This catalog stores column default values. The main information about columns is stored in pg_attribute (see below). Only columns that explicitly specify a default value (when the table is created or the column is added) will have an entry here.
Table 3-3. pg_attrdef Columns
| Name | Type | References | Description |
|---|---|---|---|
| adrelid | oid | pg_class.oid | The table this column belongs to |
| adnum | int2 | The number of the column; see pg_attribute.pg_attnum | |
| adbin | text | An internal representation of the column default value | |
| adsrc | text | A human-readable representation of the default value |
Read the upstream documentation. For corrections, first check the current version.