I have a collection with the _id field as a IP with type String.
I'm using mongoose, but here's the error on the console:
$ db.servers.remove()
$ db.servers.insert({"_id":"1.2.3.4"})
$ db.servers.insert({"_id":"1.2.3.5"}) <-- Throws dup key: { : null }
Likely, it's because you have an index that requires a unique value for one of the fields as shown below:
> db.servers.remove()
> db.servers.ensureIndex({"name": 1}, { unique: 1})
> db.servers.insert({"_id": "1.2.3"})
> db.servers.insert({"_id": "1.2.4"})
E11000 duplicate key error index: test.servers.$name_1 dup key: { : null }
You can see your indexes using getIndexes() on the collection:
> db.servers.getIndexes()
[
{
"v" : 1,
"key" : {
"_id" : 1
},
"ns" : "test.servers",
"name" : "_id_"
},
{
"v" : 1,
"key" : {
"name" : 1
},
"unique" : true,
"ns" : "test.servers",
"name" : "name_1"
}
]
I was confused by exactly the same error today, and later figured it out. It was because I removed a indexed property from a mongoose schema, but did not drop that property from the mongodb index. The error message is infact that the new document has an indexed property whose value is null (not in the json).
Related
I've created an index on two fields f1, f2 with db.test.createIndex({"f1":"text","f2":"text"},{unique:true})
{
"v" : 2,
"unique" : true,
"key" : {
"_fts" : "text",
"_ftsx" : 1
},
"name" : "f1_text_f2_text",
"ns" : "test.test",
"weights" : {
"f1" : 1,
"f2" : 1
},
"default_language" : "english",
"language_override" : "language",
"textIndexVersion" : 3
}
When I insert the two documents
db.test.insert({f1:"hello",f2:"there"})
db.test.insert({f1:"hello",f2:"there2"})
I get a duplicate key error
"E11000 duplicate key error collection: test.test index: f1_text_f2_text dup key: { : \"hello\", : 1.1 }"
however db.test.insert({f1:"hello2",f2:"there"}) works.
Are compound text indexes not supposed to work like regular compound indexes?
Are you sure that you want a unique text index?
If you create a standard compound index:
db.test.createIndex({"f1": 1, "f2": 1}, {unique: true})
Then the following inserts will all be successful:
db.test.insert({f1:"hello",f2:"there"})
db.test.insert({f1:"hello",f2:"there1"})
db.test.insert({f1:"hello",f2:"there2"})
And this insert will then fail with E11000 duplicate key error collection:
db.test.insert({f1:"hello",f2:"there"})
You don't have to create a text index in order to index string fields. A text index has a very specific role in supporting text searches but not all string searches require a text index. So, if you must ...
Facilitate 'quick' text matches covering both f1 and f2
Enforce uniqueness across f1 and f2
... then I suspect you will need to create two indexes:
db.test.createIndex({"f1":"text", "f2":"text"})
db.test.createIndex({"f1": 1, "f2": 1}, {unique: true})
I have a collection where I will have a _children attribute like this:
{
_children: {
videoTags: [ { id: '1', name: 'one'}, { id: '2', name: 'two'} ],
},
a: 10
}
Since I WILL search in videoTags, I create an index as such:
> db.test4.createIndex({ "_children.videosTags.id" : 1 }, { "unique" : true } );
{
"createdCollectionAutomatically" : false,
"numIndexesBefore" : 1,
"numIndexesAfter" : 2,
"ok" : 1
}
Trouble is, I can no longer add anything to that table since I get a duplicate index error. Here is how to reproduce it:
Step 1: insert to a collection
db.test4.insert({a:20})
WriteResult({ "nInserted" : 1 })
Step 2: make the index
db.test4.createIndex({ "_children.videosTags.id" : 1 }, { "unique" : true } );
{
"createdCollectionAutomatically" : false,
"numIndexesBefore" : 1,
"numIndexesAfter" : 2,
"ok" : 1
}
Step 3: try to insert again
db.test4.insert({a:30})
WriteResult({
"nInserted" : 0,
"writeError" : {
"code" : 11000,
"errmsg" : "insertDocument :: caused by :: 11000 E11000 duplicate key error index: wonder_1.test4.$_children.videosTags.id_1 dup key: { : null }"
}
})
I think the issue here is that there is already a record where _children.videoTags.id is not defined.
However, what I expected was a behaviour where if videoTags.id was specified, it needed to be unique. Instead, an empty one is considered a "taken" key.
What am I doing that is stupidly wrong?
This will work if you don't set unique as true, but I have the feeling I need to fix it for real...
There could be two reasons.
There could be other documents exists in collection with same _children.videosTags.id
It's quite possible that more than one document may have missing _children.videosTags.id" or having null value.
