Re: [SQL] Question about SQL FUnction

On Wed, 17 Feb 1999, Martin [iso-8859-1] M�derndorfer wrote:

> hi,

Hi Martin

>
> i have some tables:
>
> create table person (nr int4, name varchar(50));
> create table book(nr int4, title varchar(50), persnr int4);
>
> (persnr is the foreign key -> person.nr)
>
> now i have some
> CREATE FUNCTION get_new_nr(**TABLE**,**FIELDS**) RETURNS int4;
>    AS 'SELECT MAX($2) FROM $1 +1;'
>    LANGUAGE 'sql';
>
> but **table** and **fields** needs some datatype. this function should
> return the max of a set of all numbers in person (+1) and return this.

Are you trying to get the MAX($2) in order to calculate the next value for
the primaryy key ????

If that's true, i would recommend you to use sequences

>
> is it possible (and how ;-) to write such a very _flexible_ function??
>
> MArtin
>

Functions written in sql are not very flexible... you just can't use the
arguments very well. It is better to write C functions with libpq.

Adios amigo.


David Martinez Cuevas
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