$7.$ Design a database for a $$Library$.$ Based on the following description. Draw the corresponding ER diagram by:

$$ Specifying the entities, their attributes, and their key attributes

$$ Specifying the relationships between entities, participation, and multiplicities of each relationship.

A library database contains information about books, authors of books, the subject of books and other information. Draw an ER diagram that describes the library database and make sure to write any assumptions you make and any constrains you think should hold. Make sure your assumptions are logical$.$

Each book is identified by a publishing number and has a title. Every author has a name, an SSN and a contact phone number and each author has at least one book that he wrote. All books are indexed by subjects where each subject has a subject title and subject number that identifies the subject. Every library carries a certain number of books, and each library has a name and a location $($City$).$

$8.$ Design a database for a $$Movie$.$ Based on the following description. Draw the corresponding ER diagram by:

$$ Specifying the entities, their attributes, and their key attributes

$$ Specifying the relationships between entities, participation, and multiplicities of each relationship.

A Movies database contains information about movies, stars of movies, the studios that own the movie and the director of each movie. Draw an ER diagram that describes the movies database and make sure to write any assumptions you make and any constrains you think should hold. Make sure your assumptions are logical$.$

Each movie is identified by a publishing year and a name. Every star has a name, an SSN and a gender and each star had acted in at least one movie. All studios are identified by their names and the database must keep track of the studios phone numbers and addresses. Every director has a name, a SNN$$and$$an$$address$.$