modeling

Suppose I have 2 tables in a database. eg: Dog & Boss This is a many to many relationship, cause a boss can have more than 1 dog, and a dog can have more than 1 owner. I am the owner of Bobby, but so is my wife. But many to many is not allowed, so there is a helpertable: DogsPerBoss How to model this in code? Class Boss can have a collection of Dogs. Class Dog can have a collection of Bosses. --> at least, that is what I think. Perhaps there are better solutions? How about extra data that is in the helper-table? Should that be in de Boss-class or in the Dog-class? eg: Nickname (I call the dog

How would you model a system that handles permissions for carrying out certain actions inside an application? Security models are a large (and open) field of research. There's a huge array of models available to choose from, ranging from the simple: Lampson's Access control matrix lists every domain object and every principal in the system with the actions that principal is allowed to perform on that object. It is very verbose and if actually implemented in this fashion, very memory intensive. Access control lists are a simplification of Lampson's matrix: consider it to be something akin to a

Should I always have a primary key in my database tables? Let's take the SO tagging. You can see the tag in any revision, its likely to be in a tag_rev table with the postID and revision number. Would I need a PK for that? Also since it is in a rev table and not currently use the tags should be a blob of tagIDs instead of multiple entries of multiple post_id tagid pair? You should strive to have a primary key in any non-trivial table where you're likely to want to access (or update or delete) individual records by that key. Primary keys can consist of multiple columns, and formally speaking,

Can someone briefly explain the difference between a domain class diagram and a design class diagram? I found a explanation on Yahoo answers , but I find it quite confusing. A domain model is called conceptual model in database modeling, while a design model is called logical model . These distinctions are also used in model-driven development, where we have a succession of three types of models: (solution-independent) domain models resulting from domain/requirements engineering in the system analysis, or inception, phase of a development project (platform-independent) design models resulting

Which UML diagram is the best for showing dependency between our IT system and other external IT systems? For example I would like to show on diagram: system A gets data from system B system B can call some functionality from system A I'm wondering between component diagram and sequence diagram. What do you think? Components definitelly, and dependencies. Dependency does not go in direction of the data-flow, but from the component that "knows" other component (invokes something from it, creates an object, etc). The following diagram shows the idea. It is common (and highly recommendable)