This week's book giveaway is in the OCAJP forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide 1Z0-808 and have Jeanne Boyarsky & Scott Selikoff on-line! See this thread for details.
I assume you are asking about the SQL table structure for storing these entity beans. As for the SQL part, there is no difference between bidirectional and unidirectional relations. You will have the same primary key/foreign key constraint in the tables, or you will have the same join table.
In other words, you will have primary keys in both tables and a foreign key in the many-side table that refers to the primary key of the one-side table.
Or, you will have a join table with two foreign key columns: one referring the primary key of the one-side table, the other referring the primary key of the many-side table.