pg_attrdef
The catalog pg_attrdef stores column default values. The main information about columns is stored in pg_attribute. Only columns for which a default value has been explicitly set will have an entry here.
pg_attrdef Columns
| Column Type | Description |
|---|---|
oid oid | Row identifier |
adrelid oid (references pg_class.oid) | The table this column belongs to |
adnum int2 (references pg_attribute.attnum) | The number of the column |
adbin pg_node_tree | The column default value, in nodeToString() representation. Use pg_get_expr(adbin, adrelid) to convert it to an SQL expression. |