问题
mongo code :
db.temperature.insert({"x":3,"y":4});
db.temperature.find();
OUTPUT { "_id" : ObjectId("52b418fb132c1f3236831447"), "y" : 4, "x" : 3 }
Please help me to understand why in my case(above.) The find method is showing Y value first and x value later even when while inserting the order is different.
Appreciate any help.
回答1:
Quoting https://stackoverflow.com/a/6453755/1150636
Both document structure and collection structure in MongoDB based on JSON principles. JSON is a set of key/value pairs (in particular fieldName/fieldValue for document and index/document for collection). From this point of view it doesn't seem that you can rely on order at all.
This means that there is no particular order that mongodb is required to return the fields of one record. You need to be ready to parse the results in whichever order they may be returned.
来源：https://stackoverflow.com/questions/20701412/order-of-key-values-in-mongodb