Entity Relationship (E-R) diagrams questions
Q1. What does an E-R diagram show you?
Q2. What is the diagram to use for a 1-1 relationship?
Q3. What is the diagram to use for a 1-M relationship?
Q4. What is the diagram to use for a M-M relationship?
Q5. Why are M-M relationships not allowed in a relational database design?
Q6. How do you resolve a M-M relationship?
Q7. What is a simple primary key?
Q8. What is a compound primary key?
Q9. What is a foreign key?
Q10. After analysing the system and writing down a description of it, the following relationships were identified:
- Orders are places with a shop.
- An order can be for many different products.
- A product can appear on many different orders.
- Products are divided into two main categories, phones and accessories.
Draw the E-R diagram for the above analysis.
Q11. Write down the two sentences that describe this one-to-many relationship:
Q12. Look at the following diagram. Add some verbs/phrases in the correct places to help someone understand the diagram.
