TIP
After creating a public synonym, make sure the users of the synonym
have the correct privileges to the object referenced by the synonym.
When referencing a database object, Oracle first checks whether the object exists in the user??™s
schema. If no such object exists, Oracle checks for a private synonym. If there is no private synonym,
Oracle checks for a public synonym. If there is no public synonym, Oracle returns an error.
PL/SQL
Oracle PL/SQL is Oracle??™s procedural language extension to SQL. PL/SQL is useful when the
standard DML and select statements cannot produce the desired results in an easy fashion
because of the lack of the procedural elements found in a traditional third-generation language
such as C++ and Ada. As of Oracle9i, the SQL processing engine is shared between SQL and PL/
SQL, which means that all new features added to SQL are automatically available to PL/SQL.
In the next few sections, I??™ll take a whirlwind tour of the benefits of using Oracle PL/SQL.
Procedures/Functions
PL/SQL procedures and functions are examples of PL/SQL named blocks. A PL/SQL block is a
sequence of PL/SQL statements treated as a unit for the purposes of execution, and it contains up
to three sections: a variable declaration section, an executable section, and an exception section.
The difference between a procedure and function is that a function will return a single value
to a calling program such as a SQL select statement.
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