ER diagram and a Relational Schema

[john786]

I dont want answer, but i just need to get started. From where do i start?

 

 

 

Design a ER diagram and a relational schema for a message board.

 

Facts

1. Message board (or category)

2. Messages

3. Message replies

4. Topics

5. Topic replies

6. Topic watch

7. Users

 

Note:

1. A message must belong to one topic

2. A message board may belong to another message board

3. A topic must belong to one message board

4. A topic can have one or more messages

5. A user can send and receive a message

6. A user can create a topic

7. A user can request a topic watch on a specific topic

8. A user should have identifying features

[D H]

What do you think? We are not here to do your homework for you. That said, Some hints: What are the entities in this system? What are the relationships between them? The given information will help answer these questions.

[bascule]

I'm not sure why you're having trouble drawing an ER diagram given that description, short of you having no idea what an ER diagram is.

 

All the entities are spelled out. You need to draw lines between the entities with appropriate symbols for the types of relationships described. Start by drawing boxes for all the entities then add the lines. If you have some sense ahead of time of the important entities (users and messages in this case) they should be placed centrally within the diagram.