It must be a silly mistake but I can't find it.
When I run db.getCollection('communes').findOne({}),
I obtain:
{
"_id" : ObjectId("59b851a19db72301ae771c57"),
"COMMUNE" : "ALAA6",
"LIBGEO" : "ROHRBACH",
"PAYS" : "Allemagne"
}
which is fine.
But when I run db.getCollection('communes').findOne({COMMUNE: "ALAA6"}), it returns nothing!
For strange reasons, filtering on other fields work, so when I run db.getCollection('communes').findOne({LIBGEO: "ROHRBACH"}), it returns the result. Same thing filtering on "PAYS".
Adding quotes around COMMUNE, i.e. running db.getCollection('communes').findOne({"COMMUNE": "ALAA6"}) or using find instead of findOne doesn't change anything.
Any idea?
Ok, my fault. The collection has been created from an Excel export, and it seems the first column contains a strange character. Querying from the Robo3T client did not show it, but querying from Python returns:
{'LIBGEO': 'ROHRBACH',
'PAYS': 'Allemagne',
'_id': ObjectId('59b851a19db72301ae771c57'),
'\ufeffCOMMUNE': 'ALAA6'}
so obviously the \ufeffchar before COMMUNEshould be removed...
Related
There is an Mongo DB instance running on AWS so it is can be accessed only from terminal (I guess).
the table is called orders
to see what entries are in the table I'm using this command:
db.orders.find()
it returns a list of all orders. The problem comes when I want to delete one order. If entering in terminal db.orders. and than hit the tab it returns the list of all available commands.
One that I need I think it's db.orders.deleteOne() but I don't know what argument to send to it.
The order that must be deleted looks like this:
{ "_id" : ObjectId("5ea1a1c48a0c055870168770"), "display_id" : "WOW" }
so I tried with in many ways like:
db.orders.deleteOne(5ea1a1c48a0c055870168770)
db.orders.deleteOne("5ea1a1c48a0c055870168770")
db.orders.deleteOne(_id: 5ea1a1c48a0c055870168770)
db.orders.deleteOne("_id": "5ea1a1c48a0c055870168770")
but none of the seem to work.
db.orders.deleteOne( { "_id" : ObjectId("563237a41a4d68582c2509da") } );
I'm trying to check a collection to see if there is at least one documents that match a specific set of values.
I've tried reading the documentation at https://github.com/mongodb/mongo-go-driver#usage, but I can't seem to find much help there. I'm pretty new to MongoDB & Go, I believe that this is more a problem of my lack of experience.
Here is a sample query from Studio 3T that I'm trying to run with mongo-go-driver:
db.getCollection("events").find(
{
"event.eventType" : "OSR",
"context.vehicleId" : NumberInt(919514),
"ts" : {
"$gte" : ISODate("2019-06-21T21:38:43.022+0000")
}
}
).limit(1);
It seems that the context.FindOne method will do what I want (and eliminating the need for the .limit(1)). I thought that it would be straight forward to "port" this to Go and the mongo-go-driver.
I can sort of make this work, for example I have the following which will find me all the OSR:
var query = &bson.D{
{"event.eventType", "OSR"},
}
result := bson.D{}
e := collection.FindOne(context.TODO(), query).Decode(&result)
This will return me one document. Now, if I want to include the vehicleId value, and I update the query to:
var query = &bson.D{
{"event.eventType", "OSR"},
{"context.vehicleId", 919514},
}
No documents are returned. I haven't bother to expand query to include the ts field yet.
I would expect at to still have at least one document returned, but nothing is showing up. Does anybody have some tips, suggestions or guidance on what I'm doing wrong (or perhaps how I can do this better)?
Not quite sure, but have you tried with bson.M instead of bson.D?
It seems like it's working for me at least.
query := &bson.M{
"event.eventType": "OSR",
"context.vehicleId": 919514,
}
Please refer to the docs for more information.
Also, like #owlwalks said, are you sure, you're in the right collection?
After upgrade to 3.0 mongo driver i am receiving some new error on update request. For update like this:
db.table.update({_id: .... } , {$set : { "tags.Tag1" : true }});
I am receiving
cannot use the part (tags of tags.Tag1) to traverse the element ({tags: null})]]
The problem is that my updated document already contains default value for tags : null. If I manually remove it from document , update starts to work correctly. It is some new behavior for me , and it is happens after updating mongo driver from 2 to 3 ( not even database itself).
But now I wonder now how to avoid this error. I can of course check if "tags" already defined and only then make $set to element or the whole map. But it means 3 requests vs one old and the other problems like atomicity.
Although it's an old post but I think what you are looking for is the $ positional operator
I am guessing your "tags" is an array. So the above example could be something like
db.table.update({_id: .... } , {$set : { "tags.$.Tag1" : true }});
Hope it helps!
Yes, it can be updated... I had resolved similar problem
Resolved this
db.table.updateById({_id: .... } , {$set : { "levelSpecificData.scale.uom": "feet"}});
5b1f566ed65c7dcc34aaa7d5 MongoError: cannot use the part (scale of levelSpecificData.scale.uom) to traverse the element ({scale: false})
where in my collection 'levelSpecificData.scale' was a Boolean type T/F
I changed the default value type of levelSpecificData.scale to '{}' empty object... Surprisingly it worked fine after changing default values to object, since I want to treat scale as an object reference this solution was all good for it.
the following fails:
db.test.update({_id:102},{$pushAll:{our_days:["sat","thurs","frid"]}, country:"XYZ"}, {upsert:true})
error message: "Invalid modifier specified: country"
The correct way seems to be:
db.test.update({_id:102},{$pushAll:{our_days:["sat","thurs","frid"]}, $set:{country:"XYZ"}}, {upsert:true})
So is it the case that I cannot mix modifiers like "$pushAll" with simple assignments like field:value, in the same update document? Instead I have to use the $set modifier for simple assignments?
Is there anything in the docs that describes this behaviour?
This happens because db.test.update({_id : 1}, {country : 1}) will just change the whole document to country = 1 and thus removing everything else.
So most probably mongo being smart tells you: You want to update specific element and at the same time to remove everything (and that element as well) to substitute it with country = 1. Most probably this is not what you want. So I would rather rise an error.
Regarding the documentation - I think that the best way is to reread mongodb update.
There is extremely weird thing happening on my database. I have a query:
db.Tag.find({"word":"foo"})
this thing matches one object. it's nice.
Now, there's second query
db.Tag.find({$or: [{"word":"foo"}]})
and the second one does not give any results.
There's some kind of magic I obviously don't understand :( What is wrong in second query?
in theory, $or requires two or more parameters, so I can fake it with:
db.Tag.find({$or: [{"word":"foo"},{"word":"foo"}]})
but still, no results.
Your second query is perfectly fine, and it should work. Though the docs says, that $or performs logical operation on array of two or more expression, but it would work for single expression also.
Here's a sample that you can see, and try out, to get it to work: -
> db.col.insert({"foo": "Rohit"})
> db.col.insert({"foo": "Aman", "bar": "Rohit"})
>
> db.col.find({"foo": "Rohit"})
{ "_id" : ObjectId("50ed6bb1a401d9b4576417f7"), "foo" : "Rohit" }
> db.col.find({$or: [{"foo": "Rohit"}]})
{ "_id" : ObjectId("50ed6bb1a401d9b4576417f7"), "foo" : "Rohit" }
So, as you can see, both your query when used for my collection works fine. So, there is certainly something wrong somewhere else. Are you sure you have data in your collection?
Okaay, server admin installed mongodb from debian repo. Debian repo had 1.4.4 version of mongodb, aandd looks like $or is simply not yet supported out there :P