Creating the Client Application

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In most regards, creating a multi-tiered client application is similar to creating a two-tiered client that uses a client dataset to cache updates. The major difference is that a multi-tiered client uses a connection component to establish a conduit to the application server.

To create a multi-tiered client application:

1. Add a new data module to the project.
2. Place a connection component on the data module. The type of connection component you add depends on the communication protocol you want to use. See The Structure of the Client Application for details.
3. Set properties on your connection component to specify the application server with which it should establish a connection. To learn more about setting up the connection component, see Connecting to the Application Server.
4. Set the other connection component properties as needed for your application. For example, you might set the ObjectBroker property to allow the connection component to choose dynamically from several servers. For more information about using the connection components, see Managing Server Connections.
5. Place as many TClientDataSet components as needed on the data module, and set the RemoteServer property for each component to the name of the connection component you placed in Step 2. For a full introduction to client datasets, see Using Client Datasets.
6. Set the ProviderName property for each TClientDataSet component. If your connection component is connected to the application server at design time, you can choose available application server providers from the ProviderName property's drop-down list.
7. Continue in the same way you would create any other database application. There are a few additional features available to clients of multi-tiered applications:
   • Your application may want to make direct calls to the application server. Generating DataSnap Server Method Proxies and Calling Server Interfaces describe how to do this.
   • You may want to use the special features of client datasets that support their interaction with the provider components. These are described in Using a Client Dataset with a Provider.

Topics

• Connecting to the Application Server
  • Specifying a Connection Using dbExpress
  • Specifying a Connection Using DCOM
  • Specifying a Connection Using Sockets
  • Specifying a Connection Using HTTP
  • Specifying a Connection Using SOAP
  • Brokering Connections
• Managing Server Connections
  • Connecting to the Server
  • Dropping or Changing a Server Connection
• Calling Server Interfaces
• Connecting to an Application Server That Uses Multiple Data Modules

See Also

• Connecting to the Application Server
• Creating the Server Application
• Writing Web-based Client Applications
• Using Data Modules