如何将我的电子邮件文本字段值与iphone中的数据库值进行比较

I have a problem in comparing my textfield email value to the value in sqlite database. If both the values are same then it shows alertbox that "email already exist in database". I have created a function for this purpose named findcontact, I am calling the function from button click. Button click method is working because when I click the button then buttonclick method generate the log which I have written in findContact method.I have a problem in comparing my textfield emai