Mongo Import type information

source: MongoDB Manual 2.6.4

JSON can only represent a subset of the types supported by BSON. To preserve type information, mongoimport accepts strict mode representation for certain types.

For example, to preserve type information for BSON types data_date and data_numberlong during mongoimport, the data should be in strict mode representation, as in the following:

{ "_id" : 1, "volume" : { "$numberLong" : "2980000" }, "date" : { "$date" : "2014-03-13T13:47:42.483-0400" } }

For the data_numberlong type, mongoimport converts into a float during the import.