LEFT_SUBFIELD only supports Object
Ryan Mahoney
This message is for the benefit of anyone who sees this error in the future and to complain to the MongoDB devs ;)
If you see this error:
LEFT_SUBFIELD only supports Object
Most likely, if you look at the document you are attempting to update (via $set), one of your keys is empty, for example:
{
"_id" : ObjectId("4e52b5e08ead0e3853320000"),
"title" : "Something",
"url" : "http://www.website.org",
"" : "",
"tags" : [ "international"]
}
The only way I have corrected it is to update the entire document w/o the empty key remaining in the new replacement-document.
My question to the MongoDB devs is: why was this error even allowed to be inserted in the first place? How does something like this even happen?
Thanks!
-r
Aaron Westendorf
optimize saving of large documents by writing only the changes, but
we've encountered numerous differences between "$set" and "store" that
are making the transition quite painful (dotted key notation,
RIGHT_SUBFIELD and LEFT_SUBFIELD errors).
I worked around this bug by first calling "$unset" with {"":1} but now
we have a guarantee of 2 operations per save, whereas $unset was
conditional in my first implementation.
-Aaron
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Aaron Westendorf
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Agora Games
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Scott Hernandez
unfortunately update doesn't support this.
If you look at the bson spec you will see this is a valid field name.
http://bsonspec.org/#/specification
Aaron Westendorf
operate on a record where the empty-string key already exists. I was
able to successfully clear the empty key with $unset.
Glenn Maynard
There are many use-cases where "" can be used as a field name but
unfortunately update doesn't support this.
If you look at the bson spec you will see this is a valid field name.
http://bsonspec.org/#/specification
Glenn Maynard
Scott Hernandez
> On Fri, Mar 30, 2012 at 9:51 AM, Scott Hernandez <scotthe...@gmail.com>
> wrote:
>>
>> There are many use-cases where "" can be used as a field name but
>> unfortunately update doesn't support this.
>
>
> SERVER-2651/SERVER-5227 (fixed in 2.1)?
Yes, that is fixed in 2.1.0 so you won't get that error.
>> If you look at the bson spec you will see this is a valid field name.
>> http://bsonspec.org/#/specification
>
>
> Well, not all BSON documents are actually legal to store (eg. "." in key
> names).
Correct, and we try to keep that down to a minimum. The dot is really
a soft-limit as it just causes problems with queries/indexing. From
the server's point of view it doesn't really matter as long as you
don't reach into that field with some query/expression. We have found
it much easier for users/clients to simply not introduce this
confusion by disallowing it at that level.
> --
> Glenn Maynard
