Self-join Questions

I have a mysql table (menu_items) of items used to build a menu. see data below. each menu item is either a parent or a child. items with a

I have two tables: table a: name value

Our database is on sql server 2014. i had the exact same issue as

I have an existing innodb table which already has foreign keys pointing to different tables. but when i try to create a foreign key

I have a specific scenario to track the in and out times for an inventory item. i have a inventory_track table of the following format