Christopher Kings-Lynne <chris.kings-lynne@calorieking.com> writes:
>> Thank you for your help. I found that an implicit index is created for
>> the primary key in the current version. However, it is not done in 7.x
>> version.
> It absolutely is created in all 7.x versions of PostgreSQL.
And every other version too. PRIMARY KEY/UNIQUE syntax was not
supported before this patch:
1997-12-04 18:07 thomas
* src/backend/parser/: analyze.c, gram.y: Add SQL92-compliantsyntax for constraints. Implement PRIMARY KEY and UNIQUE
clausesusingindices.
and in that patch and every subsequent version, unique constraints are
associated with indexes. In fact, we do not even *have* any
implementation method for unique constraints other than the duplicate-
entry-detection code in the btree index AM.
regards, tom lane