I have 2 tables:
I want to have a pointer into menu table as foreign key to pages.id. The problem is that some menu rows don't have a link to page. When someone clicks in the link opens a submenu. How i do this in phpmyadmin?
The match i want is 1 to 1 or 1 to 0
Maybe if i have a row to pages that has id=some_id with pages.body=null and all the menus that i want to have no submenu would have menu.pages_id=some_id Is this the right way to do that i want?
Using some magic value for
menu.pages_id doesn't work because that value whatever it is must exist on some row in the
The right way to do this is to make
menu.pages_id accept NULL. It's legal for a column to be nullable even if it's part of a UNIQUE constraint and a FOREIGN KEY constraint.
CREATE TABLE menu ( ... pages_id INT NULL, UNIQUE KEY (pages_id), FOREIGN KEY (pages_id) REFERENCES pages(pages_id) ) ENGINE=InnoDB;