hello everybody,

I'm drawing an ER-diagram for an existing trading system. I'm just starting out and is deciding what entities should be included.

Now I have accounts and stocks, but then what should be the tables that store the orders? how about the portfolio table? and the interest settings table? should they be entities or relations? (and how?)

I only have very limited knowledge on drawing ER-diagram but do not have much time left, any suggestions and guidance will be greatly appreciated.

jimi

Entities are analogous to tables, so you will proably have an Order entity, Portfolio entity, etc.

Relationships (not "relations", which is a technical synonym for tables) are lines indicating how 2 entities are related. Typically a foreign key in the system will map to a relationship in the ERD.