Overview of Oracle Database and Development
or maintaining the database components of an application that uses the Oracle
technology stack. The discussion in this and following sections assumes that you, or
someone else in your organization, must know how to architect multiuser applications
(two tier or multitier) and understands the advantages of using a relational database
for the data persistence tier.
application requires, how to implement the rules for data integrity, and how to
implement the specified functions for accessing and manipulating the application
data.
program, and that the SQL language is that client program's interface to the Oracle
Database. You will learn how to access the Oracle Database by using two clients that
are packaged with the Oracle Database and designed for developers: SQL Developer
and SQL*Plus. Both allow you to issue the SQL statements you need in order to create
and test your application's database component without doing any client
programming. Programming such clients is outside the scope of this discussion.
define APIs that model business functions, and hide the implementation. Oracle
Database supports this practice by letting you specify the APIs as PL/SQL
subprograms. The implementation is tables, indexes, constraints, triggers, and the
various SQL statements that modify and fetch table rows. By embedding these SQL
statements in PL/SQL subprograms, and by using Oracle's schema and privilege
mechanisms, you can securely hide the implementation from the client programs.
Many of Oracle's major customers follow this practice strictly: client programs are
allowed to access the database only by calling PL/SQL subprograms. Some customers