Begin with the question, what is your requirement? based on your question, you need to develope a relational database for managing movies data.
Before starting to build a database, you have to ask a lot of questions to understand about how the movies business work within the requirement scope. Lets start with the question,
Who is important to your movies business?
Based on the question, ACTOR, DIRECTOR.
What is important to movies business?
Now, the next question will be what is the definition of ACTOR, DIRECTOR, GENRES, MOVIES?
For example, An ACTOR is a human being, who acts in atleast one movie. Note that you should have a clear definition of entity (business concept) or else it will lead to multiple interpretation. (see here).
After understanding the business concepts, let us go for business rules. Some simple questions (based on your question).
- Can an Actor act in more than one Film?
- Can a Movie coontains more than one Actor?
- Can a Movie directed by more than one Director?
- Can a Movie categorized as more than one Genre?
Example business rule from your question.
- Each Actor can act in one or many Actor Movie.
- Each Actor Movie must be acted by one Actor.
- Each Movie can contain one or many Actor Movie.
- Each Actor Movie must belongs to one Movie.
- Each Directos can direct one or many Director Movie.
- Each Director Movie must be directed by one Director.
- Each Movie can contain one or many Director Movie.
- Each Director Movie must belongs to one Movie.
- Each Genres can contain one or many Genres Movie.
- Each Genres Movie must belongs to one Genres.
- Each Movie can contain one or many Genre Movie.
- Each Genre Movie must belongs to one Movie.
By applying these business rules, our new model may look like as follows:
This model is not normalized, after applying normalization (see here) process, you will have clear and detailed data model for your application.
I hope this model will help you to begin your assignment. Thank you.