I have a table in sql that contains a varchar() column called Transaction_Value.

I have a Button in form1 that must update that column with specific word but there are no any updates in table. 

Dim UpdateCmd1 As String = "UPDATE DATAGRID " & _
    "SET Transaction_Type ='" & "Loading" & "' " & _
    "WHERE tank_name ='" & ComboBox1.Text & "' AND material_name = '" & ComboBox2.Text & "'"
If SQL.Update(UpdateCmd1) = 0 Then
    MsgBox("")
    Exit Sub
End If