DataFlex DB2 Driver

The DataFlex DB2 Driver is used to access DB2 Universal Database databases from DataFlex programs. DB2 is a relational database management system (RDBMS) from IBM. It runs on a variety of platforms offering client server functionality to database applications.

Many existing DataFlex applications, without change, will be able to use the DB2 Database Server for data storage. Others require changes in order to perform well with the DB2 Universal Database System.

DB2 Universal Database

DB2 is a multi user Relational Database Management System (RDBMS) that runs on a variety of operating systems. SQL is used to access data in a DB2 Universal Database. Client workstations communicate with a DB2 Universal Database server across a network

A relational database can be viewed as a set of tables that can be manipulated in accordance with the relational model of data. It contains a set of objects used to store, manage, and access data. SQL is a standardized language for defining and manipulating data in a relational database.

In a database Client/Server environment, the following two processes communicate: the database client and the database server. The Client/Server architecture allows all of the client’s data requisitions to be executed by one or several servers. Thus, data manipulation is separated, carried out by the Client, and data management/recording, carried out by the server, offering greater integrity, and speed in the processing of information.

The DataFlex DB2 Driver uses the DB2 Call Level Interface (CLI) to connect DataFlex programs to DB2. CLI is an Application Programming Interface (API) in which functions are provided to applications to process dynamic SQL statements. CLI enables DataFlex to connect to DB2 databases, issue SQL statements and get data and status information without being compiled against a specific database.

DataFlex and DB2

The Data Access database API expects database drivers to support a certain set of attributes for a table. These attributes may or may not be available in the supported backend. If such an attribute is not available in the backend it needs to be stored somewhere outside of the backend database. The API uses intermediate files to store such information. The contents of an intermediate file are partly API defined and partly driver specific.

The DB2 driver will use the DB2 backend for its attributes whenever possible. The goal is to keep the intermediate file as small as possible. Some information can only be stored in the intermediate file because DB2 does not support an attribute that is essential to DataFlex. The DB2 driver expects an intermediate file to be present for every table that is accessed through it.

A design goal of the DB2 driver was that a DataFlex program should be able to switch the underlying database to DB2 without the need to adjust that program.

See Also

DataFlex SQL Drivers