HIGH PRODUCTIVITY
1) PL/SQL lets you write very compact code for manipulating data. In the same way that scripting languages such as PERL can read, transform, and write data from files, PL/SQL can query, transform, and update data in a database.
2) PL/SQL saves time on design and debugging by offering a full range of software-engineering features, such as exception handling, encapsulation, data hiding, and object-oriented data types.
3) PL/SQL extends tools such as Oracle Forms. With PL/SQL in these tools, you can use familiar language constructs to build applications. For example, you can use an entire PL/SQL block in an Oracle Forms trigger, instead of multiple trigger steps, macros, or user exits. PL/SQL is the same in all environments. After you learn PL/SQL with one Oracle tool, you can transfer your knowledge to other tools.
FULL PORTABILITY
Applications written in PL/SQL can run on any operating system and platform where the database runs. With PL/SQL, you can write portable program libraries and reuse them in different environments.
TIGHT SECURITY
PL/SQL stored subprograms move application code from the client to the server, where you can protect it from tampering, hide the internal details, and restrict who has access. For example, you can grant users access to a subprogram that updates a table, but not grant them access to the table itself or to the text of the UPDATE statement. Triggers written in PL/SQL can control or record changes to data, making sure that all changes obey your business rules.