Table Constraint

Description

A table constraint definition is not tied to a particular column, and it can encompass more than one column.

Click here to navigate to the Greenplum documentation page for this syntax.

Grammar Syntax

[ CONSTRAINT <constraint_name> ]
{ CHECK ( <expression> ) [ NO INHERIT ]
  | UNIQUE ( <column_name> [, ... ] ) <index_parameters>
  | PRIMARY KEY ( <column_name> [, ... ] ) <index_parameters>
  | FOREIGN KEY ( <column_name> [, ... ] ) 
      REFERENCES <reftable> [ ( <refcolumn> [, ... ] ) ]
      [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ] 
      [ ON DELETE <key_action> ] [ ON UPDATE <key_action> ] }
[ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]

For more in deep information about table constraint, you can refer to PostgreSQL table constraints.