information schema

Does anybody know why "key_column_usage", and
"referential_constraints" are empty in
information_schema? Have these been implemented?

e.g.
cms=# select * from
information_schema.key_column_usage;
constraint_catalog | constraint_schema |
constraint_name | table_catalog | table_schema |
table_name | column_name | ordinal_position
--------------------+-------------------+-----------------+---------------+--------------+------------+-------------+------------------
(0 rows)

cms=# select * from
information_schema.referential_constraints;
constraint_catalog | constraint_schema |
constraint_name | unique_constraint_catalog |
unique_constraint_schema | unique_constraint_name |
match_option | update_rule | delete_rule
--------------------+-------------------+-----------------+---------------------------+--------------------------+------------------------+--------------+-------------+-------------
(0 rows)

Thanks.

Wei

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