help for SQLITE or something else

[mortelpoison]

Hi everyone

i try to find some help for my project. I read many things on this forum but i need help

i am building a application for iphone. in my application you have to create 1 username and password. so i want in the same time create the username in a database

if a another user try to create a username name"Jack" the systeme have to check database to see if this username is already created

so the question is: how i can build this.

thanx a lot