Function & procedure
- 1. POWERPOINT PRESENTATION ON PROCEDURE & FUNCTION
- 2. Procedures A procedure is a block of statements enclosed by some declaration statement with control blocks and a matching declaration. All executable statements is must be written by some procedure.
- 3. Why to Create a Procedure It allow you to break your program into discrete logical units, each of which can be debug more easily than an entire program without procedures. It can also use as a building block for other programs. If you have code that performs the same task in different places, you can write the task once as a procedure and then call it from different places in your code.
- 4. Types of Sub Procedure General Procedure It tells the application how to perform a specific task. It may invoke another application (function). Event Procedure Event procedures execute in response to an event raised by user action or by an occurrence in a program such as click event of an object.
- 5. Function A Function is a series of statements enclosed by the certain module (of that system) and End Function statements. The Function procedure performs a task and then returns control to the calling code. When it returns control, it also may return a value to the calling module.
- 6. Parts of a Function A Function has these parts: Name Anything you like as long as it starts with a letter and contains only letters numbers and underscores. (without any space). Argument List a list of the items of data that the function needs. Return Type if the type is Function this tells the compiler what kind of thing will be returned, for instance, single row or multi-row , group by etc. Body all the statements that do the work is as sub procedure.
- 7. Passing by value (By Value): The procedure gets a copy of the actual value of the argument. function (number x) Passing by reference (By Reference): The procedure gets access to the argument's actual memory address. function (number & x ) When a by reference parameter is used, the value of the passed argument can be permanently changed by the procedure.
- 8. Example of Procedure declare a number; b number; c number; begin a:=&a; b:=&b; c:=a+b; dbms_output.put_line('a+b:'); dbms_output.put_line(c); end;/
- 9. Example of Function Procedure Some of the commonly used aggregate functions are : • SUM • COUNT • AVG • MIN • MAX declare c number; begin select avg(sal) into c from EMPLOYEE; dbms_output.put_line(c); end; /
- 10. Bibliography • guidance from teachers •internet •books and other friends This is presented to you by: Avishek Chatterjee & Aatish Kumar Upaddhay