Re: Establishing a primary key - Mailing list pgsql-general

From Scott Marlowe
Subject Re: Establishing a primary key
Date
Msg-id 467C3334.7080108@g2switchworks.com
Whole thread Raw
In response to Establishing a primary key  (Bob Pawley <rjpawley@shaw.ca>)
List pgsql-general
Bob Pawley wrote:
> I have numerous entries in a column of table 1, some of which are
> duplicated.
>
> I need to transfer this information to table 2 so that I have column
> that can be used as a primery key.
>
> Any help is appreciated.

So, I take it you're wanting to have this so that table 1 stays as it
is, and table 2 gets the entries from table 1 made unique, and becomes
the parent of table 1?

If that's the case, you want something like this:

create table2 as select distinct idcolumn from table1;
alter table2 add primary key (idcolumn);
alter table1 add foreign key (idcolumn) references table2(idcolumn);


I think that's about right.

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