[GENERAL] default value based on select
Hi, Is it possible to have a table's column default value set to some form of select? e.g. picking another table's value for a given SELECT ... WHERE ... Already thankful for any insight, -- Pedro Doria Meunier Ips. da Olaria, Edf. Jardins do Garajau, 4, r/c Y 9125-162 Caniço Madeira - Portugal -- Skype : pdoriam Mobile: +351961720188 signature.asc Description: This is a digitally signed message part.
Re: [GENERAL] default value based on select
On Sat, 5 Apr 2008, Pedro Doria Meunier [EMAIL PROTECTED] writes: Is it possible to have a table's column default value set to some form of select? AFAIK, you cannot provide sub-selects in the default values of a field. E.g. CREATE TABLE foo (bar int DEFAULTS (SELECT ...), ...); For this, I know two solutions: 1. You can create an SQL function that issues the related sub-select and call this function as the default value of the column. 2. Create a BEFORE INSERT/UPDATE trigger that issues the related sub-select if related column appears to be un-specified. Regards. -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
Re: [GENERAL] default value based on select
Hello On 05/04/2008, Pedro Doria Meunier [EMAIL PROTECTED] wrote: Hi, Is it possible to have a table's column default value set to some form of select? directly no, but you can use function postgres=# create table a(a integer); CREATE TABLE postgres=# create function mx() returns int as $$select max(a) from a$$ language sql volatile; CREATE FUNCTION postgres=# create table b(x integer default mx()); CREATE TABLE Regards Pavel Stehule e.g. picking another table's value for a given SELECT ... WHERE ... Already thankful for any insight, -- Pedro Doria Meunier Ips. da Olaria, Edf. Jardins do Garajau, 4, r/c Y 9125-162 Caniço Madeira - Portugal -- Skype : pdoriam Mobile: +351961720188 -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
Re: [GENERAL] default value based on select
Pavel and Volkan Thank you for your kind (and prompt) replies. Let me try to better explain my needs: The record being created has a column with an Id that has to be passed as an argument to the function that, in turn, fills the other column in the same record. Does this even make sense? :) Kind regards, -- Pedro Doria Meunier Ips. da Olaria, Edf. Jardins do Garajau, 4, r/c Y 9125-162 Caniço Madeira - Portugal -- Skype : pdoriam Mobile: +351961720188 signature.asc Description: This is a digitally signed message part.
Re: [GENERAL] default value based on select
On Sat, 5 Apr 2008, Pedro Doria Meunier [EMAIL PROTECTED] writes: The record being created has a column with an Id that has to be passed as an argument to the function that, in turn, fills the other column in the same record. Doesn't BEFORE INSERT/UPDATE trigger solve this problem? (If not, I wonder what is missing.) Regards. -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
