pg_attrdef

The pg_attrdef table stores column default values. The main information about columns is stored in pg_attribute. Only columns that explicitly specify a default value (when the table is created or the column is added) will have an entry here.

column	type	references	description
oid	oid		The object ID
adrelid	oid	pg_class.oid	The table this column belongs to
adnum	smallint	pg_attribute.attnum	The number of the column
adbin	pg_node_tree		The internal representation of the column default value

Parent topic: System Catalogs Definitions