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If I create a conceptual class diagram such that each class captures 'name' and 'attributes' but not 'operations', have I not basically created what would be otherwise considered an ERD? I'm trying to gain an understanding of what the differences are between creating a conceptual class diagram as I have described versus calling it a ERD? If these are still two different animals, can somebody please explain what the differences are?
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ER diagrams represent the abstract representation of the data model, while class diagrams represent the static structure and behavior of the proposed system.
BOTH diagrams serve quite DIFFERENT purposes: ERD: to make mere mortal end-users (and business owners) UNDERSTAND the model of a given business solution; and DATA SCHEMA: a "blueprint" used by DBAs to BUILD databases, and by DEVELOPERS to CONSUME the data in that database.
It's not in UML specification. You can download specification PDF from the link. UML is a common notation/language for object oriented modeling and it includes a multitude of diagram types. ERD is a diagram for data modeling (attributes and relationships).
The main difference between analysis class diagrams and design class diagram is the analysis phase focus on designing a class diagram without concerning about the implementation detail. where as, desgin modelling concern with the implementaion and architechture since, it the high-level static view of the system.
The class diagram contains just the classes in your object model with eventual links/relationships connecting diagram elements. However those links don't necessarily correspond to physical relationships like in an ERD diagram, but instead they represent logical connections.
The class diagram is just the object model of your application and does not contain any persistence-specific information. When you think about the class diagram forget about the database or any other storage you may use.
The ERD diagram on the other side, is a persistence-specific diagram which display the entities (tables) existing in a (most often) relational database. It also displays the physical relations (and cardinalities) between those tables and all other database-specific information. The ERD diagram can sometimes look similar to the class diagram, but that doesn't mean is the same as a class diagram.
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