dbExpress is Embarcadero

Embarcadero Technologies

Embarcadero Technologies is an American computer software company that develops, manufactures, licenses, and supports a wide range of products and services related to software through its various dynamic product divisions...

's data driver architecture that replaced the older Borland Database Engine

Borland Database Engine

Borland Database Engine is the Windows-based core database engine and connectivity software behind Borland Delphi, C++Builder, IntraBuilder, Paradox for Windows, and Visual dBASE for Windows.-History:...

. First released with Borland Delphi 6 and C++Builder 6, it has gone through several iterations itself, the latest being shipped with Embarcadero Delphi XE2. It provides unidirectional database access, that means you can traverse data obtained from a database table only in the forward direction. You cannot go back, unless you add other layers. This makes dbExpress a very fast access technology, compared to many others.

Embarcadero supplies drivers for many databases, including Oracle

Oracle database

The Oracle Database is an object-relational database management system produced and marketed by Oracle Corporation....

, Firebird

Firebird (database server)

Firebird is an open source SQL relational database management system that runs on Linux, Windows, and a variety of Unix. The database forked from Borland's open source edition of InterBase in 2000, but since Firebird 1.5 the code has been largely rewritten ....

, InterBase

InterBase

InterBase is a relational database management system currently developed and marketed by Embarcadero Technologies. InterBase is distinguished from other DBMSs by its small footprint, close to zero administration requirements, and multi-generational architecture...

, DB2

IBM DB2

The IBM DB2 Enterprise Server Edition is a relational model database server developed by IBM. It primarily runs on Unix , Linux, IBM i , z/OS and Windows servers. DB2 also powers the different IBM InfoSphere Warehouse editions...

, Informix, SQL Server

Microsoft SQL Server

Microsoft SQL Server is a relational database server, developed by Microsoft: It is a software product whose primary function is to store and retrieve data as requested by other software applications, be it those on the same computer or those running on another computer across a network...

, MySQL

MySQL

MySQL officially, but also commonly "My Sequel") is a relational database management system that runs as a server providing multi-user access to a number of databases. It is named after developer Michael Widenius' daughter, My...

, Firebird

Firebird

-Music:* The Firebird, ballet for which Igor Stravinsky composed the music* Firebird , late 1990s/2000s blues-based power trio* The Firebirds, a rock and roll band from Bristol...

 and ODBC. Additional drivers are available from third parties. Starting with Delphi 2007 (dbExpress 4 generation) a tracing driver is included as well which allows for logging all statements sent to the database.

Prior to version 4 of dbExpress the drivers used the Microsoft COM technology and most drivers were not unicode

Unicode

Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...

enabled. Nowadays the drivers are written in Delphi itself and source code for most parts is available. Most drivers today are unicode enabled since Delphi itself switched to unicode with version 2009.