Re: Comparing two tables of different database
| От | Isaac Dover |
|---|---|
| Тема | Re: Comparing two tables of different database |
| Дата | |
| Msg-id | [email protected] обсуждение исходный текст |
| Ответ на | Re: Comparing two tables of different database (Lucas Brito <[email protected]>) |
| Список | pgsql-sql |
Thank you, Lucas. I'm from the MS world, still learning these PG things. Though, it appears that the difference is somewhat minor. In my actual implementation, [other database] would be a linked server, which sounds like it would be similar to the PG dblink. Regardless, I've found information schema to be incredibly valuable.
Thanks,
- Isaac
On Sat, May 2, 2009 at 5:25 PM, Lucas Brito <[email protected]> wrote:
2009/5/2 Isaac Dover <[email protected]>i've not tried this in postgres, but using information_schema makes comparing structures of databases trivial. i've been using this query for a while with MSSQL. Maybe this helps to answer the question.- isaacselect ST.Table_Name, ST.Column_Name, DV.Table_Name, DV.Column_Name, *
from [database].information_schema.Columns ST
full outer join [other database].information_schema.Columns DV
on ST.Table_Name = DV.Table_name
and ST.Column_Name = DV.Column_Name
where ST.Column_Name is null or DV.Column_Name is NULL
Isaac, this query will return "ERROR: cross-database references are not implemented".Postgres does not support queries in databases other than current one. Even a simple select * from otherdatabase.information_schema.columns will not work and throw the same error.
However this can be done with dblink function like:select ST.Table_Name, ST.Column_Name, DV.Table_Name, DV.Column_Name, *from information_schema.Columns ST
full outer join dblink('dbname=otherdatabase','select Table_Name, Column_Name from information_schema.Columns') DV(Table_Name text, Column_Name text)on ST.Table_Name = DV.Table_name
and ST.Column_Name = DV.Column_Name
where ST.Column_Name is null or DV.Column_Name is NULL
--
Lucas Brito
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