I have the following code that drops a key item successfully:
get_image.update(unset__item=1)
This drops the key item. However, I would like this only to drop when item has a field promotion that is set to true:
"item" : [
{
"promotion" : "true
}
]
is there any way to check this using unset?
Something like this should do the trick.
collection.update_many({ “item”: { “promotion”: True }, { “$unset”: { “item”: 1 } })
Alternatively, if you’re trying to delete all documents which have a true promotion field:
collection.delete_many({ “item”: { “promotion”: True } })
Related
I have a JSON response in python like this:
{
"response" : [
{
"section1" : [
{
"test1" : "324d",
"test2" : "433",
},
{
"item" : "trousers",
"color" : "red",
"apply" : [ "never", "exclude" ]
},
{
"price" : "277",
"tax" : "29",
"apply" : [ "all", "single" ]
}
],
"site_id" : "38477d",
}
]
}
How can I get the price from the part that has apply value of all?
I have been able to manually grab it like this..
result['response']['section1'][2]['price']
But it changes position in the section each time, how can I search for it instead so that the position does not matter?
UPDATE
To clarify, the all will only ever appear once and it will always be in section1
Search in the list for dicts that have a key called "apply" and then check that key "all" is in that dict:
[dic['price'] for dic in test['response'][0]['section1'] if 'apply' in dic and 'all' in dic['apply']][0]
sec = result["response"][0]["section1"]
print([x for x in sec if "apply" in x and "all" in x["apply"]][0]["price"])
For example, if this is my record
{
"_id":"123",
"name":"google",
"ip_1":"10.0.0.1",
"ip_2":"10.0.0.2",
"ip_3":"10.0.1",
"ip_4":"10.0.1",
"description":""}
I want to get only those fields starting with 'ip_'. Consider I have 500 fields & only 15 of them start with 'ip_'
Can we do something like this to get the output -
db.collection.find({id:"123"}, {'ip*':1})
Output -
{
"ip_1":"10.0.0.1",
"ip_2":"10.0.0.2",
"ip_3":"10.0.1",
"ip_4":"10.0.1"
}
The following aggregate query, using PyMongo, returns documents with the field names starting with "ip_".
Note the various aggregation operators used: $filter, $regexMatch, $objectToArray, $arrayToObject. The aggregation pipeline the two stages $project and $replaceWith.
pipeline = [
{
"$project": {
"ipFields": {
"$filter" : {
"input": { "$objectToArray": "$$ROOT" },
"cond": { "$regexMatch": { "input": "$$this.k" , "regex": "^ip" } }
}
}
}
},
{
"$replaceWith": { "$arrayToObject": "$ipFields" }
}
]
pprint.pprint(list(collection.aggregate(pipeline)))
I am unaware of a way to specify an expression that would decide which hash keys would be projected. MongoDB has projection operators but they deal with arrays and text search.
If you have a fixed possible set of ip fields, you can simply request all of them regardless of which fields are present in a particular document, e.g. project with
{ip_1: true, ip_2: true, ...}
I have a structure like this:
{
"id" : 1,
"user" : "somebody",
"players" : [
{
"name" : "lala",
"surname" : "baba",
"player_place" : "1",
"start_num" : "123",
"results" : {
"1" : { ... }
"2" : { ... },
...
}
},
...
]
}
I am pretty new to MongoDB and I just cannot figure out how to extract results for a specific user (in this case "somebody", but there are many other users and each has an array of players and each player has many results) for a specific player with start_num.
I am using pymongo and this is the code I came up with:
record = collection.find(
{'user' : name}, {'players' : {'$elemMatch' : {'start_num' : start_num}}, '_id' : False}
)
This extracts players with specific player for a given user. That is good, but now I need to get specific result from results, something like this:
{ 'results' : { '2' : { ... } } }.
I tried:
record = collection.find(
{'user' : name}, {'players' : {'$elemMatch' : {'start_num' : start_num}}, 'results' : result_num, '_id' : False}
)
but that, of course, doesn't work. I could just turn that to list in Python and extract what I need, but I would like to do that with query in Mongo.
Also, what would I need to do to replace specific result in results for specific player for specific user? Let's say I have a new result with key 2 and I want to replace existing result that has key 2. Can I do it with same query as for find() (just replacing method find with method replace or find_and_replace)?
You can replace a specific result and the syntax for that should be something like this,
assuming you want to replace the result with key 1,
collection.updateOne({
"user": name,
"players.start_num": start_num
},
{ $set: { "players.$.results.1" : new_result }})
I have this Document in mongo engine:
class Mydoc(db.Document):
x = db.DictField()
item_number = IntField()
And I have this data into the Document
{
"_id" : ObjectId("55e360cce725070909af4953"),
"x" : {
"mongo" : [
{
"list" : "lista"
},
{
"list" : "listb"
}
],
"hello" : "world"
},
"item_number" : 1
}
Ok if I want to push to mongo list using mongoengine, i do this:
Mydoc.objects(item_number=1).update_one(push__x__mongo={"list" : "listc"})
That works pretty well, if a query the database again i get this
{
"_id" : ObjectId("55e360cce725070909af4953"),
"x" : {
"mongo" : [
{
"list" : "lista"
},
{
"list" : "listb"
},
{
"list" : "listc"
}
],
"hello" : "world"
},
"item_number" : 1
}
But When I try to pull from same list using pull in mongo engine:
Mydoc.objects(item_number=1).update_one(pull__x__mongo={'list': 'lista'})
I get this error:
mongoengine.errors.OperationError: Update failed (Cannot apply $pull
to a non-array value)
comparising the sentences:
Mydoc.objects(item_number=1).update_one(push__x__mongo={"list" : "listc"}) # Works
Mydoc.objects(item_number=1).update_one(pull__x__mongo={"list" : "listc"}) # Error
How can I pull from this list?
I appreciate any help
I believe that the problem is that mongoengine doesn't know the structure of your x document. You declared it as DictField, so mongoengine thinks you are pulling from DictField not from ListField. Declare x as ListField and both queries should work just fine.
I suggest you should also create an issue for this:
https://github.com/MongoEngine/mongoengine/issues
As a workaround, you can use a raw query:
Mydoc.objects(item_number=1).update_one(__raw__={'$pull': {'x.mongo': {'list': 'listc'}}})
My items store in MongoDB like this :
{"ProductName":"XXXX",
"Catalogs" : [
{
"50008064" : "Apple"
},
{
"50010566" : "Box"
},
{
"50016422" : "Water"
}
]}
Now I want query all the items belong to Catalog:50008064,how to?
(the catalog id "50008064" , catalog name "Apple")
You cannot query this in an efficient manner and performance will decrease as your data grows. As such I would consider it a schema bug and you should refactor/migrate to the following model which does allow for indexing :
{"ProductName":"XXXX",
"Catalogs" : [
{
id : "50008064",
value : "Apple"
},
{
id : "50010566",
value : "Box"
},
{
id : "50016422",
value : "Water"
}
]}
And then index :
ensureIndex({'Catalogs.id':1})
Again, I strongly suggest you change your schema as this is a potential performance bottleneck you cannot fix any other way.
This should probably work according to the entry here, although this won't be very fast, as stated in in the link.
db.products.find({ "Catalogs.50008064" : { $exists: true } } )