SQL Bible [Electronic resources] نسخه متنی

Summary

The database connectivity standard is an
established fact, with its most successful commercial implementation being
Microsoft ODBC 3.0 interface. There are dozens of ODBC drivers for all types of
data sources ranging from RDBMS to flat text files, available on virtually
every platform — Microsoft Windows, various Unix flavors, and Mac OS, to name
just a few.

The CLI/SQL standard establishes a set of
functions that are used by applications in a uniform fashion to access data
sources and perform data-related tasks.

All communication between the application
and the data source is conducted through ODBC drivers, which are loaded and
unloaded on demand by the Driver Manager. The ODBC (CLI/SQL) drivers work in a
way similar to a live interpreter — it speaks a common language (ODBC functions
set) to the application (through the Driver Manager) and also speaks native
RDBMS dialect.

There are a number of emerging
technologies for defining the application-RDBMS interaction. The most popular
are Java Database Connectivity (JDBC), Microsoft Active Data Objects (ADO), and
ADO.NET (an object-oriented interface to the OLEDB API or ODBC API), in
addition to the new "native" .NET providers.

Every RDBMS vendor has its own version of
Call Level Interface: Oracle's Oracle Call Interface (OCI), IBM DB2 UDB Call
Level Interface (CLI), and Microsoft DBLIB. Some of these are becoming
increasingly obsolete, although they provide the maximum performance in terms
of the raw speed.