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PL SQL programming is Oracle's
Procedural Language extension to SQL. Realizing the
benefit of supplementing SQL with a good, cross-platform
programming language, Oracle introduced Procedural Language/SQL,
or (PL/SQL). PL/SQL is a more complete language that
would run inside Oracle's database server, tightly integrated
not just with SQL syntax but also with the internal
gears and pinions of the database itself. It, too, usually
runs on the database server, but some Oracle products
such as Developer/2000 also contain a PL/SQL engine
that resides on the client. Therefore, run your PL/SQL
code on either the client or the server depending on
which is more appropriate for the task at hand.
Unlike SQL, PL SQL programming
is procedural. This means that your code specifies exactly
how things get done. As in SQL, however, you need some
way to send your PL/SQL code up to the server for execution.
PL/SQL also enables you to embed SQL statements within
its procedural code. This tight-knit relationship between
PL/SQL, SQL, and SQL*Plus is the cause for some of the
confusion between the products.
PL SQL programming is commonly
used to write data-centric programs to manipulate data
in an Oracle database. In PL/SQL, language syntax, structure
and data types are similar to that of ADA.If you want
your programs to exploit the special capabilities of
Oracle software, you'll need to know the language well.
PL/SQL programming provides a mechanism for developers
to add a procedural component at the server level. It
has been enhanced to the point where developers now
have access to all the features of a full-featured procedural
language at the server level. It also forms the basis
for programming in Oracle's continually evolving set
of client/server development tools, most notably Developer/2000.
If you start doing PL SQL programming,
you are in all likelihood surprised by the abundance
of functionality in PL/SQL. Most people tend to think
of it as SQL plus some "other stuff." To emphasize
this point, here is a list of some of its other stuff:
- Control structures (if-then-else, case statements,
various types of loops).
- Means of creating reusable procedures and functions.
- Packages to bundle related procedures, functions,
and declarations into a single, reusable programming
unit.
- Record and array-like data structures.
- Support for object-oriented programming.
- Built-in utility packages that let you do things
like send Internet email, read and write from operating
system files, and fetch Web pages via HTTP.
- Tools to create entire Web sites using PL/SQL.
- Facilities for calling out to C and Java programs.
- A small but growing body of open source code
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