How do I implement cascade update

In MySQL, a cascade update can be implemented using foreign keys with the "ON UPDATE CASCADE" option. This means that if a primary key is updated in the parent table, the corresponding foreign keys in the child table will automatically be updated to reflect that change.

Example of Cascade Update in MySQL


        -- Creating a parent table
        CREATE TABLE departments (
            id INT PRIMARY KEY,
            name VARCHAR(50)
        );

        -- Creating a child table with foreign key referencing the parent table
        CREATE TABLE employees (
            id INT PRIMARY KEY,
            name VARCHAR(50),
            department_id INT,
            FOREIGN KEY (department_id) REFERENCES departments(id) ON UPDATE CASCADE
        );

        -- Inserting data into the parent table
        INSERT INTO departments (id, name) VALUES (1, 'Human Resources'), (2, 'IT');

        -- Inserting data into the child table
        INSERT INTO employees (id, name, department_id) VALUES (1, 'John Doe', 1), (2, 'Jane Smith', 2);

        -- Updating the primary key in the parent table
        UPDATE departments SET id = 3 WHERE id = 1;

        -- The corresponding foreign key in the child table will automatically be updated
        -- You can check the updated employees table
        SELECT * FROM employees;

How do I implement cascade update

Example of Cascade Update in MySQL

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How do I implement cascade update

Example of Cascade Update in MySQL

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