I have a BasicDBObject which while debugging seems to hold:
{ "_id" : { "p_key" : { "$date" : "2012-02-02T00:00:00Z"} , "d_key" : 222} , "t_key" : 10195 , "w_key" : 4 , "f_key" : { "$date" : "2012-02-02T00:00:00Z"}}
Now, when I try:
dbObject.get("_id.d_key"));
I get a null pointer exception.
Any thoughts on what I am doing wrong here?
I am trying to get the value of d_key inside _id.
DBObject and it's children do not support dot notation gets. You will have to do :
if(dbObject.containsField("_id"))
((DBOBject)dbObject.get("_id")).get("p_key")
That's an extremely large _id field by the way. It will result in huge indexes which is generally not a good idea.
Related
Hello I need some help with MongoDB:
My Document has the following property (generated by an Map with spring):
"filter":{"billingAccount_id":["multisim5"],"simulate":["true"]}
and i'm trying to find the document with the this code (generated by spring)
query.addCriteria(Criteria.where("filter").all(getMapWithValues()));
which results in
"filter" : { "$all" : [{ "billingAccount_id" : ["multisim5"] }] }
but i'm getting no result. What's to do here?
Thanks for help in advance
You're applying $all on an object (filter) instead of an array (filter.billingAccount_id). Change your request (and method getMapWithValues) to get something like :
{"filter.billingAccount_id" : { "$all" : ["multisim5"] }}
BUT $all is used to find array that contains, at least, all values provided in query. Since there's an unique element in $all param, $all is useless here, and the following query output the same result :
{"filter.billingAccount_id" : "multisim5"}
EDIT : if you want to query array with exact match ("multisim5" and nothin else), use the following :
{"filter.billingAccount_id" : { "$eq" : ["multisim5"] }}
Sample json object :
{ "_id" : ObjectId( "55887982498e2bef5a5f96db" ),
"a" : "x",
"q" : "null",
"p" : "",
"s" : "{\"f\":{\"b\":[\"I\"]},\"time\":\"fs\"}" }
need all documents where time = fs
My query :
{"s":{"time" : "fs"}}
above returns zero products but that is not true.
There are two problems here. First of all s is clearly a string so your query cannot work. You can use $regex as below but it won't be very efficient:
{s: {$regex: '"time"\:"fs"'}}
I would suggest converting s fields to proper documents. You can use JSON.parse to do it. Documents can be updated based on a current value using db.foo.find().snapshot().forEach. See this answer for details.
Second problem is your query is simply wrong. To match time field you should use dot notation:
{"s.time" : "fs"})
I'm trying to find records in MongoDB that are created outside a specific period. The query to search for records inside a specific period is pretty straightforward:
db.test.find({"Published":{'$gt':"2011-08-02", '$lt':"2011-08-06"}})
So naturally, I tried this for "outside" a specific range:
db.test.find({'$not':{"Published":{'$gt':"2011-08-02", '$lt':"2011-08-06"}}})
But this returns an empty result, while there are definately records published then.
What query should I use instead? Can anyone help me? I'm using raw mongo queries.
Thanks in advance
--- UPDATE ---
I found that the following query works, but it doesn't look like the perfect solution:
db.test.find(
{'$or': [
{"Published":{'$lt':"2011-02-02"}},
{"Published":{'$gt':"2011-08-06"}}
]}
)
Is there a cleaner way to do it?
You are putting the $not in the wrong place. Try this:
db.test.find({"Published":{ $not:{$gt:"2011-08-02", $lt:"2011-08-06"} } })
For details, see the MongoDB docs about the $notoperator.
Edit as because of the comment this solution would not work:
> db.dates.find()
{ "_id" : ObjectId("5492d46ef6226b581c80c0a2"), "a" : 1, "date" : "2011-08-04" }
{ "_id" : ObjectId("5492d4e2f6226b581c80c0a3"), "a" : 2, "date" : "2011-08-07" }
> db.dates.find({date:{$not:{$gt:"2011-08-02",$lt:"2011-08-06"}}})
{ "_id" : ObjectId("5492d4e2f6226b581c80c0a3"), "a" : 2, "date" : "2011-08-07" }
Gurus - I'm stuck in a situation that I can't figure out how I can query from the following collection "spouse", which has embedded document "surname" and check for equality with "surname" of this document:
{
"_id" : ObjectId("50bd2bb4fcfc6066b7ef090d"),
"name" : "Gwendolyn",
"surname" : "Davis",
"birthyear" : 1978,
"spouse" : {
"name" : "Dennis",
"surname" : "Evans",
"birthyear" : 1969
},
I need to query:
Output data for all spouses with the same surnames (if the surname of
one of the spouses is not specified, assume that it coincides with the
name of another)
I tried something like this:
db.task.find( {"surname" : { "spouse.surname" : 1 }} )
but it failed)
PLEASE PLEASE Guide me how I can achieve this any example/sample? based on this will be really helpful :-)
Thanks a lot!
You have three options.
Use $where modifier:
db.task.find({$where: 'this.spouse.surname === this.surname'})
Update all your documents and add special flag. After that you will be able to query documents by this flag. It's faster then $where, but requires altering your data.
Use MapReduce. It's quite complicated, but it allows you to do nearly anything.
I have a Mongo find query that works well to extract specific fields from a large document like...
db.profiles.find(
{ "profile.ModelID" : 'LZ241M4' },
{
_id : 0,
"profile.ModelID" : 1,
"profile.AVersion" : 2,
"profile.SVersion" : 3
}
);
...this produces the following output. Note how the SVersion comes before the AVersion in the document even though my projection asked for AVersion before SVersion.
{ "profile" : { "ModelID" : "LZ241M4", "SVersion" : "3.5", "AVersion" : "4.0.3" } }
{ "profile" : { "ModelID" : "LZ241M4", "SVersion" : "4.0", "AVersion" : "4.0.3" } }
...the problem is that I want the output to be...
{ "profile" : { "ModelID" : "LZ241M4", "AVersion" : "4.0.3", "SVersion" : "3.5" } }
{ "profile" : { "ModelID" : "LZ241M4", "AVersion" : "4.0.3", "SVersion" : "4.0" } }
What do I have to do get the Mongo JavaScript shell to present the results of my query in the field order that I specify?
I have achieved it by projecting the fields using aliases, instead of including and excluding by 0 and 1s.
Try this:
{
_id : 0,
"profile.ModelID" :"$profile.ModelID",
"profile.AVersion":"$profile.AVersion",
"profile.SVersion":"$profile.SVersion"
}
I get it now. You want to return results ordered by "fields" rather the value of a fields.
Simple answer is that you can't do this. Maybe its possible with the new aggregation framework. But this seems overkill just to order fields.
The second object in a find query is for including or excluding returned fields not for ordering them.
{
_id : 0, // 0 means exclude this field from results
"profile.ModelID" : 1, // 1 means include this field in the results
"profile.AVersion" :2, // 2 means nothing
"profile.SVersion" :3, // 3 means nothing
}
Last point, you shouldn't need to do this, who cares what order the fields come-back in.
You application should be able to make use of the fields it needs regardless of the order the fields are in.
Another solution I applied to achieve this is the following:
db.profiles
.find({ "profile.ModelID" : 'LZ241M4' })
.toArray()
.map(doc => ({
profile: {
ModelID: doc.profile.ModelID,
AVersion: doc.profile.AVersion,
SVersion: doc.profile.SVersion
}
}))
Since version 2.6 (that came out in 2014) MongoDB preserves the order of the document fields following the write operation (source).
P.S. If you are using Python you might find this interesting.