PG_ATTRDEF

PG_ATTRDEF records default values of columns.

**Table 1** PG_ATTRDEF columns
Name	Type	Description
oid	oid	Row identifier (hidden attribute, which must be specified).
adrelid	oid	Table to which a column belongs
adnum	smallint	Number of columns
adbin	pg_node_tree	Internal representation of the default value of the column
adsrc	text	Internal representation of the human-readable default value
adgencol	"char"	Specifies whether a column is a generated column. The value 's' indicates that the column is a generated column, and the value '\0' indicates that the column is a common column. The default value is '\0'.
adbin_on_update	pg_node_tree	Internal representation of the attribute expression on update current_timestamp of the column.
adsrc_on_update	text	Internal representation of the readable attribute expression on update current_timestamp.