What are the different types of PL/SQL program units that can be defined and stored in ORACLE database ? Procedures and Functions,Packages and Database Triggers. What are the advantages of having a Package ? Increased functionality (for example,global package variables can be declared and used by any proecdure in the package) and performance (for example all objects of the package are parsed compiled, and loaded into memory once) What are the uses of Database Trigger ? Database triggers can be used to automatic data generation, audit data modifications, enforce complex Integrity constraints, and customize complex security authorizations. What is a Procedure ? A Procedure consist of a set of SQL and PL/SQL statements that are grouped together as a unit to solve a specific problem or perform a set of related tasks. What is a Package ? A Package is a collection of related procedures, functions, variables and other package constructs together as a unit in the database. What is difference between Procedures and Functions ? A Function returns a value to the caller where as a Procedure does not. What is Database Trigger ? A Database Trigger is procedure (set of SQL and PL/SQL statements) that is automatically executed as a result of an insert in, update to, or delete from a table.
