how i can solve this issue

DROP child table first , DROP TABLE sales; DROP TABLE customers; DROP TABLE items; DROP TABLE companies; try it .

Hi Osama and Mahmoud! Thanks for reaching out. @:Mahmoud Thanks for sharing thiswith the Community! @:Osama As Mahmoud said, you should drop the table referenced by the foreign key. You should find the references, analyze and drop them as needed. Hope this helps. Best, Martin