Re: [GENERAL] About index - "a query or data manipulation command
On Tue, 2005-04-26 at 13:58 -0400, Ying Lu wrote: > select * from A left join B using (id) where A.type='apple' and > A.isExport=true; > > "id" is the primary key for both table A & B. If index (type, isExport) > has been created for table A. In the above query, will this index works? simplest is just to do an explain. explain select * from A left join B using (id) where A.type='apple' and A.isExport=true; gnari ---(end of broadcast)--- TIP 7: don't forget to increase your free space map settings
Re: [GENERAL] SQLException "Connection is closed. Operation is not
On Mon, 2005-04-25 at 03:38 +0530, Rajiv Verma wrote: > I'm accessing postgres database through tomcat 4.3.1. > I'm able to execute the select and update query through my application > but Insert query is giving following SQLException : > Connection is closed. Operation is not permitted. looks like your application is closing the database connection before the insert. are you doing the insert within the same tomcat request as the selects ? con you reproduce this using the simplest possible test case. i.e: have your doPost() only a) open db connection b) perform select c) perform insert d) close db connection e) return ok page gnari ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
Re: [GENERAL] Primary Key and Indices
On Sun, 2005-04-24 at 09:49 -0700, Rich Shepard wrote: >I'm converting mysql tables to postgres. One of the tables has this: > >PRIMARY KEY (org_id, contact_id), >KEY contact (contact_id, org_id) > >Is there really a difference in the two indices if the sequence of fields > is reversed? yes. for example, only the first one can be used for ORDER BY org_id gnari ---(end of broadcast)--- TIP 8: explain analyze is your friend
