Re: [SQL] automatic incrementation

Nuchanard Chiannilkulchai ha scritto:

> hello,
>
> I have a table with the field 'id' which i would like to increment at
> each insert automatically.
> The idea is to create a function which determines the max(id) and then a
> rule to insert instead
> the real insertion instruction, with the next id value.
>
> -- table
> create table toto (
>         id      int4       primary key,
>         project char(8) not null,
>         comments text
> );
> insert into toto values (1,'PTest','ndfjSHJG');
> insert into toto values (2,'PTest','ndfjSHJG');
> insert into toto values (3,'PTest','ndfjSHJG');
>
> -- function
> create function nextid(toto) returns int4
>         as ' select max($1.id)+1 as id ; '
>         language 'sql';
>
> **** ERROR:  type id lookup of 12 failed
> This is my first problem
>
> -- rule
> create rule r_id  as on insert to toto
>         do instead
>         insert into toto (id, project, comments) values (nextid(),
> new.project, new.comments);
>
> **** The next problem may be the rule writing !!!
> I would like to have , even some other suggestions to make it works.
> I can't use a sequence table because I've already one in the database.
>
> Thanks,
>     Nuch

What about a SERIAL data type ?

create table toto (       id          SERIAL,       project  char(8) not null,       comments text);

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PostgreSQL 6.5.0 on i586-pc-linux-gnu, compiled by gcc 2.7.2.3
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Jose'