help with table constraint / check - Mailing list pgsql-sql

From cliff@cliffmeyers.com
Subject help with table constraint / check
Date
Msg-id 20030315073820.3084.h016.c001.wm@mail.cliffmeyers.com.criticalpath.net
Whole thread Raw
Responses Re: help with table constraint / check  (Bruno Wolff III <bruno@wolff.to>)
List pgsql-sql
hello,
This is my first post to the list, so if I make any mistakes, bear with me.  I
have a table that has the follow attributes:


fs_id integer not null default  nextval('public.extranet_filesystem_fs_id_seq'::text)
parent_id integer not null default 0
fs_name character varying(255) not null
fs_type character varying(4) not null default 'file'
Indexes extranet_filesystem_pkey primary key btree (fs_id) extranet_filesystem_u1 unique btree (parent_id, fs_name)
Check constraints:  "extranet_filesystem_fs_type"  ((fs_type = 'file'::character varying) OR (fs_type =
'dir'::charactervarying))
 
Foreign Key constraints:  $1 FOREIGN KEY (parent_id) REFERENCES extranet_filesystem(fs_id) ON UPDATE
CASCADE ON DELETE CASCADE


What I want to do is set up a constraint / check so that when a record is added,
it takes the parent_id being passed in the INSERT statement, looks at the record
whose fs_id equals the parent_id, and makes sure that the fs_type for that record
is 'dir' and not 'file'.

Can I do this with standard constraints or do I need to use some PL/pgSQL
features? Anyone have a few hints? Thanks!


-Cliff


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