11.1 What Is PL/SQL?
PL/SQL
is
a procedural programming language from Oracle Corporation that
combines the following elements:
Logical constructs such as IF-THEN-ELSE and WHILE SQL DML statements, built-in functions, and operators Transaction control statements such as COMMIT and ROLLBACK Cursor control statements Object and collection manipulation statements
Despite its humble origins as a scripting language in Version 6.0,
PL/SQL became an integral part of the Oracle server with release 7.0,
which correlates to release 2.0 of PL/SQL. Because release 7.0
included the ability to compile and store PL/SQL programs within the
server, Oracle began using the language to provide server
functionality and to assist in database installation and
configuration. When release 2.1 of PL/SQL was included with the 7.1
release of the server, Oracle added a new feature of particular use
to SQL programmers: the ability to call PL/SQL stored functions from
SQL statements (more on this later).
Along with the array of new features made available with each release
of PL/SQL, Oracle began supplying prefabricated sets of PL/SQL
functionality to allow programmers to tackle more sophisticated
programming tasks and to help integrate with various Oracle product
offerings. These collections of stored procedures and functions,
known as Oracle Supplied
Packages, allow you to (among other things):
Interface with and administer Oracle's Advanced
Queueing option
Schedule database tasks for periodic execution Manipulate Oracle large objects (LOBs) Read from and write to external files Interface with Oracle's Advanced Replication features Issue dynamic SQL statements Generate and parse XML files Issue LDAP commands
The ever-expanding feature set of the PL/SQL language combined with
the wide array of supplied packages has yielded a powerful database
programming environment. Whether you are generating reports, writing
data loading scripts, or writing custom applications,
there's probably a place for PL/SQL in your project.
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