Extended Syntax

MogDB provides extended syntax .

Table 1 Extended SQL syntax

Category	Keywords	Description
Creating a table	INHERITS ( parent_table [, … ] )	Specifies whether an inherited table is supported.
	column_constraint： REFERENCES reftable [ ( refcolumn ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ][ ON DELETE action ] [ ON UPDATE action ]	You can run REFERENCES reftable[(refcolumn)] [MATCH FULL |MATCH PARTIAL | MATCH SIMPLE] [ON DELETE action] [ON UPDATE action] to create foreign key constraints for tables.
Loading a module	CREATE EXTENSION	Loads a new module (such as DBLINK) to the current database.
	DROP EXTENSION	Deletes the loaded module.
Aggregate functions	CREATE AGGREGATE	Defines a new aggregation function.
	ALTER AGGREGATE	Modifies the definition of an aggregate function.
	DROP AGGREGATE	Drops an existing function.