Two tables having many to many relationship can not be linked together directly. They need a third table which is a link table / bridge table to link the two tables.
Ex – Table Book , Table Authors
A Book can have more than one author and an author can write more than one book.
To link these two tables a third table Book_Author is needed which stores the primary keys of the two tables as Foreign keys.
Table Book_Author Columns Book_ID(FK), Author_ID(FK)
All the existing combinations of Books and Authors are stored in this third table.
