I am facing an issue in deleting an array from db.
I want to delete the [2] array with its id as condition.
I have tried many things, but none give results as expected.
db.users.update({ '_id': ObjectId("53689fa45bac9757f81fbb77")},{ '$pull' : { 'injury._id': ObjectId("5379974ac76d005c2d00005c") } })
Use the $pull operator to remove the element you do not want:
db.collection.update(
{ "injury._id": ObjectId("53760d9820b6ee683000005c") },
{
"$pull": {
"injury": { "_id": ObjectId("53760d9820b6ee683000005c") }
}
}
)
Forgive me if the actual _id values do not match as you posted a screenshot.
I guess, something like this should work
.update(..., { $pull: { injury: {_id: YOUR_ID } } })
The format of $pull is
$pull: { arrayName: { array item query } }
You can use unset() if you're using PHP
Related
there is a nested mongodb document that looks like the image below. I want to do a search in the body field in this document, but I could not succeed. how can i do this search. thanks in advance
I tried to search like this. Is my path correct?
const result = await this.campaignModel.find({
"sequencesPageData": {
"$elemMatch": {
"mailSteps": {
"$elemMatch": {
"mailTemplate": x
}
}
}
}
});
I did a search like this but got no results.
const result = await this.campaignModel.find({
"sequencesPageData": {
"$elemMatch": {
"mailSteps": {
"$elemMatch": {
"mailTemplate": x
}
}
}
}
});
For object fields, simply access them using dot notation. For array fields, use $elemMatch to perform the match.
db.collection.find({
"sequencesPageData.mailSteps": {
"$elemMatch": {
"mailTemplate": {
"$elemMatch": {
"subject": "asdf"
}
}
}
}
})
Mongo Playground
If you are only testing a single field in the array, there is no need to use $elemMatch, you can use dot notation:
db.collection.find({ "sequencesPageData.mailSteps.mailTemplate.body": "x" })
$elemMatch is useful to ensure that 2 or more tests are satisfied by the same array element, but since this example uses only 1 test, it works without.
I'm using mongoDB version 3.2. and i want to check if a string is exist in an array of string, i want to use the regex so if just a part of the given string is exist in a string in the array, that record should be returned.
here's an example of a record:
{
name: "initiative 1",
portfolioItems: ["Non clinical", "ITS portfolio", "Lean"]
}
the following query does not work:
db.collection.aggregate([
{
$match:
{ 'portfolioItems' : { $in: [/term/] } }
}
])
is there anyway to achieve that ?
Try this one.
db.collection.aggregate([
{
$match:
{"portfolioItems":{'$regex':"^it", '$options': 'i'}}
}
])
The symbol ^ used to start from the first of string. If u don't need it. You can remove it.
Your query become
{
$match:
{"portfolioItems":{'$regex':"^"+term, '$options': 'i'}}
}
You have to match the pattern in each element of array.
Try this :
{ 'portfolioItems' : { $regex: [/term/] } }
Here is my collection:
{
"_id":"5b3385af20b7dc2b008ef5b9",
"name":"C",
"distances":[{"_id":"5b3460b05b2edc1bbcb0f362",
"distance":7,
"waypoint":"5b3385af20b7dc2b008ef5b9",
"status":"available"},
{"_id":"5b3460b05b2edc1bbcb0f361",
"distance":4,
"waypoint":"5b3460a15b2edc1bbcb0f360",
"status":"available"}],
"createdAt":"2018-06-27T12:40:15.457Z",
"updatedAt":"2018-06-27T12:57:50.191Z",
"__v":0
}
Let's focus on the distances array only, so which is:
"distances":[{"_id":"5b3460b05b2edc1bbcb0f362",
"distance":7,
"waypoint":"5b3385af20b7dc2b008ef5b9",
"status":"available"},
{"_id":"5b3460b05b2edc1bbcb0f361",
"distance":4,
"waypoint":"5b3460a15b2edc1bbcb0f360",
"status":"available"}]
What i want to do is, I want to delete object and update the distances array which have "waypoint":"5b3460a15b2edc1bbcb0f360"
so far I have tried:
Model.update( {'_id': model._id}, { $pullAll: {distances: [{'waypoint': req.body.id}] } });
this isn't working. Please suggest a way out.
