Is it possible to use something like 'exists' in a Mongo query to return this record based on an ID?
Something like select where 'ids' contains key '123456'?
{
"department": "Digging",
"ids": {
"123456": {
"color": "blue"
},
"123457": {
"color": "red"
}
}
}
As you're searching for the existence of a field with a given name, $exists is the operator you need (see Advanced Queries).
e.g. something like:
db.YourCollection.find({ "ids.123456" : {$exists: true}});
Related
I’ve been trying to update the data in my mongoDB.
I want to update all products with a new productName field.
my data looks something like:
{
"id": "12345",
"products": [{
"id": 0
"productCode": "test",
"status": "PENDING",
},
{
"id": 1
"productCode": "test",
"status": "COMPLETE",
}],
}
When I try the following. I get this error The positional operator did not find the match needed from the query.
db.customers.updateMany(
{ id: "12345" },
{ $set: {
"products.$.productName": "Name here" }
}
)
If I do account.0.productName then it’s fine and updates. I’m not sure why $ is not working for me
db.customers.updateMany(
{ id: "12345" },
{ $set: {
"products.0.productName": "Name here" }
}
)
Positional operator is not working because you are not using the array into the find (first object)
If you try this query it will work as expected because you have the position finding by products.id.
Otherwise, if you don't have the position into array where update, yo can't use $ operator in this way. You need this query:
db.collection.update({
"id": "12345",
},
{
"$set": {
"products.$[].newField": "test2"
}
},
{
"multi": true
})
Mongo playground example here
Using $[] you can reference the array and add the value into each object.
$[] docs here
It says:
The all positional operator $[] indicates that the update operator should modify all elements in the specified array field.
That's exactly we want :)
I've a bunch of documents that look like:
{
"ids": [{"name":"aa", "age":1}, {"name":"bb", "age":2}]
}
I'd like to be able to query my documents providing a collection of ids, something like
db.getCollection('Collection').find({"ids":{$in : [{"name":"aa", "age":1}, {"name":"bb", "age":2}]}})
Generally that works, however it breaks when the fields order is changed, so for example I cannot find documents when I execute the following query
db.getCollection('Collection').find({"ids":{$in : [{"age":1,"name":"aa"}, { "age":2, "name":"bb"}]}})
I know that I could try to always execute a query with fields "in order", but from my current task perspective it's not always possible. Any help with that ?
You need $elemMatch when you want to run your query against an array of objects:
db.col.find({ $or: [ { "ids": { $elemMatch: {"age":1,"name":"aa"} } }, { "ids": { $elemMatch: { "age":2, "name":"bb"} } } ] })
Mongo Playground
EDIT: you can decide whether $or or $and should be a top level operator (depending on your use case)
While trying to update a MongoDB document using Mongoose, can I use a findById() with a save() in the callback, or should I stick with traditional update methods such as findByIdAndModify, findOneAndModify, update(), etc.? Say I want to update the name field of the following document (please see a more elaborate example in the edit at the end, which motivated my question):
{
"_id": ObjectId("123"),
"name": "Development"
}
(Mongoose model name for the collection is Category)
I could do this:
Category.update({ "_id" : "123" }, { "name" : "Software Development" }, { new: true })
or I could do this:
Category.findById("123", function(err, category) {
if (err) throw err;
category.name = "Software Development";
category.save();
});
For more elaborate examples, it feels easier to manipulate a JavaScript object that can simply be saved, as opposed to devising a relatively complex update document for the .update() operation. Am I missing something fundamentally important?
Edited 7/21/2016 Responding to the comment from #Cameron, I think a better example is warranted:
{
"_id": ObjectId("123"),
"roles": [{
"roleId": ObjectId("1234"),
"name": "Leader"
}, {
"roleId": ObjectId("1235"),
"name": "Moderator"
}, {
"roleId": ObjectId("1236"),
"name": "Arbitrator"
}]
}
What I am trying to do is remove some roles as well as add some roles in the roles array of sub-documents in a single operation. To add role sub-documents, $push can be used and to remove role sub-documents, $pull is used. But if I did something like this:
Person.update({
"_id": "123"
}, {
$pull : {
"roles" : {
"roleId" : {
$in : [ "1235", "1236" ]
}
}
},
$push : {
"roles" : {
$each: [{
"roleId" : ObjectId("1237"),
"name" : "Developer"
}]
}
}
}
When I try to execute this, I get the error Cannot update 'roles' and 'roles' at the same time, of course. That's when I felt it is easier to find a document, manipulate it any way I want and then save it. In that scenario, I don't know if there is really any other choice for updating the document.
I typically like to use findById() when I am performing more elaborate updates and don't think you are missing anything fundamentally important.
However one method to be aware of in mongoose is findByIdAndUpdate(), this issues a mongodb findAndModify update command and would allow you to perform your first example with the following code: Category.findByIdAndUpdate("123", function(err, savedDoc) {...}).
I have this object and I'd like to update the name field "field" of all the document in the collections. I read the mongodb documentation and it says $rename doesn't work in this case. I should execute a forEach but I don't know how which command use
{
"name": "foo"
"array": [
"object": {
"field": "name"
}
]
}
Do it manually:
db.collection.find().forEach(function(doc) {
if (doc.array) {
doc.array.forEach(function(edoc) {
if (edoc.object) {
doc.object.new_field = edoc.object.field
delete edoc.object.field
}
})
db.test.update({ "_id" : doc._id }, doc)
}
})
This should get you started. It handles missing or empty array arrays, but not an array value of the wrong type, or an object value of the wrong type.
$rename modifier for update Ops should work (http://docs.mongodb.org/manual/reference/operator/update/rename/)
Imagine a collection like yours:
{
"name": "foo",
"array":[
{"field": "name" }
]
}
You will be able to do something like this:
db.rename.update({},{$rename:{"name":"newName"}});
And the document will be as follows:
{
"newName": "foo",
"array":[
{"field": "name" }
]
}
In order to update all the collection you should use the multi option as follows:
db.rename.update({},{$rename:{"name":"newName"}}, {multi:true})
Regards
I have a collection with nested documents in it. Each document also has an _id field.
Here's an example of a documents structure
{
"_id": ObjectId("top_level_doc"),
"title": "Cadernos",
"parent": "4fd55bbc5d1709793b000008",
"criterias": {
"0": {
"_id": ObjectId("a_nested_doc"),
"value": "caderno",
"operator": "contains",
"field": "design0"
}
}
}
I want to be able to find the nested document just by searching it's _id
With this query
{
"criterias._id" : ObjectId("a_nested_doc")
}
It returns the parent document (i just want the one that's nested).
Ideally I would do this
{
"_id" : ObjectId("a_nested_doc")
}
And it would return the document with that id (either its nested or not).
Ps. I edited the "_id" values for the sake of simplicity just for this example.
You may have to live with selecting criterias._id (without writing a wrapper around the query, at least), but you can select the document itself by simply retrieving a subset of the fields.
http://www.mongodb.org/display/DOCS/Retrieving+a+Subset+of+Fields
// The simplest case converted to your use case
db.collection.find( { criterias._id : ObjectId("a_nested_doc") }, { criterias : 1 } );