It's not clear to me how your data is organized or exactly what you're counting. If I understand you correctly, yes, you could use triggers to maintain a table in this manner. However, why can't you simply use a SELECT query using the SUM() or COUNT() aggregate functions? If the queries are slow, do some index tuning. -- Brandon Aiken CS/IT Systems Engineer -----Original Message----- From: pgsql-general-owner@xxxxxxxxxxxxxx [mailto:pgsql-general-owner@xxxxxxxxxxxxxx] On Behalf Of romantercero@xxxxxxxxx Sent: Wednesday, September 06, 2006 2:05 PM To: pgsql-general@xxxxxxxxxxxxxx Subject: [GENERAL] Database design and triggers... Hi everybody. Hope I'm posting in the correct group. My question is part design and part implementation. Since we are creating an inventory system we need to have the clients pull up current inventory. Also, we need to have the past transactions stored for reference and billing. In our previous system in MS Access we accomplished this by adding up all of the transactions stored in two tables and generating a temporary table with the latest inventory count. The problem with this approach is that it is slow because the temporary table has to be created every time a user needs to see a report or work on a form. Even when instead of creating a temporary table we use a query it is still slow. With postgreSQL I found out about triggers and I figure that instead of calculating the current inventory count and storing it in a table every time a client needs it I could have a triggers maintain a table with the current count by incrementing or decreasing the amounts each time a transaction is stored in the transaction tables. My worry is that if for some reason a trigger were to somehow fail to execute correctly there would be an inconsistency between the transactions table and the current inventory count table and it would have to be calculated from scratch taking in to account all of the past transactions in the transactions table. Are trigger a very safe way to use in the way I describe? Or should I try using views or stick with the temporary table solution we already have? My second part of the question is if there is a tutorial for triggers and stored procedures and what is the difference between Procedures and Functions? Thanks Beforehand! ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to majordomo@xxxxxxxxxxxxxx so that your message can get through to the mailing list cleanly
