The vocabulary that often appears in Delphi is ADO, BDE, DBEXPRESS, and more, then there is an excessive difference, how many of the database engines in Delphi? Maybe it should be grasped as a whole.
Delphi provides four design standards for four data programs, which are Borland Database Engine (BDE), ActiveX Data Object (ADO), DBEXPRESS, InterBase Express.
(1) Delphi's BDE is a 32-bit database engine in a window environment. It also provides a set of API functions that can be called by dynamic linked files, or you can also use Delphi to use the BDE. Components to use these API.BDEs to provide SQL Links to link six background database Sybase, Interbase, Oracle, MS-SQL, INFORMIX, DB2, if the background database is not the six mentioned above, can additionally purchase ODBC Drivers to link other types Database, in the Local (local desktop database), support paradox (*. Db), dbase (*. Dbf), Microsoft FoxPro, Microsoft Access, etc., but also provides a clicking version of Interbase, let you in stand-alone In the environment, you can simulate the development of the main from the database. If you use the programs developed with Delphi, you must install BDE on the user's computer, and Inprise does not charge any fees.
(2) Microsoft implemented the OLE DB of COM, used to replace the ODBC role, as its access to the intermediary software, and ADO is the top of OLE DB, which is used to let Windows applications call (Inteface), in fact, ADO is just a small part of MDAC, MDAC's full name Microsoft Data Access Components, MDAC runs all Microsoft database access technology, such as: ADO, OLE DB, ODBC, RDS (Remote Data Service), So after you install MDAC, the various database access technologies mentioned above will be installed. Software developed with ADO, you must install the corresponding version of MDAC on the user's computer, you can download free (
http://www.microsoft.com)
(3) Due to poor access efficiency in BDE, and the SQL Link driver is difficult to write, the platform transplant is difficult, so Delphi body weight Another database access intermediate standard DBEXPRESS, Borland's programming of DBEXPRESS for various databases (DBEXPRESS Native Driver) and encapsulates a set of dbexress components. DBExpress has the advantage of easy data access efficiency and platform transfer, because BDE yourself has a set of database engines, so it maintains the Cursor queried by the database, so the access efficiency is more Poor, and DBEXPRESS Dataset from Database Fetch (extracted) is Undirectional Cursor, so the access efficiency is much better than BDE. And the Native Driver standard provided by DBEXPRESS is easy to write, high portability, currently there is already a Linux version DBEXPRESS.
(4) Delphi also provides a set of native components Interbase Express let you be directly, fast Wang Wen Interbase database, which encapsulates the API provided by InterBase, and its access efficiency is even higher than BDE and DBEXPRESS, the only lack The trap is its ACC in Interbase Server, does not apply to access to other database servers. In Delphi CD, a relational database system contains a relational database system: Interbase, this interbase must be installed on the operating system of Windows NT technology, Borland Company Free of this database system is used to let you only need to buy Delphi's Enterprise version to pirate a complete master-slave structure system. After you develop a complete set of applications, you can buy other types of other classes. The background database system. This can be seen that this Interbase Server is used by the developer, not for the user, so if you distribute this Interbase to multiple users, then you will violate the copyright law, if you use Interbase When the owner runs from the background database, you can purchase the original version to Borland.
Note: Delphi's own database maintenance tool Database Desktop cannot modify the table structure of the SQL database (such as MS-SQL, Oracle, Sybase), which can only modify the table structure of the Local database (such as DBASE, PARADOX, FOXPRO, Access).
