The Data Model - MongoDB Basics - page 41

Using Documents
Recall that a document consists of key-value pairs. For example, the pair "type" : "Book"
consists of a key named type , and its value, Book . Keys are written as strings , but the
values in them can vary tremendously. Values can be any of a rich set of datatypes,
such as arrays or even binary data. Remember: MongoDB stores its data in BSON format
(see Chapter 1 for more information on this topic).
Next, let's look at all of the possible types of data you can add to a document, and
what you use them for:
• String : This commonly used datatype contains a string of text
(or any other kind of characters). This datatype is used mostly for
storing text values (for example, "Country" : "Japan" }.
• Integer (32b and 64b) : This type is used to store a numerical value
(for example, { "Rank" : 1 } ). Note that there are no quotes
placed before or after the integer.
• Boolean : This datatype can be set to either TRUE or FALSE .
• Double : This datatype is used to store floating-point values.
• Min / Max keys : This datatype is used to compare a value against
the lowest and highest BSON elements, respectively.
• Arrays : This datatype is used to store arrays (for example,
[ "Membrey, Peter","Plugge, Eelco","Hows, David"] ).
• Timestamp : This datatype is used to store a timestamp. This can
be handy for recording when a document has been modified or
added.
• Object : This datatype is used for embedded documents.
• Null : This datatype is used for a Null value.
• Symbol : This datatype is used identically to a string; however, it's
generally reserved for languages that use a specific symbol type.
• Date * : This datatype is used to store the current date or time in
Unix time format (POSIX time).
• Object ID * : This datatype is used to store the document's ID.
• Binary data * : This datatype is used to store binary data.
• Regular expression * : This datatype is used for regular expressions.
All options are represented by specific characters provided in
alphabetical order. You will learn more about regular expressions
in Chapter 4.
• JavaScript Code * : This datatype is used for JavaScript code.