Обсуждение: PostgreSQL 7.4.2 new tables [Stupid Query]
PostgreSQL 7.4.2 new tables [Stupid Query]
От
"V i s h a l Kashyap @ [Sai Hertz And Control Systems]"
Дата:
Dear all, Just migrated to PostgreSQL 7.4.2 from 7.3.4 I found that after migration to 7.4.2 some of the tables in my database which were not created by me exists their Namely : 1. information_schema.sql_features 2. information_schema.sql_implementation_info 3. information_schema.sql_languages 4. information_schema.sql_packages 5 information_schema.sql_sizing 6. information_schema.sql_sizing_profiles These tables are viewable only with the psqlODBC connected clients i.e when I connect to database with psqlODBC then only these tables are viewable. My Stupid question is : 1. Is this normal. 2. If this is normal then what are these tables for ? Machine Spec: RH 9.0 PostgreSQL 7.4.2 -- Best Regards, Vishal Kashyap Director / Lead Developer, Sai Hertz And Control Systems Pvt Ltd, http://saihertz.rediffblogs.com Jabber IM: vishalkashyap@jabber.org ICQ : 264360076 Yahoo IM: mailforvishal@yahoo.com ----------------------------------------------- You yourself, as much as anybody in the entire universe, deserve your love and affection. - Buddha --------------- pgsql=# select marital_status from vishals_life; marital_status ------------------ Single not looking 1 Row(s) affected ___ //\\\ ( 0_0 ) ----------------o0o-----o0o---------------------
On Sat, 20 Mar 2004, V i s h a l Kashyap @ [Sai Hertz And Control Systems] wrote: > Dear all, > > Just migrated to PostgreSQL 7.4.2 from 7.3.4 > > I found that after migration to 7.4.2 some of the tables in my > database which were not created by me exists their > Namely : > 1. information_schema.sql_features > 2. information_schema.sql_implementation_info > 3. information_schema.sql_languages > 4. information_schema.sql_packages > 5 information_schema.sql_sizing > 6. information_schema.sql_sizing_profiles > > These tables are viewable only with the psqlODBC connected clients i.e > when I connect to database with > psqlODBC then only these tables are viewable. > My Stupid question is : > 1. Is this normal. > 2. If this is normal then what are these tables for ? It's part of the SQL spec. It's the standard way to get information about the database. For example, from information_schema.sql_features, you can determine things like, we support LEFT OUTER JOIN but not CUBE and ROLLUP. From sql_implementation_info you can see things like the fact that NULLs are treated as greater than non-nulls for sorting purposes. From tables (which isn't mentioned above, but should exists) you can see table names and whether they are base tables or views. They're not generally as powerful as going to the pg_* tables (some details are likely to be left out), but they're standard.