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Oracle Function

In Oracle FUNCTION is a set of Oracle statements you can call by name. The Oracle Procedure is very similar to Oracle Function, except that a function returns a value to the environment in which it is called. Use the CREATE FUNCTION statement to create a standalone stored function or a call specification.

Difference between Oracle Procedure and Oracle Function

Procedures

• Procedures can have input/output parameters.
• Procedure can return zero or n values.
• Procedures cannot be called from Function.

Functions

• Functions can have only input parameters.
• Function must return a value.
• Functions can be called from Procedure.

A function contains a header and a body.

Header: The header part consist of name of the function and the parameters passed to the function.

Body: The body part consist of a declaration section, execution section and exception section similar to a general Oracle block.

Pass parameters in function

There are three ways to pass parameters in function:

• IN parameters: Indicate that you must supply a value for the argument when calling the function.
• OUT parameters: Indicate that the function passes a value for this argument back to its calling environment after execution.
• INOUT parameters: Indicate that you must supply a value for the argument when calling the function and that the function passes a value back to its calling environment after execution.

Oracle Create Function Syntax

To create a function use CREATE OR REPLACE FUNCTION statement, use the following syntax:

Where:

function_name: The name of the function.

[OR REPLACE]: This option used to modify of an existing function.

parameter_name: The optional parameter list contains name, mode and types of the parameters.

return_datatype : The RETURN clause specifies the data type you are going to return from the function.

procedure-body: This part contains executable block.

IS | AS: The AS keyword is used instead of the IS keyword for creating a standalone procedure.

Oracle CREATE FUNCTION example

The following Oracle show how to create a function or a call specification:

Oracle Call Function example

The following Oracle show how to call above created function by passing required parameters along with the function name and if the function returns a value, then you can store the returned value:

Oracle Drop Function Syntax

To delete a function use DROP FUNCTION statement, use the following syntax:

Where:

function_name: The name of the function.

Oracle Drop Function example

The following Oracle statement show how to delete or drop existing Oracle function called "TotalUsers":

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