If you want an exact representation for financial purposes, then doubles or floating point values are unsuitable as the fractional parts are subject to rounding error. Certain decimal values cannot not be represented using binary-based floating points and must be approximated. For a less technical intro, see The trouble with rounding floating point numbers; if … Read more
… And, since 3.0.0, you can: import org.bson.Document; final Document doc = new Document(“myKey”, “myValue”); final String jsonString = doc.toJson(); final Document doc = Document.parse(jsonString); Official docs: Document.parse(String) Document.toJson()
First off, this actually is being raised in the next version to 8MB or 16MB … but I think to put this into perspective, Eliot from 10gen (who developed MongoDB) puts it best: EDIT: The size has been officially ‘raised’ to 16MB So, on your blog example, 4MB is actually a whole lot.. For example, … Read more
Although $date is a part of MongoDB Extended JSON and that’s what you get as default with mongoexport, I don’t think you can really use it as a part of the query. If try exact search with $date like below: db.foo.find({dt: {“$date”: “2012-01-01T15:00:00.000Z”}}) you’ll get the error: error: { “$err” : “invalid operator: $date”, “code” … Read more
db.messages.find( { headers : { From: “reservations@marriott.com” } } ) This queries for documents where headers equals { From: … }, i.e. contains no other fields. db.messages.find( { ‘headers.From’: “reservations@marriott.com” } ) This only looks at the headers.From field, not affected by other fields contained in, or missing from, headers. Dot-notation docs