I have a simple example:
conn = Connection()
db = conn.livestat
coll = db.cmn1
coll.insert({'test': 1 });
before insert collection autocreate. How to disable this function or add param to autocreate (for example I want to create a capped collection ) ?
You'll have to do it manually. See the doc.
db.createCollection("cmn1", {capped:true, size:100000})
You must create the capped collection before you write to it for the first time. Please use this function:
http://api.mongodb.org/python/current/api/pymongo/database.html#pymongo.database.Database.create_collection
Related
I have a collection in mongodb. In my python program, I have a variable named coll point at it. I want to create an index on a specified field, digestedOn, which will cause expiration of the record after 7776000 seconds.
I know how to create a simple index in python: coll.create_index([( "digestedOn", pymongo.ASCENDING)]). Where do I stick the {"expireAfterSeconds": 7776000} part?
Here's my whole program, I need the last line fixed so that the index is created with expireAfterSeconds.
import pymongo
import ssl
def connect_to_mongo(host, port, ssls, user, password, auth_source):
return pymongo.MongoClient(host, port, ssl=ssls, username=user, ssl_cert_reqs=ssl.CERT_NONE,
password=password, authSource=auth_source,
authMechanism='SCRAM-SHA-1', maxPoolSize=None)
client = connect_to_mongo(host="10.10.10.10", port=27017, ssls=True, user="user",
password="password",auth_source="admin")
db = client['logs']
colnames = db.list_collection_names()
coll = db[colnames[0]]
coll.create_index([( "digestedOn", pymongo.ASCENDING )])
Just pass it as a named parameter:
coll.create_index([( "digestedOn", pymongo.ASCENDING )], expireAfterSeconds=7776000)
I used InsertOne() for bulk insert.
user1 = InsertOne({"user_id": 1})
user2 = InsertOne({"user_id": 2})
collection.bulk_write([user1, user2])
If user_id = 1 already exist in collection, it throw batch op errors occurred errors.
I wonder that is there any method for only insert if data doesn't exist?
(Can't using get data and compare if data exist because I'm using bulk_write)
What you can do is : Use ReplaceOne with upsert:true. So that if the document already exists update wont have any effect, and if it doesn't exist, it will create the new document.
Try this:
user1 = ReplaceOne({"user_id": 1},{"user_id": 1},upsert = True)
user2 = ReplaceOne({"user_id": 2},{"user_id": 2},upsert = True)
collection.bulk_write([user1, user2])
Make sure you pass all the data you need to store in the User document, in the second argument of ReplaceOne
I am getting db is not defined when trying to use mongodb's distinct in meteor.
Template.displayinbox.helpers({
inboxlistings: function() {
itemscount = db.Messages.distinct( "fromUsername" ).count;
return db.Messages.distinct( "fromUsername" );
}
});
I want to be able to return only distinct documents in my collection from the username field and count all those documents that is posted by the fromUsername. How would I go about doing this in Meteor?
When you're querying anything in the Meteor code itself, you don't need to write db first. You have to use the variable name that used to instantiate the Mongo Object. Let's say you defined your Mongo db like this.
example = new Mongo.Collection('Messages');
then within your helper you just use the typical query using this object.
Template.displayinbox.helpers({
inboxlistings: function() {
var items = example.find();
return _uniq(items,function(i){return i.fromUserName;});
}
});
I have the following Mongoengine document:
class MyEmbed(EmbeddedDocument):
embedField = StringField(primary_key=True)
varField = StringField()
class TestDoc(Document):
myField = StringField()
embed_list = ListField(EmbeddedDocumentField(MyEmbed))
So I keep a list of embedded documents, to which I wish to add new documents if they don't exist already. The problem is that when I use the atomic update operator add_to_set things don't turn out the way I want them to.
This is what I am trying to do:
embed1 = models.MyEmbed(embedField="F1")
parent = models.TestDoc(myField="ParentField")
embed_list = []
embed_list.append(embed1)
parent.embed_list = embed_list
parent.save()
embed2 = models.MyEmbed(embedField="F1", varField="varField")
TestDoc.objects(id=parent.id).update_one(add_to_set__embed_list=embed2)
The problem is that after doing this, I have in the DB a list of embedded documents with 2 elements. And what I want is to decide upon one field (embedField in this case) whether 2 EmbeddedDocuments are equal or not, and not by taking into account all the properties. My questions are:
What are the default criteria according to which Mongoengine decides whether 2 EmbeddedDocuments are equal or not?
How can I redefine the function that makes Mongoengine decide when 2 EmbeddedDocuments are equal or not?
Thanks!
