The Data Module

The application wizard would have created a number of files for you, the most important of which is the DataModule class. It contains all of the components required for communicating with the Relativity Server.

For the purposes of this tutorial we are only concerned with a few elements of the class.

Properties

The main property that we use throughout this tutorial is DataAdapter. The data adapter provides all the methods to send and receive data from the server. For instance:

• GetTable retrieves a table with a given name.
• ApplyChanges applies any pending updates to the server.
• InsertRow adds a row to the local copy of the data.
• UpdateRow applies edits to an existing row in the local copy of the data.
• DeleteRow deletes a row from the local copy of the data.

Methods

The DataModule class exposes a number of methods, of which LogOn and LogOff are the most important for this tutorial. A username and password are required to retrieve the data from the server, so before you attempt to retrieve data the user of the app needs to log in. You then pass their username and password into the LogOn method.