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Creating the Application Server
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You create an application server very much as you create most database applications. The major difference is that the application server uses a remote data module.

To create an application server

1. Start a new project:
   - If you are using SOAP as a transport protocol, this should be a new Web Service application. Choose FileNewOther, and on the WebServices page of the new items dialog, choose SOAP Server application. Select the type of Web Server you want to use, and when prompted whether you want to define a new interface for the SOAP module, say no.
   - For any other transport protocol, you need only choose FileNewApplication. Save the new project.
2. Add a new remote data module to the project. From the main menu, choose FileNewOther, and on the ActiveX, Delphi Files, or WebServices page of the new items dialog, select
   - Remote Data Module if you are creating a COM Automation server that clients access using DCOM, HTTP, or sockets.
   - Transactional Data Module if you are creating a remote data module that runs under COM+ (or MTS). Connections can be formed using DCOM, HTTP, or sockets. However, only DCOM supports the security services.
   - SOAP Server Data Module if you are creating a SOAP server in a Web Service application. For more detailed information about setting up a remote data module, see Setting up the remote data module.
     Note: Remote data modules are more than simple data modules. The SOAP data module implements an invokable interface in a Web Service application. Other data modules are COM Automation objects.
3. Place the appropriate dataset components on the data module and set them up to access the database server.
4. Place a TDataSetProvider component on the data module for each dataset you want to expose to clients. This provider is required for brokering client requests and packaging data. Set the DataSet property for each provider to the name of the dataset to access. You can set additional properties for the provider. See Using provider components for more detailed information about setting up a provider. If you are working with data from XML documents, you can use a TXMLTransformProvider component instead of a dataset and TDataSetProvider component. When using TXMLTransformProvider, set the XMLDataFile property to specify the XML document from which data is provided and to which updates are applied.
5. Write application server code to implement events, shared business rules, shared data validation, and shared security. When writing this code, you may want to
   - Extend the application server's interface to provide additional ways for the client application to call the server.
   - Provide transaction support beyond the transactions automatically created when applying updates.
   - Create master/detail relationships between the datasets in your application server.
   - Ensure your application server is stateless.
   - Divide your application server into multiple remote data modules.
6. Save, compile, and register or install the application server.
7. If your server application does not use DCOM or SOAP, you must install the runtime software that receives client messages, instantiates the remote data module, and marshals interface calls.
   - For TCP/IP sockets this is a socket dispatcher application, Scktsrvr.exe.
   - For HTTP connections this is httpsrvr.dll, an ISAPI/NSAPI DLL that must be installed with your Web server.

See Also

Creating the Client Application

Registering the Application Server

Writing Web-based Client Applications

The Structure of the Application Server

Copyright(C) 2009 Embarcadero Technologies, Inc. All Rights Reserved.
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