PostgreSQL 7.2.1 Documentation
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# SET CONSTRAINTS

## Name

SET CONSTRAINTS -- set the constraint mode of the current transaction

## Synopsis

    SET CONSTRAINTS { ALL | constraint [, ...] } { DEFERRED | IMMEDIATE }

## Description

SET CONSTRAINTS sets the behavior of constraint evaluation in the current transaction. In `IMMEDIATE` mode, constraints are checked at the end of each statement. In `DEFERRED` mode, constraints are not checked until transaction commit.

Upon creation, a constraint is always give one of three characteristics: `INITIALLY DEFERRED`, `INITIALLY IMMEDIATE DEFERRABLE`, or `INITIALLY IMMEDIATE NOT DEFERRABLE`. The third class is not affected by the SET CONSTRAINTS command.

Currently, only foreign key constraints are affected by this setting. Check and unique constraints are always effectively initially immediate not deferrable.

## Compatibility

### SQL92, SQL99

SET CONSTRAINT is defined in SQL92 and SQL99.

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