Stored procedure in php w3schools

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Stored Procedures are created to perform one or more DML operations on Database. It is nothing but the group of SQL statements that accepts some input in the form of parameters and performs some task and may or may not returns a value. 

Syntax : Creating a Procedure 
 

CREATE or REPLACE PROCEDURE name(parameters)
IS
variables;
BEGIN
//statements;
END;

The most important part is parameters. Parameters are used to pass values to the Procedure. There are 3 different types of parameters, they are as follows: 
 

1. IN: 
   This is the Default Parameter for the procedure. It always receives the values from calling program.
2. OUT: 
   This parameter always sends the values to the calling program.
3. IN OUT: 
   This parameter performs both the operations. It Receives value from as well as sends the values to the calling program.

Example: 

Imagine a table named with emp_table stored in Database. We are Writing a Procedure to update a Salary of Employee with 1000. 
 

CREATE or REPLACE PROCEDURE INC_SAL(eno IN NUMBER, up_sal OUT NUMBER)
IS
BEGIN
UPDATE emp_table SET salary = salary+1000 WHERE emp_no = eno;
COMMIT;
SELECT sal INTO up_sal FROM emp_table WHERE emp_no = eno;
END; 

• Declare a Variable to Store the value coming out from Procedure : 

VARIABLE v NUMBER;

• Execution of the Procedure: 
   

EXECUTE INC_SAL(1002, :v);

• To check the updated salary use SELECT statement: 
   

 SELECT * FROM emp_table WHERE emp_no = 1002;

• or Use print statement : 
   

PRINT :v

Pl sql stored procedure:

The pl sql stored procedure is a named PL/SQL block which performs one or more specific tasks. A pl sql stored procedure can be divided into two parts: Header and Body part.
Header: The header part contains the name of the procedure and the parameters passed to the procedure.
Body: The body part contains declaration section, execution section and exception section.
Note: A pl sql stored procedure do not return a value directly.

How to pass parameter in a procedure?

We can use the below modes to pass the parameters in a procedure:
IN-parameters: These parameters are the read-only parameters. Procedure cannot change the value of IN parameters.
OUT-parameters: These parameters are the write-only parameters and used to return values back to the calling program. Procedure can change the value of OUT parameters.
IN OUT-parameters: These parameters are read and write parameters i.e. a procedure can reads and change the IN OUT parameter value and return it back to the calling program.

Syntax of pl sql stored procedure:

CREATE [OR REPLACE] PROCEDURE proc_name [list of parameters] 
IS | AS    
   //Declaration block 
BEGIN    
   //Execution block 
EXCEPTION    
  //Exception block 
END;

How to create a procedure?

Procedure example without parameters:

CREATE OR REPLACE PROCEDURE hello_world
AS
BEGIN
   dbms_output.put_line('Hello World!');
END;
/

Procedure example with parameters:

CREATE OR REPLACE PROCEDURE add_student(rollNo IN NUMBER, name IN VARCHAR2)
IS 
   BEGIN 
    insert into students values(rollNo,name);
  END;
/

How to execute stored procedure?

A procedure can be executed by using EXEC or EXECUTE statement.

EXEC procedure_name();
EXEC procedure_name;

Note: Execute procedure with parameters:

EXEC procedure_name(param1,param2…paramN);

A procedure can also be invoked from other PL SQL block.

BEGIN
   procedure_name;
END;
/

How to drop stored procedure?

DROP PROCEDURE procedure_name;