On Wed, Nov 4, 2009 at 1:14 PM, Leif Biberg Kristensen <l...@solumslekt.org> wrote: > On Wednesday 4. November 2009 21.03.26 Scott Marlowe wrote: >> On Wed, Nov 4, 2009 at 11:53 AM, Leif Biberg Kristensen >> > This looks strange to me, but it works: >> > >> > pgslekt=> CREATE TABLE participant_notes ( >> > pgslekt(> person_fk INTEGER NOT NULL, >> > pgslekt(> event_fk INTEGER NOT NULL, >> > pgslekt(> part_note TEXT, >> > pgslekt(> PRIMARY KEY (person_fk, event_fk), >> > pgslekt(> FOREIGN KEY (person_fk, event_fk) REFERENCES participants >> > (person_fk, event_fk) >> > pgslekt(> ); >> > NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index >> > "participant_notes_pkey" for table "participant_notes" >> > CREATE TABLE >> >> Note that this will limit you to one record in your participant notes >> for each record in the participants table. > > That's exactly what I want :) > > For all practical purposes, the design is equivalent to adding a TEXT column > to the participants table. But as I expect a very small number of notes > compared to the number of rows in the participants table, I prefer to create a > small extra table rather than having a large number of null values in the > participants table. Performance-wise, it probably doesn't matter much. It's > more a matter of taste.
Exactly. Note that null values i pgsql take up VERY little space, so performance-wise one table is likely faster, but it's not gonna break the bank to have two. -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
