UPDATE

Name

UPDATE -- update rows of a table

Synopsis

UPDATE [ <optimizer_hint> ] <table>[@<dblink> ]
    SET <column> = { <expression> | DEFAULT } [, ...]
  [ WHERE <condition> ]
  [ RETURNING <return_expression> [, ...]
      { INTO { <record> | <variable> [, ...] }
      | BULK COLLECT INTO <collection> [, ...] } ]

Description

UPDATE changes the values of the specified columns in all rows that satisfy the condition. Only the columns to be modified need be mentioned in the SET clause; columns not explicitly modified retain their previous values.

The RETURNING INTO { record | variable [, ...] } clause may only be specified within an SPL program. In addition the result set of the UPDATE command must not return more than one row, otherwise an exception is thrown. If the result set is empty, then the contents of the target record or variables are set to null.

The RETURNING BULK COLLECT INTO collection [, ...] clause may only be specified if the UPDATE command is used within an SPL program. If more than one collection is specified as the target of the BULK COLLECT INTO clause, then each collection must consist of a single, scalar field – i.e., collection must not be a record. The result set of the UPDATE command may contain none, one, or more rows. return_expression evaluated for each row of the result set, becomes an element in collection starting with the first element. Any existing rows in collection are deleted. If the result set is empty, then collection will be empty.

You must have the UPDATE privilege on the table to update it, as well as the SELECT privilege to any table whose values are read in expression or condition.

Parameters

optimizer_hint

Comment-embedded hints to the optimizer for selection of an execution plan.

table

The name (optionally schema-qualified) of the table to update.

dblink

Database link name identifying a remote database. See the CREATE DATABASE LINK command for information on database links.

column

The name of a column in table.

expression

An expression to assign to the column. The expression may use the old values of this and other columns in the table.

DEFAULT

Set the column to its default value (which will be null if no specific default expression has been assigned to it).

condition

An expression that returns a value of type BOOLEAN. Only rows for which this expression returns true will be updated.

return_expression

An expression that may include one or more columns from table. If a column name from table is specified in return_expression, the value substituted for the column when return_expression is evaluated is determined as follows:

If the column specified in return_expression is assigned a value in the UPDATE command, then the assigned value is used in the evaluation of return_expression.

If the column specified in return_expression is not assigned a value in the UPDATE command, then the column’s current value in the affected row is used in the evaluation of return_expression.

record

A record whose field the evaluated return_expression is to be assigned. The first return_expression is assigned to the first field in record, the second return_expression is assigned to the second field in record, etc. The number of fields in record must exactly match the number of expressions and the fields must be type-compatible with their assigned expressions.

variable

A variable to which the evaluated return_expression is to be assigned. If more than one return_expression and variable are specified, the first return_expression is assigned to the first variable, the second return_expression is assigned to the second variable, etc. The number of variables specified following the INTO keyword must exactly match the number of expressions following the RETURNING keyword and the variables must be type-compatible with their assigned expressions.

collection

A collection in which an element is created from the evaluated return_expression. There can be either a single collection which may be a collection of a single field or a collection of a record type, or there may be more than one collection in which case each collection must consist of a single field. The number of return expressions must match in number and order the number of fields in all specified collections. Each corresponding return_expression and collection field must be type-compatible.

Examples

Change the location to AUSTIN for department 20 in the dept table:

UPDATE dept SET loc = 'AUSTIN' WHERE deptno = 20;

For all employees with job = SALESMAN in the emp table, update the salary by 10% and increase the commission by 500.

UPDATE emp SET sal = sal * 1.1, comm = comm + 500 WHERE job = 'SALESMAN';