Contents Index Lesson 3: Write the sample code Write code for navigation and data manipulation

UltraLite for MobileVB User's Guide
  Tutorial: An UltraLite Application for PocketPC
    Lesson 3: Write the sample code

Write code to connect to your database


In this application, you connect to the database using the Form Load event.

Write code to connect to the UltraLite database

  1. Specify the connection parameters.

    1. Add a ULConnectionParms control to your form. The ULConnectionParms control is a database icon on the toolbox.

    2. In the Properties window, specify the following ULConnectionParms properties:

      Property Value
      DatabaseOnDesktop c:\tutorial\mvb\tutCustomer.udb
      DatabaseOnCE \tutorial\mvb\tutCustomer.udb
      SchemaOnDesktop c:\tutorial\mvb\tutCustomer.usm
      SchemaOnCE \tutorial\mvb\tutCustomer.usm
  2. Declare global UltraLite objects.

    These variables will be used through the application. Note that the DatabaseMgr variable is also allocated as a new object.

  3. Add the code to connect to the database in the Form Load event.

    The code below attempts to connect to an existing database. If the database does not exist, it creates a new database from the schema file and establishes a connection.

    Sub Form_Load()
        On Error Resume Next
        Set Connection = _
            DatabaseMgr.OpenConnectionWithParms( _
                ULConnectionParms1)
        If Err.Number = ULSQLCode.ulSQLE_NOERROR Then
            MsgBox "Connected to an existing database"
        ElseIf Err.Number = _
           ULSQLCode.ulSQLE_ULTRALITE_DATABASE_NOT_FOUND _
        Then
            Err.Clear
            Set Connection = _
            DatabaseMgr.CreateDatabaseWithParms( _
               ULConnectionParms1)
            If Err.Number = ULSQLCode.ulSQLE_NOERROR _
            Then
                MsgBox "Connected to a new database"
            Else
                MsgBox Err.Description
            End If
        Else
            MsgBox Err.Description
        End If
    End Sub
  4. Write the code that ends the application and closes the connection when the End button is clicked:

    Sub btnDone_Click()
        Connection.Close
        End
    End Sub
  5. Run the application in the development environment.


Contents Index Lesson 3: Write the sample code Write code for navigation and data manipulation