how yo trap this second column?

i want to trap, example i have foreign key or itemno 1 with rose if i attemp to add rose under itemno 1 it will trap me

Code:

---

If TxtItemNu.Text = "" Then
          MsgBox "No Item Number entered.", vbOKOnly + vbCritical, "ERROR: Empty field/s. "
'          TxtItemNu.SetFocus
          Exit Sub
      End If
     
If TxtFlowerID.Text = "" Then
          MsgBox "No Flower ID entered.", vbOKOnly + vbCritical, "ERROR: Empty field/s. "
'          TxtFlowerID.SetFocus
          Exit Sub
      End If
     
If CboQuantity.Text = "" Then
          MsgBox "No Quantity entered.", vbOKOnly + vbCritical, "ERROR: Empty field/s. "
          CboQuantity.SetFocus
          Exit Sub
      End If
     
    On Error GoTo errSave
        Dim sqlstr As String
            sqlstr = "Insert Into STRUCTURE(STR_ITEMNO,STR_FLOWER,STR_QTY) values(" & TxtItemNu.Text & "," & TxtFlowerID.Text & "," & CboQuantity.Text & ")"
         
                If CStr(TxtItemNu.Text) = CStr(TxtFlowerID.Text) Then
                MsgBox ("The Item Number Can't be The Same with Flower ID")
                    Exit Sub
                End If
           
            Conn.BeginTrans
            Conn.Execute sqlstr
            Conn.CommitTrans
           
            MsgBox "STRUCTURE successfully saved!"
           
            CmdSave.Enabled = False
            CmdDelete.Enabled = False
           
            ClearText
            Unload Me
            Form1.Show
       
ExitErr:
    Exit Sub
errSave:
        Conn.RollbackTrans
        MsgBox "Error" & Err.Description, vbCritical
Resume ExitErr
                 
End Sub

---

how can i do that?
to avoid redundancy itemname in every itemno...

I cannot help you with VB6 but in sql server side you can do some things.
You can set a trigger to check for you if the value is the same and stop execution.
You can create an unique index that can be done easily with management studio.

If you wish to do check for foreign key before inserts, you would be better off with a stored procedure.
A simple example is here.

Ok a little spam here but abhijit what is this beside you on your avatar? :bigyello:

Create relevant database constraints