Details
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Type:
Bug
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Status:
Open
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Priority:
Major - P3
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Resolution: Unresolved
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Affects Version/s: 1.4.0
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Fix Version/s: 2.7 desired
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Component/s: Shell
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Labels:None
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Environment:linux
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Backport:No
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# Replies:10
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Last comment by Customer:true
Description
I am finding that a unique index is not applied to multiple elements of an array in the same document of a collection. They are only applied between documents in a collection.
More details available at: http://groups.google.com/group/mongodb-user/browse_thread/thread/56bf4f84f7cad835
Is this intended behavior? Is there a way around it?
Activity
Wasn't aware of this ticket, there is a small thread on this at stack-overflow.
http://stackoverflow.com/questions/9390590/mongodb-indexing-embedded-fields-dot-notation
Also, it seems this should fail but doesn't:
db.foo.insert({a:[
{b:1},
{b:1}]})
I wrote a post about unique indexes @ http://joegornick.com/2012/10/25/mongodb-unique-indexes-on-single-embedded-documents/
I also have some proposed solutions for declaring single document unique indexes and would love to get some feedback!
+1 for the issue and for either of Joe's solutions. Those both feel very natural.
I was able to use a workaround, you can "normalize" the data
$db.bar.find()
{_id: 10, foo: 1, b:1}
{_id: 11, foo: 1, b:2}
{_id: 12, foo: 1, b:3}
$db.foo.find()
{_id: 1, bar:[10,11,12]}
Then you can
- use $addToSet on foo.bar to manage unique items
- add compound key bar
{foo,b}
to restrict duplicates
- use upsert on bar collection to easily add new items or update existing ones. trick is to read the return from the upsert use that in the $addToSet operation on foo
from
SERVER-1069Should it be possible to enforce uniqueness of an object within an array within a single document using a unique index?
For instance:
db.foo.save( { a : [
{ b : 1 }] } )
{unique: true}db.foo.ensureIndex({_id: 1, 'a.b': 1},
);
// This succeeds. Should it fail?
{b: 1}db.foo.update({}, { '$push' : { 'a':
} });