| domain_catalog | sql_identifier | Name of the database that contains the domain (always the current database) | 
| domain_schema | sql_identifier | Name of the schema that contains the domain | 
| domain_name | sql_identifier | Name of the domain | 
| data_type | character_data | Data type of the domain, if it is a built-in type, or
       ARRAY if it is some array (in that case, see
       the view element_types), else
       USER-DEFINED (in that case, the type is
       identified in udt_name and associated
       columns). | 
| character_maximum_length | cardinal_number | If the domain has a character or bit string type, the declared
       maximum length; null for all other data types or if no maximum
       length was declared. | 
| character_octet_length | cardinal_number | If the domain has a character type, the maximum possible length
       in octets (bytes) of a datum (this should not be of concern to
       PostgreSQL users); null for all
       other data types. | 
| character_set_catalog | sql_identifier | Applies to a feature not available in PostgreSQL | 
| character_set_schema | sql_identifier | Applies to a feature not available in PostgreSQL | 
| character_set_name | sql_identifier | Applies to a feature not available in PostgreSQL | 
| collation_catalog | sql_identifier | Applies to a feature not available in PostgreSQL | 
| collation_schema | sql_identifier | Applies to a feature not available in PostgreSQL | 
| collation_name | sql_identifier | Applies to a feature not available in PostgreSQL | 
| numeric_precision | cardinal_number | If the domain has a numeric type, this column contains the
       (declared or implicit) precision of the type for this column.
       The precision indicates the number of significant digits.  It
       may be expressed in decimal (base 10) or binary (base 2) terms,
       as specified in the column
       numeric_precision_radix.  For all other data
       types, this column is null. | 
| numeric_precision_radix | cardinal_number | If the domain has a numeric type, this column indicates in
       which base the values in the columns
       numeric_precision and
       numeric_scale are expressed.  The value is
       either 2 or 10.  For all other data types, this column is null. | 
| numeric_scale | cardinal_number | If the domain has an exact numeric type, this column contains
       the (declared or implicit) scale of the type for this column.
       The scale indicates the number of significant digits to the
       right of the decimal point.  It may be expressed in decimal
       (base 10) or binary (base 2) terms, as specified in the column
       numeric_precision_radix.  For all other data
       types, this column is null. | 
| datetime_precision | cardinal_number | If the domain has a date, time, or interval type, the declared
       precision; null for all other data types or if no precision was
       declared. | 
| interval_type | character_data | Not yet implemented | 
| interval_precision | character_data | Not yet implemented | 
| domain_default | character_data | Default expression of the domain | 
| udt_catalog | sql_identifier | Name of the database that the domain data type is defined in (always the current database) | 
| udt_schema | sql_identifier | Name of the schema that the domain data type is defined in | 
| udt_name | sql_identifier | Name of the domain data type | 
| scope_catalog | sql_identifier | Applies to a feature not available in PostgreSQL | 
| scope_schema | sql_identifier | Applies to a feature not available in PostgreSQL | 
| scope_name | sql_identifier | Applies to a feature not available in PostgreSQL | 
| maximum_cardinality | cardinal_number | Always null, because arrays always have unlimited maximum cardinality in PostgreSQL | 
| dtd_identifier | sql_identifier | An identifier of the data type descriptor of the domain, unique
       among the data type descriptors pertaining to the domain (which
       is trivial, because a domain only contains one data type
       descriptor).  This is mainly useful for joining with other
       instances of such identifiers.  (The specific format of the
       identifier is not defined and not guaranteed to remain the same
       in future versions.) |