Crating program for access parallel

Hi all I am creating a program PHP that will be access int the web for many persons, this aplication will be permit to insert registry on a data base Postgresql, When a person this inserting a registry I need to block that table so that another user cannot to access the data base. Exists some form in php to do this? I want to Know how can I save information on a Data Bse that will be access for many persons at the same time. Thanks in advanced for yuor advices !!! Regards, _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp