MySQL CREATE PROCEDURE

In MySQL, the CREATE PROCEDURE statement is used to define and create a stored procedure. Stored procedures are self-contained blocks of SQL code that are stored in the database and can be executed multiple times. They are often used to encapsulate complex SQL operations or to perform repetitive tasks.

Syntax

The basic syntax of the CREATE PROCEDURE statement is as follows:

CREATE PROCEDURE procedure_name(parameter_list)
BEGIN
    statements;
END;

procedure_name: The name of the stored procedure.
parameter_list: A list of parameters that the stored procedure can accept. Each parameter must have a name and a data type.
statements: The SQL code that the stored procedure will execute.

Parameter Types

There are three types of parameters:

IN: The parameter is passed into the stored procedure and can be used within the procedure.
OUT: The parameter is set by the stored procedure and can be used outside the procedure.
INOUT: The parameter is both passed into the stored procedure and set by the stored procedure. It can be used both within and outside the procedure.

Example

Here’s an example of a simple stored procedure that takes two parameters and inserts a record into a table:

DELIMITER //
CREATE PROCEDURE InsertEmployee(
    IN employee_name VARCHAR(255), 
    IN employee_salary DECIMAL(10,2)
)
BEGIN
    INSERT INTO employees (name, salary) 
    VALUES (employee_name, employee_salary);
END //
DELIMITER ;

In this example, the InsertEmployee stored procedure takes two input parameters (employee_name and employee_salary) and inserts a new record into the employees table.

Executing Stored Procedures

To execute a stored procedure, you can use the following syntax:

CALL procedure_name(parameter1, parameter2, ...);

For example, to execute the InsertEmployee stored procedure, you would use the following command:

CALL InsertEmployee('John Doe', 50000.00);

Benefits of Using Stored Procedures

There are several benefits to using stored procedures:

Encapsulation: Stored procedures encapsulate complex SQL operations and data access logic, making the code more modular and easier to maintain.

Reusability: Stored procedures can be reused multiple times, which can save time and improve code consistency.

Security: Stored procedures can be created with specific privileges, which can help to protect data from unauthorized access.

Improved performance: Stored procedures can be optimized for specific operations, which can improve database performance.

Conclusion

The CREATE PROCEDURE statement is a powerful tool for managing and automating tasks in MySQL databases. By using stored procedures, you can improve the performance, security, and maintainability of your database applications.