Programming the Perl DBI

Architecture of a DBI Application

The API, or Application Programming Interface, defines the call interface and variables to Perl scripts to use. The API is implemented by the Perl DBI extension (see Figure 1.1).

Figure A-1. DBI application architecture

The DBI “dispatches” the method calls to the appropriate driver for actual execution. The DBI is also responsible for the dynamic loading of drivers, error checking and handling, providing default implementations for methods, and many other non-database-specific duties.

Each driver contains implementations of the DBI methods using the private interface functions of the corresponding database engine. Only authors of sophisticated/multi-database applications or generic library functions need to be concerned with drivers.