Deploying Database Applications

Applications that access databases involve special installation considerations beyond copying the application's executable file onto the host computer. Database access is most often handled by a separate database engine, the files of which cannot be linked into the application's executable file. The data files, when not created beforehand, must be made available to the application. Multi-tier database applications require additional handling on installation, because the files that make up the application are typically located on multiple computers.

Since several different database technologies (ADO, BDE, dbExpress, and InterBase Express) are supported, deployment requirements differ for each. Regardless of which you are using, you need to make sure that the client-side software is installed on the system where you plan to run the database application. ADO, BDE, dbExpress, and InterBase Express also require drivers to interact with the client-side software of the database.

Specific information on how to deploy dbExpress, BDE, and multi-tiered database applications is described in the following topics:

Database applications that use client datasets such as TClientDataSet or dataset providers require you to include midaslib.dcu (for static linking when providing a stand-alone executable); if you are packaging your application (with the executable and any needed DLLs), you need to include Midas.dll.

If deploying database applications that use ADO, you need to be sure that MDAC version 2.1 or later is installed on the system where you plan to run the application. MDAC is automatically installed with software such as Windows 2000 and Internet Explorer version 5 or later. You also need to be sure the drivers for the database server you want to connect to are installed on the client. No other deployment steps are required.

If deploying database applications that use InterBase Express, you need to be sure that the InterBase client is installed on the system where you plan to run the application. InterBase requires gds32.dll and interbase.msg to be located in an accessible directory. No other deployment steps are required. InterBase Express components communicate directly with the InterBase Client API and do not require additional drivers. For more information, refer to the Embedded Installation Guide posted on the CodeGear Web site.

In addition to the technologies described here, you can also use third-party database engines to provide database access. Consult the documentation or vendor for the database engine regarding redistribution rights, installation, and configuration.