The actual checking is done inside MongoDB and not mongoengine.
The object sent to mongodb should be the same, but this is where it gets tricky as with BSON order is important and in python with dictionaries its not. When converting to send to mongodb mongoengine just passes a dictionary. This is a bug - so I've added #296 and will fix for 0.8
See https://github.com/MongoEngine/mongoengine/blob/master/mongoengine/document.py#L51 and https://github.com/MongoEngine/mongoengine/blob/master/mongoengine/base/document.py#L52:
def __eq__(self, other):
if isinstance(other, self.__class__):
return self._data == other._data
return False
It compare dicts of Embedded documents data. So you can override this method.
If you look at Document update that calls QuerySet update (find add_to_set and addToSet) you can find that mongoengine doesnt't check exists document in list and just call mongo $addToSet operation: https://github.com/MongoEngine/mongoengine/blob/master/mongoengine/queryset/transform.py#L156.
In your code you have document MyEmbed(embedField="F1") and try add another document MyEmbed(embedField="F1", varField="varField") so logic right: it add new document. If you try next code:
embed1 = models.MyEmbed(embedField="F1")
parent = models.TestDoc(myField="ParentField")
embed_list = []
embed_list.append(embed1)
parent.embed_list = embed_list
parent.save()
embed2 = models.MyEmbed(embedField="F1", varField="varField")
TestDoc.objects(id=parent.id).update_one(add_to_set__embed_list=embed2)
embed3 = models.MyEmbed(embedField="F1")
TestDoc.objects(id=parent.id).update_one(add_to_set__embed_list=embed3)
embed4 = models.MyEmbed(embedField="F1", varField="varField")
TestDoc.objects(id=parent.id).update_one(add_to_set__embed_list=embed4)
you can find that parent contains only embed1 and embed2.
So, to resolve you problem you can override __eq__ method and check document in list, but you must find another solution for update document list, because it have direct call of mongo method.
I'm doing a simple insert into Mongo...
db.notes.insert({ title: "title", details: "note details"})
After the note document is inserted, I need to get the object id immediately. The result that comes back from the insert has some basic info regarding connection and errors, but no document and field info.
I found some info about using the update() function with upsert=true, I'm just not sure if that's the right way to go, I have not yet tried it.
One of the cool things about MongoDB is that the ids are generated client side.
This means you don't even have to ask the server what the id was, because you told it what to save in the first place. Using pymongo the return value of an insert will be the object id. Check it out:
>>> import pymongo
>>> collection = pymongo.Connection()['test']['tyler']
>>> _id = collection.insert({"name": "tyler"})
>>> print _id.inserted_id
4f0b2f55096f7622f6000000
The answer from Tyler does not work for me.
Using _id.inserted_id works
>>> import pymongo
>>> collection = pymongo.Connection()['test']['tyler']
>>> _id = collection.insert({"name": "tyler"})
>>> print(_id)
<pymongo.results.InsertOneResult object at 0x0A7EABCD>
>>> print(_id.inserted_id)
5acf02400000000968ba447f
It's better to use insert_one() or insert_many() instead of insert(). Those two are for the newer version. You can use inserted_id to get the id.
myclient = pymongo.MongoClient("mongodb://localhost:27017/")
myDB = myclient["myDB"]
userTable = myDB["Users"]
userDict={"name": "tyler"}
_id = userTable.insert_one(userDict).inserted_id
print(_id)
Or
result = userTable.insert_one(userDict)
print(result.inserted_id)
print(result.acknowledged)
If you need to use insert(), you should write like the lines below
_id = userTable.insert(userDict)
print(_id)
Newer PyMongo versions depreciate insert, and instead insert_one or insert_many should be used. These functions return a pymongo.results.InsertOneResult or pymongo.results.InsertManyResult object.
With these objects you can use the .inserted_id and .inserted_ids properties respectively to get the inserted object ids.
See this link for more info on insert_one and insert_many and this link for more info on pymongo.results.InsertOneResult.
updated; removed previous because it wasn't correct
It looks like you can also do it with db.notes.save(...), which returns the _id after it performs the insert.
See for more info:
http://api.mongodb.org/python/current/api/pymongo/collection.html
some_var = db.notes.insert({ title: "title", details: "note details"})
print(some_var.inserted_id)
You just need to assigne it to some variable:
someVar = db.notes.insert({ title: "title", details: "note details"})
To get the ID after an Insert in Python, just do like this:
doc = db.notes.insert({ title: "title", details: "note details"})
return str(doc.inserted_id) # This is to convert the ObjectID (type of doc.inserted_id into string)