I have two tables one is members table with columns member id , member first name, member last name. I have another table guest passes with columns guest pass id and member id and issue date . I have a list view that will displays guest passes details (I.e) like member name and issue date and I have two text boxes those are for entering member name and issue date . member name text box is auto complete text box that working fine.... but the problem is when I am entering the name that is not in member table at this time it will accept and displays a blank field in list view in member name column and member id is stored as "0" in guest pass table ...... I don't want to display the member name empty blank and I don t want to store "0" in guest pass table and this is the insert statement sql2 = @"INSERT INTO guestpasses(member_Id,guestPass_IssueDate)"; sql2 += " VALUES("; sql2 += "'" + tbCGuestPassesMemberId.Text + "'"; sql2 += ",'" + tbIssueDate.Text + "'"; guestpassmemberId = memberid is there any validation that need to be done can any one suggestions on this pls... and this is the auto complete text box statement sql = @"SELECT member_Id FROM members WHERE concat(member_Firstname,'',member_Lastname) ='" + tbMemberName.Text+"'"; if (dt != null) { if (dt.Rows.Count > 0) { tbCGuestPassesMemberId.Text = Convert.ToInt32(dt.Rows[0] ["member_Id"]).ToString(); } } can any one help me on this ... is there any type of validation with sql query pls help me .....