Rocking ltree on postgresql

Postgresql 9.1 Now ships with a module called ltree. This is a cool postgresql that allows you to model hierarchies in you database and leverages the GIST indexing mechanism built into postgres. Assume you are modeling several organizations:

CREATE TABLE orgs (path ltree);
INSERT INTO orgs VALUES ('Top');
INSERT INTO orgs VALUES ('Top.OrgA');
INSERT INTO orgs VALUES ('Top.OrgA.Division1');
INSERT INTO orgs VALUES ('Top.OrgA.Division1.storeZ');
INSERT INTO orgs VALUES ('Top.OrgA.Division1.storeY');
INSERT INTO orgs VALUES ('Top.OrgA.Division2');
INSERT INTO orgs VALUES ('Top.OrgA.Division2.storeV');
INSERT INTO orgs VALUES ('Top.OrgA.Division2.storeW')
CREATE INDEX path_gist_idx ON test USING gist(path);
CREATE INDEX path_idx ON test USING btree(path); Now you can do some interesting queries such as Give me all the rstores in Division1
select * from orgs where path ~ "Top.OrgA.Division1.*" or give me all the stores (where the path is at least 4 items long)
select * from orgs where path ~ Top.{4}

This is another neat feature that Postgresql gives you but mysql doesn’t

Written on October 25, 2012