Postgresql allows adding comments to objects such as tables. For example I\'ve added a comment to table \"mytable\" by using this SQL command:
COMMENT ON TAB
You can use pg_catalog.obj_description
function and information_schema.tables
schema view:
SELECT t.table_name, pg_catalog.obj_description(pgc.oid, 'pg_class')
FROM information_schema.tables t
INNER JOIN pg_catalog.pg_class pgc
ON t.table_name = pgc.relname
WHERE t.table_type='BASE TABLE'
AND t.table_schema='public';
FUNCTIONS-INFO-COMMENT-TABLE
INFORMATION_SCHEMA Support in MySQL, PostgreSQL