Re: Newbie help with ER diagrams

me wrote:
>Hi Jan Hidders. Thanks for the info.

You're welcome.

>It seems that ER diagrams don't really have a "standard" then, do they?

Nope, although there are some common elements that all share there are also lots of differences in notation (e.g. for the cardinalities of relations) and features (e.g. explicit aggregation relationships, multi-valued attributes, nested relationships, associative entities, multiple composite candidate keys, disjoint ISA relationships, et cetera). If you have to choose one, the best one is probably ORM, it has a formal semantics that is well-defined and has a very wide range of constraints that you can specify with a convenient graphical notation.

• Jan Hidders