How to throw a error in asp.net if already exist

Question

if i enter a email id in registration form . then again i registration with another name but use the same email id . i need to throw the error email id already exists in asp.net using c#

Krishna Garad · Answer

you can create table with unique key on email like Create Table TblUser ( Name Varchar(100) Email Varchar(50)Unique etc.... ) When you are inserting values in the table first you need to check the email exists or not for the easiest you can use stored procedure like Create Procedure Sp_RegisterUser ( @name Varchar(200) @email Varchar(50) @message Varchar(200)out ) As Begin if not exists(Select Email From TblUser Where Email=@email) Begin Insert Statement Set @message='User Registered' End Else Begin Set @message='Email Already Exists' End End Hope this may helps you

Keyur Narkhi · Answer

Hi For that you need to check in the database that email is exists or not.If email is exists then you can simply display a error message in the label that email is exists. Or you can create the unique key on Emailwhich gives you an error on save for duplication and handle it in the catch block and display that error. Hope this helps. thanks

Keyur Narkhi · Answer

Hi Please follow this url http://blog.sqlauthority.com/2007/02/05/sql-server-primary-key-constraints-and-unique-key-constraints/ http://www.w3schools.com/sql/sql_unique.asp Hope this helps thanks

selvi subramanian · Answer

how to create unique key in sqlserver