SET CONSTRAINTS { ALL | constraint[,... ]} {DEFERRED | IMMEDIATE}
Use this keyword to indicate that the mode you are specifying should be applied to all constraints within the current transaction.
Use this parameter to supply the name of a specific constraint you wish to set the mode of.
Use this keyword to indicate that constraints (or a specific constraint) shouldn't be checked until the transaction reaches a COMMIT.
Use this keyword to indicate that constraints (or a specific constraint) should be checked at the end of each statement within a transaction.
Use the SET CONSTRAINTS command to set the constraint mode for all constraints within the current transaction block (or a single constraint, if specified). You can choose to set it to either IMMEDIATE mode or DEFERRED mode. IMMEDIATE mode will force the checking of all constraints at the end of each statement within the transaction. In DEFERRED mode, constraints are not checked until a COMMIT command is issued.
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PostgreSQL 7.1.x (the most current version as of the writing of this book) only supports the use of these modes with foreign key constraints, as both check and unique constraints are set to a constraint mode that is not affected by this command. |