• Using the mongo Shell >
• Data Types in the mongo Shell

Data Types in the mongo Shell

MongoDB BSON provide support for additional data types than JSON. Drivers provide native support for these data types in host languages and the mongo shell also provides several helper classes to support the use of these data types in the mongo JavaScript shell. See MongoDB Extended JSON for additional information.

Date

The mongo shell provides various options to return the date, either as a string or as an object:

• Date() method which returns the current date as a string.
• Date() constructor which returns an ISODate object when used with the new operator.
• ISODate() constructor which returns an ISODate object when used with or without the new operator.

Consider the following examples:

• To return the date as a string, use the Date() method, as in the following example:

  copy

  var myDateString = Date();
  

  • To print the value of the variable, type the variable name in the shell, as in the following:

    copy

    myDateString
    

    The result is the value of myDateString:

    copy

    Wed Dec 19 2012 01:03:25 GMT-0500 (EST)
    

  • To verify the type, use the typeof operator, as in the following:

    copy

    typeof myDateString
    

    The operation returns string.

• To get the date as an ISODate object, instantiate a new instance using the Date() constructor with the new operator, as in the following example:

  copy

  var myDateObject = new Date();
  

  • To print the value of the variable, type the variable name in the shell, as in the following:

    copy

    myDateObject
    

    The result is the value of myDateObject:

    copy

    ISODate("2012-12-19T06:01:17.171Z")
    

  • To verify the type, use the typeof operator, as in the following:

    copy

    typeof myDateObject
    

    The operation returns object.

• To get the date as an ISODate object, instantiate a new instance using the ISODate() constructor without the new operator, as in the following example:

  copy

  var myDateObject2 = ISODate();
  

  You can use the new operator with the ISODate() constructor as well.

  • To print the value of the variable, type the variable name in the shell, as in the following:

    copy

    myDateObject2
    

    The result is the value of myDateObject2:

    copy

    ISODate("2012-12-19T06:15:33.035Z")
    

  • To verify the type, use the typeof operator, as in the following:

    copy

    typeof myDateObject2
    

    The operation returns object.

ObjectId

The mongo shell provides the ObjectId() wrapper class around ObjectId data types. To generate a new ObjectId, use the following operation in the mongo shell:

copy

new ObjectId

See

ObjectId for full documentation of ObjectIds in MongoDB.

NumberLong

By default, the mongo shell treats all numbers as floating-point values. The mongo shell provides the NumberLong() class to handle 64-bit integers.

The NumberLong() constructor accepts the long as a string:

copy

NumberLong("2090845886852")

The following examples use the NumberLong() class to write to the collection:

copy

db.collection.insert( { _id: 10, calc: NumberLong("2090845886852") } )
db.collection.update( { _id: 10 },
                      { $set:  { calc: NumberLong("2555555000000") } } )
db.collection.update( { _id: 10 },
                      { $inc: { calc: NumberLong(5) } } )

Retrieve the document to verify:

copy

db.collection.findOne( { _id: 10 } )

In the returned document, the calc field contains a NumberLong object:

copy

{ "_id" : 10, "calc" : NumberLong("2555555000005") }

If you use the $inc to increment the value of a field that contains a NumberLong object by a float, the data type changes to a floating point value, as in the following example:

1. Use $inc to increment the calc field by 5, which the mongo shell treats as a float:

   copy

   db.collection.update( { _id: 10 },
                         { $inc: { calc: 5 } } )
   

2. Retrieve the updated document:

   copy

   db.collection.findOne( { _id: 10 } )
   

   In the updated document, the calc field contains a floating point value:

   copy

   { "_id" : 10, "calc" : 2555555000010 }
   

NumberInt

By default, the mongo shell treats all numbers as floating-point values. The mongo shell provides the NumberInt() constructor to explicitly specify 32-bit integers.

←   Getting Started with the mongo Shell Access the mongo Shell Help Information  →

© MongoDB, Inc 2008-present. MongoDB, Mongo, and the leaf logo are registered trademarks of MongoDB, Inc.