Question

    Dim conn As OleDbConnection
    Dim cmd As OleDbCommand

    Public Sub openDB()
        conn = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & Application.StartupPath & "\VFMS_DB.mdb;" & "Jet OLEDB:System Database=Security.mdw;User ID=Adster;Password=300624;")
        conn.Open()
    End Sub

    Public Function UpdateUser() As Integer
        Dim retCode As New Integer

        Try
            openDB()
            cmd = conn.CreateCommand()

The update command below keeps giving me this error: “Conversion from string “‘ WHERE [Username] = ‘” to type ‘Double’ is not valid.” and I don’t know why. The aUserName field is a String field and I checked to make sure it’s populated.

            cmd.CommandText = "UPDATE Users SET [First Name] = '" & aName & "', [Last Name] = '" & aSurname & "', [Contact Number] = '" & aContactNum & "', [Password] = '" & aPassword & "', [User Rights] = '" & aUserRights + "' WHERE [Username] = '" + aUserName + "' "

            cmd.ExecuteNonQuery()
            conn.Close()

            'rsAddRecs = rsConn.Execute("UPDATE Users ([First Name], [Last Name], [Contact Number], [User Name], [Password], [User Rights]) VALUES ('" & aName & "','" & aSurname & "','" & aContactNum & "','" & aUserName & "','" & aPassword & "','" & aUserRights & "')")

            retCode = 0
            'rsConn.Close()
            Return retCode

        Catch ex As Exception
            MessageBox.Show(ex.ToString, ex.Message, MessageBoxButtons.OK)
            retCode = 1
            Return retCode
        End Try
    End Function

Answer 1

You have a typo. You’re using + concat characters at the end of the sql string instead of & characters

Wrong

cmd.CommandText = "UPDATE Users SET [First Name] = '" & aName & _ 
                  "', [Last Name] = '" & aSurname & _
                  "', [Contact Number] = '" & aContactNum & _
                  "', [Password] = '" & aPassword & "', [User Rights] = '" & _
                  aUserRights + "' WHERE [Username] = '" + aUserName + "' "
'                             ^                          ^           ^

Right

cmd.CommandText = "UPDATE Users SET [First Name] = '" & aName & _
                  "', [Last Name] = '" & aSurname & _
                  "', [Contact Number] = '" & aContactNum & _
                  "', [Password] = '" & aPassword & "', [User Rights] = '" & _
                  aUserRights & "' WHERE [Username] = '" & aUserName & "' "
'                             ^                          ^           ^