Go Up to Migrating to FireDAC

This article guides you through a series of the steps to migrate the BDE application to the FireDAC.

Topics

Introduction

This article provides a tutorial showing how to migrate a simple client-server application using BDE data access components, such as TDatabase, TQuery, TTable, to the FireDAC. It shows the basic principles of replacing the common components, properties and code, preserving the developers working time and avoiding the common migration pitfalls.

Overview

In general, the FireDAC components have a high compatibility level with the BDE data access components. This includes the syntax and semantic of the properties and methods in the FireDAC and BDE. But some parts are different:

• BDE and FireDAC have components with different names  (for example, TQuery component in BDE is TFDQuery in FireDAC.)
• BDE and FireDAC have different alias/connection definition systems. BDE stores aliases in the binary system wide file IDAPI.CFG, while FireDAC stores the connection definitions in the FDConnectionDefs.ini file.
• Some parameters for BDE SQLLink and FireDAC drivers are different.
• BDE and FireDAC can have different data type mapping for the same RDBMS. FireDAC follows a mapping style closely similar to the dbExpress data type mapping. However, FireDAC has powerful capabilities to adjust the data type mapping.
• The base APIs (the BDE API and the Phys interface) are absolutely incompatible. If you have some code which directly uses the BDE API, it has to be recoded.
• BDE and FireDAC have different query syntax and capabilities. FireDAC offers the Local SQL feature.

This is nearly all that needs to be changed at the migration from BDE to FireDAC. After the migration (or in parallel with it), you should consider reviewing your application for:

• Using the extended FireDAC functionality to simplify your application.
• Using the extended FireDAC functionality to extend the functionality of your application.
• Using the FireDAC options to fine-tune your application and speed it up.