How to Catch Duplicate Entry - Primary Key
This tutorial will guide you on how to determine if the primary key entered is already exist in the table. I created this tutorial in the hope to help newbie’s programmer solve this common problem.
Instead of displaying the default message cast by Visual Basic a message “Employee ID already exist. Please enter another Employee ID.” will appear.
For those who would like to see the source code without downloading the attachment here it is:
- Private Sub CmdAdd_Click()
- On Error GoTo err_CmdAdd_Click
- Dim cnData As New Connection
- Dim rst As New Recordset
- cnData.Open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & App.Path & "\Data.mdb;Persist Security Info=False"
- With rst
- .CursorLocation = adUseClient
- .Open "SELECT * FROM Employees", cnData, adOpenStatic, adLockOptimistic
- !EmployeeID = txtEmployeeID.Text
- !Firstname = txtFirstname.Text
- !Lastname = txtLastname.Text
- MsgBox "Record added successfully...", vbInformation
- End With
- Exit Sub
- If Err = -2147467259 Then
- MsgBox "Employee ID already exist. Please enter another Employee ID.", vbCritical
- MsgBox Err.Description, vbInformation
- End If
- End Sub
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