I would say that pg_catalog is the more complete one whereas the information_schema the more generic, standards-conformant place. I would stick with the information_schema unless that becomes inadequate. A case in point may be sequences. Apart from information_schema.columns.column_default I haven't seen them represented anywhere there (please someone correct me if I am wrong). You can get more information about sequences from pg_catalog.pg_class (look for pg_class.relkind='S') and various views that sit on top of that (e.g. pg_statio_all_sequences).
George > I'm writing PL/pgSQL routines that generate triggers, functions, > and rules based on design characteristics of tables, columns, and > other database objects. These routines need to be able to look up > the definitions of these objects. I see that there are two places > available to look up this info: the Information Schema and in the > PG Catalog. > > Which source is preferable? Or if that answer isn't absolute, > what are the reasons or conditions for preferring one over the > other? > > Also, a specific question: Does the Information Schema offer any > way to list the sequences that exist and their attributes? I > can't seem to find any. > ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
