Question

I’m trying to do a very simple INSERT using VB.NET. For some reason I’m getting a SqlException on every insert though. The data is inserted, but still get the following:

Violation of PRIMARY KEY constraint ‘PK_User’. Cannot insert duplicate key in object ‘dbo.Employee’. The statement has been terminated

When I check in SQL Management Studio, the data is succesfully inserted.

Here is the code where the problem is happening

Try     conn.Open()     Dim insertSQL As String = 'insert into Employee(uName, firstName, lastName,         On_Switch, On_Phone) ' + 'values('' & uName & '', '' & firstName & '', '' _         & lastName & '', '' & onSwitch & '', '' & onPhone & '')'         Dim AddCom As SqlCommand = New SqlCommand(insertSQL, conn)          If (AddCom.ExecuteNonQuery() = 1) Then              lblError.Text = 'User Added.'             ' string urlBack = '../ViewAsset.aspx?DeptID=' + DeptID;             ' Response.Redirect(urlBack);         End If          conn.Close()      Catch ex As SqlException         Dim ExMsg As String = ex.Message.ToString()         lblError.Text = ExMsg 

I went back and tested the same code in C# and there is no Exception thrown. It seems to be something small I’m doing in VB, but I’m lost as to what it is.

Answer 1

Two theories. Either your code is being executed twice, or there’s a trigger on the Employee table that’s attempting an insert following the successful insert. (Edit: @Mitchel Sellers is exactly right, if the same code works in c# it’s absolutely not a trigger issue.)

My hunch is that your code is being executed twice. Try running with the debugger attached and a breakpoint set on the ExecuteNonQuery – I think you’ll find that some other method calls this method multiple times.

@Mitchel Sellers – GOOD CATCH ON THE SQL INJECTION BUG! Parameters, please!