|Oracle® Database PL/SQL User's Guide and Reference
10g Release 2 (10.2)
|PDF · Mobi · ePub|
UPDATE statement changes the values of specified columns in one or more rows in a table or view. For a full description of the
UPDATE SQL statement, see Oracle Database SQL Reference.
update statement ::=
Another (usually short) name for the referenced table or view, typically used in the
The column (or one of the columns) to be updated. It must be the name of a column in the referenced table or view. A column name cannot be repeated in the
column_name list. Column names need not appear in the
UPDATE statement in the same order that they appear in the table or view.
Returns values from updated rows, eliminating the need to
SELECT the rows afterward. You can retrieve the column values into variables or host variables, or into collections or host arrays. You cannot use the
RETURNING clause for remote or parallel updates. If the statement does not affect any rows, the values of the variables specified in the
RETURNING clause are undefined. For the syntax of
returning_clause, see "RETURNING INTO Clause".
This clause assigns the value of
sql_expression to the column identified by
sql_expression contains references to columns in the table being updated, the references are resolved in the context of the current row. The old column values are used on the right side of the equal sign.
SET column_name = (subquery3)
Assigns the value retrieved from the database by
subquery3 to the column identified by
column_name. The subquery must return exactly one row and one column.
SET (column_name, column_name, ...) = (subquery4)
Assigns the values retrieved from the database by
subquery4 to the columns in the
column_name list. The subquery must return exactly one row that includes all the columns listed. The column values returned by the subquery are assigned to the columns in the column list in order. The first value is assigned to the first column in the list, the second value is assigned to the second column in the list, and so on.
Any valid SQL expression. For more information, see Oracle Database SQL Reference.
SELECT statement that provides a set of rows for processing. Its syntax is like that of
select_into_statement without the
INTO clause. See "SELECT INTO Statement".
A table or view that must be accessible when you execute the
UPDATE statement, and for which you must have
UPDATE privileges. For the syntax of
table_reference, see "DELETE Statement".
The operand of
TABLE is a
SELECT statement that returns a single column value, which must be a nested table or a varray. Operator
TABLE informs Oracle that the value is a collection, not a scalar value.
Refers to the latest row processed by the
FETCH statement associated with the specified cursor. The cursor must be
UPDATE and must be open and positioned on a row. If the cursor is not open, the
OF clause causes an error. If the cursor is open, but no rows have been fetched or the last fetch returned no rows, PL/SQL raises the predefined exception
Chooses which rows to update in the database table. Only rows that meet the search condition are updated. If you omit this clause, all rows in the table are updated.
You can use the
OF statement after a fetch from an open cursor (including fetches done by a cursor
FOR loop), provided the associated query is
UPDATE. This statement updates the row that was just fetched.
The implicit cursor
SQL and the cursor attributes
%ISOPEN let you access useful information about the execution of an
Example 13-7 creates a table with correct employee IDs but garbled names. Then it runs an
UPDATE statement with a correlated query, to retrieve the correct names from the
EMPLOYEES table and fix the names in the new table.
-- Create a table with all the right IDs, but messed-up names CREATE TABLE employee_temp AS SELECT employee_id, UPPER(first_name) first_name, TRANSLATE(last_name,'aeiou','12345') last_name FROM employees; BEGIN -- Display the first 5 names to show they're messed up FOR person IN (SELECT * FROM employee_temp WHERE ROWNUM < 6) LOOP DBMS_OUTPUT.PUT_LINE(person.first_name || ' ' || person.last_name); END LOOP; UPDATE employee_temp SET (first_name, last_name) = (SELECT first_name, last_name FROM employees WHERE employee_id = employee_temp.employee_id); DBMS_OUTPUT.PUT_LINE('*** Updated ' || SQL%ROWCOUNT || ' rows. ***'); -- Display the first 5 names to show they've been fixed up FOR person IN (SELECT * FROM employee_temp WHERE ROWNUM < 6) LOOP DBMS_OUTPUT.PUT_LINE(person.first_name || ' ' || person.last_name); END LOOP; END; /
For examples, see the following: