Grouping views in design documents in CouchDB

What is the difference between views as a stand-alone design 开发者_Go百科documents and views grouped in one design document? When do you put two views in one design document? Is there any guide for this?

There's no real guide for this, as it's entirely up to you. Here are the implications as far as I can tell:

Each design document can have as many (or as few) views as you wish. Keep in mind that a view is not created or updated until it is first queried. Also, when a single view is queried, all the other views in that same design document will also be created/updated. This won't be a problem unless you have millions of documents, but it is something to bear in mind.

Also, I believe the full string value of the view is compared between revisions, so it won't rebuild a view if the name and function text are identical. (NOTE this is speculation based on what I've read about views, it's just never explicitly stated)

Generally, I've migrated towards having a "common" design document that contains a lot of the core CommonJS modules (like form validation functions) and other general settings. In addition, each "entity" in my project will have a separate design document with their own views, update handlers, validation functions, show/list functions, etc. This pattern keeps each entity and it's functions grouped together, almost like a class of sorts. I've found it is much easier to maintain and naming is a little easier when each entity is self-contained.