Introduction to PL/SQL

PL/SQL stands for Procedural Language extension of SQL.

PL/SQL is a combination of SQL along with the procedural features of
programming languages. It was developed by Oracle Corporation in the early 90’s to
enhance the capabilities of SQL.

Advantages of PL/SQL

• Block Structures: PL SQL consists of blocks of code, which can be nested
  within each other. Each block forms a unit of a task or a logical module. PL/SQL
  Blocks can be stored in the database and reused.
• Procedural Language Capability: PL SQL consists of procedural language
  constructs such as conditional statements (if else statements) and loops like (FOR
  loops, WHILE loops).
• Better Performance: Without PL/SQL, Oracle must process SQL statements one
  at a time. Programs that issue many SQL statements require multiple calls to the
  database, resulting in significant network and performance overhead
• With PL/SQL, an entire block of statements can be sent to Oracle at one
  time. This can drastically reduce network traffic between the database and an
  application.
• PL/SQL stored procedures are compiled once and stored in executable
  form, so procedure calls are efficient. Because stored procedures execute in the
  database server, a single call over the network can start a large job. This division
  of work reduces network traffic and improves response times. Stored procedures
  are cached and shared among users, which lowers memory requirements and
  invocation overhead.
• Error Handling: PL/SQL handles errors or exceptions effectively during the
  execution of a PL/SQL program. Once an exception is caught, specific actions
  can be taken depending upon the type of the exception or it can be displayed
  to the user with a message.
• Full Portability: Applications written in PL/SQL can run on any operating
  system and platform where the Oracle database runs.
• Support for Developing Web Applications and Pages: You can use PL/SQL
  to develop Web applications and Server Pages (PSPs).