How to write custom triggers, storage engines and triggers in MySQL using PHP-Mysql Tutorial-php.cn

How to write custom triggers, storage engines and triggers in MySQL using PHP

王林

Release： 2023-09-21 08:15:47

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How to write custom triggers, storage engines and triggers in MySQL using PHP

Introduction:
MySQL is a widely used open source relational database Management system, triggers and stored procedures are very important concepts in database development. This article will focus on how to use PHP to write custom triggers, storage engines and triggers in MySQL, while giving specific code examples.

1. Creation of a custom storage engine
The storage engine is a mechanism used to manage data in MySQL. You can create a custom storage engine in MySQL. The following is a sample code for using PHP to create a custom storage engine:

<?php
$connection = mysqli_connect("localhost", "root", "password");
if (!$connection) {
    die("Connection failed: " . mysqli_connect_error());
}

$query = "CREATE DATABASE my_database";
if (mysqli_query($connection, $query)) {
    echo "Database created successfully";
} else {
    echo "Error creating database: " . mysqli_error($connection);
}

$query = "USE my_database";
mysqli_query($connection, $query);

$query = "CREATE TABLE my_table (
    id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(30) NOT NULL,
    age INT(3) NOT NULL
)";
if (mysqli_query($connection, $query)) {
    echo "Table created successfully";
} else {
    echo "Error creating table: " . mysqli_error($connection);
}

$query = "CREATE TRIGGER my_trigger 
AFTER INSERT ON my_table
FOR EACH ROW
BEGIN
    INSERT INTO my_table_backup (id, name, age) 
    VALUES (NEW.id, NEW.name, NEW.age);
END";
if (mysqli_query($connection, $query)) {
    echo "Trigger created successfully";
} else {
    echo "Error creating trigger: " . mysqli_error($connection);
}

mysqli_close($connection);
?>

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2. Creation of custom triggers
A trigger is a special stored procedure defined in MySQL, which is stored in the database table It is automatically executed when the data in it changes. The following is a sample code for using PHP to create a custom trigger:

<?php
$connection = mysqli_connect("localhost", "root", "password");
if (!$connection) {
    die("Connection failed: " . mysqli_connect_error());
}

$query = "CREATE TRIGGER my_trigger
AFTER UPDATE ON my_table
FOR EACH ROW
BEGIN
    INSERT INTO my_table_audit (id, name, age, date_modified)
    VALUES (OLD.id, OLD.name, OLD.age, NOW());
END";
if (mysqli_query($connection, $query)) {
    echo "Trigger created successfully";
} else {
    echo "Error creating trigger: " . mysqli_error($connection);
}

mysqli_close($connection);
?>

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3. Creation of a custom stored procedure
A stored procedure is a collection of SQL statements predefined on the database server, which can be Simple calls execute these SQL statements. The following is a sample code for using PHP to create a custom stored procedure:

<?php
$connection = mysqli_connect("localhost", "root", "password");
if (!$connection) {
    die("Connection failed: " . mysqli_connect_error());
}

$query = "DELIMITER $$
CREATE PROCEDURE my_procedure()
BEGIN
    SELECT * FROM my_table;
END $$";
if (mysqli_multi_query($connection, $query)) {
    echo "Procedure created successfully";
} else {
    echo "Error creating procedure: " . mysqli_error($connection);
}

mysqli_close($connection);
?>

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Summary:
This article introduces how to use PHP to write custom triggers, storage engines and triggers in MySQL, and Corresponding code examples are given. The use of these technologies will provide more flexibility and scalability for database development, allowing developers to better meet business needs. In actual development, corresponding adjustments and optimizations need to be made according to specific business scenarios. Hope this article is helpful to you.

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