Oracle Database 10g SQL (Osborne ORACLE Press Series)

In this chapter, you learned that

• PL/SQL (Procedural Language/SQL) is built on top of SQL and is a third generation programming language.

• PL/SQL programs are divided up into blocks with each block containing PL/SQL and SQL statements.

• You may use a loop, such as a WHILE or FOR loop, to run one or more statements multiple times.

• You use a cursor when you have a SELECT statement that returns more than one row from the database. You retrieve the rows into the cursor using your SELECT statement and then fetch the rows from the cursor.

• Exceptions are used to handle errors that occur in your PL/SQL code.

• A procedure contains a group of SQL and PL/SQL statements. Procedures allow you to centralize your business logic in the database and may be used by any program that accesses the database.

• A function is similar to a procedure except that a function must return a value to the statement from which it is called.

• You can group procedures and functions together into packages, which allow you to encapsulate related functionality into one self-contained unit. Packages are typically made up of two components : a specification and a body.

A trigger is a procedure that is run automatically by the database when a specified SQL DML INSERT , UPDATE, or DELETE statement is run against a specified database table. Triggers are useful for doing things like advanced auditing of changes made to column values in a table.

In the next chapter, you ll learn about database objects.