Linking column with different tables - php

Question

Okay so I don't think it's possible but i'm asking to be sure. Let's say I have a table called wp_users and forum_users. In wp_users there's a username, email, and md5 hash column. Same thing goes with forum_users. Is there a way to syncronize the two so that way something like
INSERT INTO wp_users (username, password, email)
VALUES ('$_POST[username]', '$_POST[password]', '$_POST[email]');
would automatically do
INSERT INTO forum_users (username, password, email)
VALUES ('$_POST[username]', '$_POST[password]', '$_POST[email]');
Same with ALTER etc, etc.

Answer 1

Use transactions
BEGIN
INSERT INTO wp_users (username, password, email)
VALUES ('$_POST[username]', '$_POST[password]', '$_POST[email]');
INSERT INTO forum_users (username, password, email)
VALUES ('$_POST[username]', '$_POST[password]', '$_POST[email]');
COMMIT;

Answer 2

You can utilize MySQL TRIGGERS to automate this.
CREATE TRIGGER after_insert_wp_users
AFTER INSERT ON wp_users FOR EACH ROW
BEGIN
INSERT INTO forum_users (username, password, email)
VALUES (NEW.username, NEW.password, NEW.email);
END
You can do the same for UPDATE and other queries.
EDITED 1:
In case, both tables are required to be updated automatically, i.e. if a row is inserted in the table wp_users, it is automatically inserted in forum_users and vice versa, writing the second set of triggers to update wp_users table from forum_users will introduce recursive loop.
To circumvent this, we can use a status variable to check if secondary insert should happen or not.
Trigger 1:
CREATE TRIGGER after_insert_wp_users
AFTER INSERT ON wp_users FOR EACH ROW
BEGIN
IF #__disable_trigger_users = 1 THEN
SET #__disable_trigger_users = NULL;
ELSE
SET #__disable_trigger_users = 1;
INSERT INTO forum_users (username, password, email)
VALUES (NEW.username, NEW.password, NEW.email);
END IF;
END
Trigger 2:
CREATE TRIGGER after_insert_forum_users
AFTER INSERT ON forum_users FOR EACH ROW
BEGIN
IF #__disable_trigger_users = 1 THEN
SET #__disable_trigger_users = NULL;
ELSE
SET #__disable_trigger_users = 1;
INSERT INTO wp_users (username, password, email)
VALUES (NEW.username, NEW.password, NEW.email);
END IF;
END
EDITED 2
You can also achieve the same using MySQL Store Procedure.
DROP PROCEDURE IF EXISTS proc_insert_user
GO
CREATE PROCEDURE proc_insert_user
(
IN p_username VARCHAR(15),
IN p_password VARCHAR(15),
IN p_email VARCHAR(15)
)
BEGIN
INSERT INTO wp_users (username, password, email)
VALUES (p_username, p_password, p_email);
INSERT INTO forum_users (username, password, email)
VALUES (p_username, p_password, p_email);
END
GO
CALL proc_insert_user('$_POST[username]', '$_POST[password]', '$_POST[email]')
GO