Thread: Documenting a DB schema
I’m looking for a systematic way to document the schema for the database behind our website (www.redfin.com), so that the developers using this database have a better idea what all the tables and columns mean and what data to expect. Any recommendations?
It would be great if the documentation could be kept as close to the code as possible – that way we stand a chance of keeping it up to date. So, in the same way that Java docs go right there on top of the class or method definitions, it would be great if I could attach my comments to the table definitions. It looks like MySQL has that kind of capability:
create table table_with_comments(a int comment 'this is column a...');
(see http://dev.mysql.com/doc/refman/5.0/en/create-table.html)
However, Postgres doesn’t support the “comment” keyword. Is there an alternative?
Thanks,
--S
Shahaf Abileah | Lead Software Developer
shahaf@redfin.com | tel: 206.859.2869 | fax: 877.733.3469
Redfin Corporation
710 2nd Ave
Suite 600
Seattle, WA 98104
Shahaf Abileah wrote: > > I’m looking for a systematic way to document the schema for the > database behind our website (www.redfin.com <http://www.redfin.com/>), > so that the developers using this database have a better idea what all > the tables and columns mean and what data to expect. Any recommendations? > > It would be great if the documentation could be kept as close to the > code as possible – that way we stand a chance of keeping it up to > date. So, in the same way that Java docs go right there on top of the > class or method definitions, it would be great if I could attach my > comments to the table definitions. It looks like MySQL has that kind > of capability: > > create table table_with_comments(a int comment 'this is column a...'); > > (see http://dev.mysql.com/doc/refman/5.0/en/create-table.html) > > However, Postgres doesn’t support the “comment” keyword. Is there an > alternative? > > Thanks, > > --S > > *Shahaf Abileah *|* Lead Software Developer * > > shahaf@redfin.com | tel: 206.859.2869 | fax: 877.733.3469 > > Redfin Corporation > 710 2nd Ave > Suite 600 > Seattle, WA 98104 > Its probably best to try one list and see if you get a response rather than sending the same message to 3 lists. Comments are supported CREATE TABLE follow_me_destination ( mailbox_number character varying(10), -- Follow me users mailbox number. destination_number character varying(32), -- Follow me phone number. dest_id serial NOT NULL ) WITHOUT OIDS; ALTER TABLE follow_me_destination OWNER TO postgres; COMMENT ON TABLE follow_me_destination IS 'Stores follow me numbers for system users.'; COMMENT ON COLUMN follow_me_destination.mailbox_number IS 'Follow me users mailbox number.'; COMMENT ON COLUMN follow_me_destination.destination_number IS 'Follow me phone number.';
On Tuesday 04 March 2008, "Shahaf Abileah" <shahaf@redfin.com> wrote: > > However, Postgres doesn't support the "comment" keyword. Is there an > alternative? comment on table table_name is 'comment'; comment on column table.column_name is 'comment'; -- Alan
Shahaf Abileah wrote:
> It would be great if the documentation could be kept as close to the
> code as possible – that way we stand a chance of keeping it up to date.
> So, in the same way that Java docs go right there on top of the class or
> method definitions, it would be great if I could attach my comments to
> the table definitions. It looks like MySQL has that kind of capability:
Please do not cross-post. One list is enough.
PostgreSQL has that functionality, too.
cww=# CREATE TABLE foo (a INTEGER, b INTEGER);
CREATE TABLE
cww=# COMMENT ON TABLE foo IS 'my comment';
COMMENT
cww=# \d+
List of relations
Schema | Name | Type | Owner | Description
--------+------+-------+-------+-------------
public | foo | table | cww | my comment
(1 row)
COMMENT is well-documented.
http://www.postgresql.org/docs/8.3/static/sql-comment.html
Colin
Check http://www.postgresql.org/docs/8.3/interactive/sql-comment.html Cheers! Shahaf Abileah wrote: > I’m looking for a systematic way to document the schema for the database > behind our website (www.redfin.com <http://www.redfin.com/>), so that > the developers using this database have a better idea what all the > tables and columns mean and what data to expect. Any recommendations? > > > > It would be great if the documentation could be kept as close to the > code as possible – that way we stand a chance of keeping it up to date. > So, in the same way that Java docs go right there on top of the class or > method definitions, it would be great if I could attach my comments to > the table definitions. It looks like MySQL has that kind of capability: > > > > create table table_with_comments(a int comment 'this is > column a...'); > > > > (see http://dev.mysql.com/doc/refman/5.0/en/create-table.html) > > > > However, Postgres doesn’t support the “comment” keyword. Is there an > alternative? > > > > Thanks, > > > > --S > > > > *Shahaf Abileah *|* Lead Software Developer * > > shahaf@redfin.com | tel: 206.859.2869 | fax: 877.733.3469 > > Redfin Corporation > 710 2nd Ave > Suite 600 > Seattle, WA 98104 > > >
You mean like:I’m looking for a systematic way to document the schema for the database behind our website (www.redfin.com), so that the developers using this database have a better idea what all the tables and columns mean and what data to expect. Any recommendations?
It would be great if the documentation could be kept as close to the code as possible – that way we stand a chance of keeping it up to date. So, in the same way that Java docs go right there on top of the class or method definitions, it would be great if I could attach my comments to the table definitions. It looks like MySQL has that kind of capability:
create table table_with_comments(a int comment 'this is column a...');
(see http://dev.mysql.com/doc/refman/5.0/en/create-table.html)
However, Postgres doesn’t support the “comment” keyword. Is there an alternative?
COMMENT ON mytable IS 'This is my table. Mine, mine, mine';
You can also comment columns, databases, functions, schemas, domains, etc.
Cheers,
Steve
On Tue, Mar 04, 2008 at 12:02:27PM -0800, Shahaf Abileah wrote: > I'm looking for a systematic way to document the schema for the database > behind our website (www.redfin.com <http://www.redfin.com/> ), so that > the developers using this database have a better idea what all the > tables and columns mean and what data to expect. Any recommendations? You can and should be using COMMENT ON for the important database objects. http://www.postgresql.org/docs/current/static/sql-comment.html > It would be great if the documentation could be kept as close to the > code as possible - that way we stand a chance of keeping it up to > date. If your schema is changing substantively (i.e. anything other than adding/dropping table partitions) with any frequency, that's a sign of a broken design process which you need to fix. > So, in the same way that Java docs go right there on top of the class or > method definitions, it would be great if I could attach my comments to > the table definitions. It looks like MySQL has that kind of capability: See above re: COMMENT ON :) > create table table_with_comments(a int comment 'this is > column a...'); > > (see http://dev.mysql.com/doc/refman/5.0/en/create-table.html) > > However, Postgres doesn't support the "comment" keyword. Actually, it does :) > Is there an alternative? Cheers, David. -- David Fetter <david@fetter.org> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fetter@gmail.com Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate