, in bold, to the left of the example corresponds to the following note:

  1. mysid is a filler field that is mapped to a data file field containing the actual set IDs and is supplied as an argument to the SID clause.

Example 11-28 Loading a Child Table with User-Provided SIDs

Control File Contents    

   LOAD DATA
   INFILE 'sample.dat'
   INTO TABLE dept
   FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
   TRAILING NULLCOLS
1  SID(sidsrc)
   (project_id     INTEGER EXTERNAL(5),
   project_name   CHAR(20) NULLIF project_name=BLANKS,
   sidsrc FILLER  CHAR(32))

Data File (sample.dat)

21034, "Topological Transforms", 21E978407D4441FCE03400400B403BC3,
77777, "Impossible Proof", 21E978408D4441FCE03400400B403BC3,

Note:

The callout, in bold, to the left of the example corresponds to the following note:

  1. The table-level SID clause tells SQL*Loader that it is loading the storage table for nested tables. sidsrc is the filler field name that is the source of the real set IDs.

Parent topic: Loading Objects, LOBs, and Collections with SQL*Loader

11.8.1 Memory Issues When Loading VARRAY Columns

There are some memory issues when you load VARRAY columns.

The following list describes some issues to keep in mind when you load VARRAY columns:

  • VARRAYs are created in the client's memory before they are loaded into the database. Each element of a VARRAY requires 4 bytes of client memory before it can be loaded into the database. Therefore, when you load a VARRAY with a thousand elements, you will require at least 4000 bytes of client memory for each VARRAY instance before you can load the VARRAYs into the database. In many cases, SQL*Loader requires two to three times that amount of memory to successfully construct and load a VARRAY.

  • The BINDSIZE parameter specifies the amount of memory allocated by SQL*Loader for loading records. Given the value specified for BINDSIZE, SQL*Loader takes into consideration the size of each field being loaded, and determines the number of rows it can load in one transaction. The larger the number of rows, the fewer transactions, resulting in better performance. But if the amount of memory on your system is limited, then at the expense of performance, you can specify a lower value for ROWS than SQL*Loader calculated.

  • Loading very large VARRAYs or a large number of smaller VARRAYs could cause you to run out of memory during the load. If this happens, then specify a smaller value for BINDSIZE or ROWS and retry the load.

Parent topic: Loading a Parent Table Separately from Its Child Table