I am working on a small database program. I want to able to check recundancy when a new entry is entered. For example, if Check#1123 already in the database, i need to make sure the same number won't be entered into the same table. I am just a beginer on programing, so please help.

Check this thread

http://forums.asp.net/p/1207418/2122578.aspx#2122578 

Hi, 

Alternatively, you can change the "id" column to be a primary key in database, this will make the id is unique.

To create or change a column to be PRIMARY KEY, you can see this:

http://msdn2.microsoft.com/en-us/library/ms181043.aspx 

   public bool CheckIDNO(string IDNO)
        {
            try
            {
                bool NoExists = false;
                Database db = DAC.GetDataDBConnection();
                DbCommand dbCmd = db.GetStoredProcCommand("CheckNO", IDNO, NoExists);
                db.ExecuteScalar(dbCmd);
                NoExists = (bool)db.GetParameterValue(dbCmd, "Exists");
                if (NoExists)
                    return true;
                else
                    return false;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

source for SP

ALTER PROCEDURE [dbo].[CheckNO]

    @IDNO varchar(25),
    @Exists bit out
AS
BEGIN

    SET NOCOUNT ON;


    IF EXISTS(SELECT IDNO FROM Test WHERE IDNO = @IDNO )
    begin
        set @Exists= 1
    end
    else
        set @Exists= 0
END


I hope this will help you