Re: create table explicitly mention that unique|primary key constraint will create an

On Mon, 2023-11-27 at 08:00 +0800, jian he wrote:
> Hi. minor doc issue.
> create table s1(a int, constraint s2 PRIMARY key (a));
> create table s2(a int);
> ERROR:  relation "s2" already exists
>
> https://www.postgresql.org/docs/current/sql-createtable.html#SQL-CREATETABLE-PARMS-UNIQUE
> maybe for the following 2 sentence
> "Adding a unique constraint will automatically create a unique btree
> index on the column or group of columns used in the constraint."
> "Adding a PRIMARY KEY constraint will automatically create a unique
> btree index on the column or group of columns used in the constraint."
>
> maybe we can mention that: the unique btree index name will be the
> constraint name.
> also is "a unique" or "an unique"?

It would be "a unique", because "unique" is pronounced "juneek", which
does not start with a vowel.

> I personally thought this part is obscure.

True; I don't find it documented that all objects in pg_class share a
namespace and that constraints are implemented by indexes of the same
name.  But I think that the first part is a property of schemas and had
better be documented there.

What do you think of the attached patch?

Yours,
Laurenz Albe