A start$-$up video$/$film streaming company hired you to develop a database to help company$$s business operation. As a first step, you need to create an ER model to reflect the informatiDescribe and draw an example $($ER model$)$ of each of the following concepts $($The examples should NOT be the ones in textbook or discussed in class$/$ppt posted$)$

a$.$ a subtype$-$supertype structure

b$.$ a weak relationship

The company$$s primary business is prescription$-$based online streaming from a library of movies, including the ones produced in$-$house. So far the company has over $2$ million subscribers. The company needs to keep track of each subscriber$$s information such as account number, name, email address, credit card number, location, etc. It is important for the company to keep track of streaming activities for each subscriber $($account$).$ Because the company wants to know what movies a subscriber streamed in the past for analytics purpose. The company needs to keep track of the information of all movies in its collection, such as title of the movie, description, names of director and producer, year of production, etc. In recent years, the company produced some movies by itself. For each movie produced in$-$house, the company needs to know who are investors, if there is any, including their contact information, and amount of money they invested in a movie. The company also needs to keep track of the contact information $($name$,$ email, phone, etc.$)$ of all actors$/$actress who played roles in these movies. The manager needs to know which actor$/$actress is playing what role in a movie. Assuming each actor$/$actress can only play one role in a movie but an actor$/$actress can play in many movies. The payment to an actor$/$actress varies depending on the role and the movie he$/$she plays in$.$ A role in a movie can be identified$/$recognized by the title, year of the movie and the character$$s name.Describe and draw an example $($ER model$)$ of each of the following concepts $($The examples should NOT be the ones in textbook or discussed in class$/$ppt posted$)$

a$.$ a subtype$-$supertype structure

b$.$ a weak relationship