Documents

MongoDB stores data records as BSON documents. BSON is a binary representation of JSON documents.

{
field1: value1,
field2: value2,
field3: value3,
...
fieldN: valueN
}

The value of a field can be any of the BSON data types, including other documents, arrays, and arrays of documents. For example, the following document contains values of varying types:

var mydoc = {
               _id: ObjectId("5099803df3f4948bd2f98391"),
               name: { first: "Alan", last: "Turing" },
               birth: new Date('Jun 23, 1912'),
               death: new Date('Jun 07, 1954'),
               contribs: [ "Turing machine", "Turing test", "Turingery" ],
               views : NumberLong(1250000)
            }

The above fields have the following data types:

_id holds an ObjectId.
name holds an embedded document that contains the fields first and last.
birth and death hold values of the Date type.
contribs holds an array of strings.
views holds a value of the NumberLong type.