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View page history| When we describe MongoDB as "document oriented", we mean it's in the class of databases for which the primary storage unit is a collection - possibly structured - of data, most likely as key/value pairs. |
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| Some examples of document formats are [JSON |http://www.json.org], XML, and simple sets of key/value pairs. For example the following "document" can be stored in Mongo DB: {code}{ author: 'joe', created: Date('03-28-2009'), title: 'Yet another blog post', text: 'Here is the text...', tags: [ 'example', 'joe' ], comments: [ { author: 'jim', comment: 'I disagree' }, { author: 'nancy', comment: 'Good post' } ] } {code} The Mongo database stores these JSON-style documents in a binary format called [BSON|DOCS:BSON]. MongoDB understands the internals of BSON objects \-\- not only can it store them, it can query on internal fields and index keys based upon them. For example the query {code} db.posts.find( { "comments.author" : "jim" } ) {code} is possible and means "find any blog post where at least one comment subjobject has author == 'jim'". |