As you are creating unique key, null or empty values are give you tough time. Solution is either create sparse index and if your MongoDB version is 3.2+, create partial index. See documentation for partial indexes.
I'm trying to add a username field to documents in a 'users' collection, and I'd like it to be a unique index. (So far, we've been using email addresses for login but we'd like to add a username field as well.) However, running db.users.ensureIndex({username:1},{unique:true}) fails because mongo considers all the unset usernames to be duplicates and therefore not unique. Anybody know how to get around this?
Show the current users and username if they have one:
> db.users.find({},{_id:0,display_name:1,username:1})
{ "display_name" : "james" }
{ "display_name" : "sammy", "username" : "sammy" }
{ "display_name" : "patrick" }
Attempt to make the 'username' field a unique index:
> db.users.ensureIndex({username:1},{unique:true})
{
"err" : "E11000 duplicate key error index: blend-db1.users.$username_1 dup key: { : null }",
"code" : 11000,
"n" : 0,
"connectionId" : 272,
"ok" : 1
}
It doesn't work because both james and sammy have username:null.
Let's set patrick's username to 'patrick' to eliminate the duplicate null value.
> db.users.update({display_name: 'patrick'}, { $set: {username: 'patrick'}});
> db.users.ensureIndex({username:1},{unique:true})
> db.users.getIndexes()
[
{
"v" : 1,
"key" : {
"_id" : 1
},
"ns" : "blend-db1.users",
"name" : "_id_"
},
{
"v" : 1,
"key" : {
"username" : 1
},
"unique" : true,
"ns" : "blend-db1.users",
"name" : "username_1"
}
]
Now it works!
To clarify the question, what I'd like is to be able to make username a unique index without having to worry about all the documents that have username still set to null.
Try creating a unique sparse index:
db.users.ensureIndex({username:1},{unique:true,sparse:true})
As per the docs:
You can combine the sparse index option with the unique indexes option
so that mongod will reject documents that have duplicate values for a
field, but that ignore documents that do not have the key.
Although this only works for documents which don't have the field, as opposed to documents that do have the field, but where the field has a null value.
I can't remove the _id index, why?
When I try running the dropIndexes command, it removes all indexes but not the _id index.
Doing 'db.runCommand' doesn't work either:
> db.runCommand({dropIndexes:'fs_files',index:{_id:1}})
{ "nIndexesWas" : 2, "errmsg" : "may not delete _id index", "ok" : 0 }
not ok.
Can i use a field including _id in a composite index?
I couldn't find anything online, the ensureindex command can't do it.
db.fs_files.ensureIndex({'_id':1, 'created':1});
the above command just created a new composite index. i haven't found some similar 'create Index' command.
the default _id index is a unique index?
the getIndexes returns it's not a unique index.
{
"v" : 1,
"key" : {
"_id" : 1
},
"ns" : "gridfs.fs_files",
"name" : "_id_"
},
{
"v" : 1,
"key" : {
"created" : 1
},
"unique" : true,
"ns" : "gridfs.fs_files",
"name" : "created_1"
}
There is a createIndex command in addition to ensureIndex also.
E.g.
db.<coll>.createIndex({foo:1})
You cannot delete the index on "_id" in mongodb.
Please see the documentation here
When I call ensureIndex from the mongo shell on a collection for a compound index an _id field of type ObjectId is auto-generated in the index object.
> db.system.indexes.find();
{ "name" : "_id_", "ns" : "database.coll", "key" : { "_id" : 1 } }
{ "_id" : ObjectId("4ea78d66413e9b6a64c3e941"), "ns" : "database.coll", "key" : { "a.b" : 1, "a.c" : 1 }, "name" : "a.b_1_a.c_1" }
This makes intuitive sense as all documents in a collection need an _id field (even system.indexes, right?), but when I check the indexes generated by morphia's ensureIndex call for the same collection *there is no _id property*.
Looking at morphia's source code, it's clear that it's calling the same code that the shell uses, but for some reason (whether it's the fact that I'm creating a compound index or indexing an Embedded document or both) they produce different results. Can anyone explain this behavior to me?
Not exactly sure how you managed to get an _id field in the indexes collection but both shell and Morphia originated ensureIndex calls for compound indexes do not put an _id field in the index object :
> db.test.ensureIndex({'a.b':1, 'a.c':1})
> db.system.indexes.find({})
{ "v" : 1, "key" : { "_id" : 1 }, "ns" : "test.test", "name" : "_id_" }
{ "v" : 1, "key" : { "a.b" : 1, "a.c" : 1 }, "ns" : "test.test", "name" : "a.b_1_a.c_1" }
>
Upgrade to 2.x if you're running an older version to avoid running into now resolved issues. And judging from your output you are running 1.8 or earlier.