You can index and query JSON documents by using views. Views are functions written in JavaScript that can serve several purposes in your application. You can use them to:

• Find all the documents in your database that you need for a particular process

• Create a copy of data in a document and present it in a specific order

• Create an index to efficiently find documents by a particular value or by a particular structure in the document

• Represent relationships between documents

• Perform calculations on data contained in documents. For example, if you use documents to represent users and user points in your application, you can use a view to find the ten users that have the top scores.

This chapter will describe how you can do the following using Couchbase SDKs and view functions:

• Extract and order specific data,

• Creating an index and use it to perform efficient document lookups,

• Retrieve a range of entries, and

• Perform a reduce function, which computes a value based on entry values.

For additional information about views, see Views and indexes.