retrieval of CouchDb get, can it be a set of documents?

Everyone, i am recently reading some knowledge about Couchdb just of interest. It's said that it stores data as pairs of index and document. and the document is literally a structure or javascript json structure.. Compared to relational database , couchdb is much lest complex, so, it saves re开发者_运维知识库ad/write time? right? But i am wondering, in reality, and some websites are implemented with couchdb, but not all websites can be right to use this db. and by the way, for retrieval of a result, just like relational db, it returns a set of data, Can couchdb return a set of documents. and can it return a document by a given condition?

Or it can only return a result by a given document id?

Thanx for your answer

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Compared to relational database , couchdb is much lest complex, so, it saves read/write time?

CouchDB stores individual documents in a key/value fashion which is less complex structure than RDBMS tables, but what it makes fast is it's MVCC model which offers high availability at expense of strong consistency.

Can couchdb return a set of documents. and can it return a document by a given condition? Or it can only return a result by a given document id?

Yes it can return document or a set of documents by a given condition through views. You can also get document directly through it's ID without creating a view or fetch multiple documents through CouchDB's HTTP bulk document API.