Does Key order matter in a MongoDB BSON doc?
Question
I know certain commends need the hashmap / dictionary to be ordered, but does the actual BSON document in MongoDB matter and would the index still work?
E.g.
db.people.ensureIndex({LName:1, FName:1});
Would it work on both:
{LName:"abc", FName:"def"},
{FName:"ghi", LName:"jkl"}
?
Thanks
Solution
The order of a document's properties does not affect indexing.
You can see this for yourself by running this query:
db.people.find({LName: "abc"}).explain()
and then this query:
db.people.find({LName: "jkl"}).explain()
you should see that MongoDB will use the index in both cases (the cursor
property should be something like "BtreeCursor LName_1_FName_1"
).
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