You can use $pull of MongoDB
db.collection.update(
{ },
{ $pull: { distances: { waypoint: req.body.id} } },
)
{multi: true}: adding this in above query will delete all entries matching { waypoint: req.body.id}
I am have manually created an object in a Mongo collection:
{
"messages": [
{
"url":"http://test.test.com",
"message":"test message"
}
],
....other properties
}
I would like to add an _id:ObjectId() to each item of my messages array and for each document in the collection.
I tried:
collection.update({}, {
$set: {
'messages.$._id': ObjectId(),
},
}, { multi: true }
but this is not working. The Id is getting added when I add new ones going through Mongoose, but these were manually entered into mongo. Any help is appreciated.
Your syntax is correct, but in order to use the $ positional operator the array field must appear as part of the query document, check in documentation.
Try this:
db.collection.update({messages: {$exists: true }},
{$set: { 'messages.$._id': ObjectId() } },
{multi: true}
)
I just upgraded to Mongo 2.6.1 and one update statement that was working before is not returning an error. The update statement is:
db.post.update( { 'answers.comments.name': 'jeff' },
{ '$set': {
'answers.$.comments.$.name': 'joe'
}},
{ multi: true }
)
The error I get is:
WriteResult({
"nMatched" : 0,
"nUpserted" : 0,
"nModified" : 0,
"writeError" : {
"code" : 2,
"errmsg" : "Too many positional (i.e. '$') elements found in path 'answers.$.comments.$.createUsername'"
}
})
When I update an element just one level deep instead of two (i.e. answers.$.name instead of answers.$.comments.$.name), it works fine. If I downgrade my mongo instance below 2.6, it also works fine.
You CAN do this, you just need Mongo 3.6! Instead of redesigning your database, you could use the Array Filters feature in Mongo 3.6, which can be found here:
https://thecodebarbarian.com/a-nodejs-perspective-on-mongodb-36-array-filters
The beauty of this is that you can bind all matches in an array to a variable, and then reference that variable later. Here is the prime example from the link above:
Use arrayFilters.
MongoDB 3.5.12 extends all update modifiers to apply to all array
elements or all array elements that match a predicate, specified in a
new update option arrayFilters. This syntax also supports nested array
elements.
Let us assume a scenario-
"access": {
"projects": [{
"projectId": ObjectId(...),
"milestones": [{
"milestoneId": ObjectId(...),
"pulses": [{
"pulseId": ObjectId(...)
}]
}]
}]
}
Now if you want to add a pulse to a milestone which exists inside a project
db.users.updateOne({
"_id": ObjectId(userId)
}, {
"$push": {
"access.projects.$[i].milestones.$[j].pulses": ObjectId(pulseId)
}
}, {
arrayFilters: [{
"i.projectId": ObjectId(projectId)
}, {
"j.milestoneId": ObjectId(milestoneId)
}]
})
For PyMongo, use arrayFilters like this-
db.users.update_one({
"_id": ObjectId(userId)
}, {
"$push": {
"access.projects.$[i].milestones.$[j].pulses": ObjectId(pulseId)
}
}, array_filters = [{
"i.projectId": ObjectId(projectId)
}, {
"j.milestoneId": ObjectId(milestoneId)
}])
Also,
Each array filter must be a predicate over a document with a single
field name. Each array filter must be used in the update expression,
and each array filter identifier $[] must have a corresponding
array filter. must begin with a lowercase letter and not contain
any special characters. There must not be two array filters with the
same field name.
https://jira.mongodb.org/browse/SERVER-831
The positional operator can be used only once in a query. This is a limitation, there is an open ticket for improvement: https://jira.mongodb.org/browse/SERVER-831
As mentioned; more than one positional elements not supported for now. You may update with mongodb cursor.forEach() method.
db.post
.find({"answers.comments.name": "jeff"})
.forEach(function(post) {
if (post.answers) {
post.answers.forEach(function(answer) {
if (answer.comments) {
answer.comments.forEach(function(comment) {
if (comment.name === "jeff") {
comment.name = "joe";
}
});
}
});
db.post.save(post);
}
});
db.post.update(
{ 'answers.comments.name': 'jeff' },
{ '$set': {
'answers.$[i].comments.$.name': 'joe'
}},
{arrayFilters: [ { "i.comments.name": { $eq: 'jeff' } } ]}
)
check path after answers for get key path right
I have faced the same issue for the as array inside Array update require much performance impact. So, mongo db doest not support it. Redesign your database as shown in the given link below.
https://pythonolyk.wordpress.com/2016/01/17/mongodb-update-nested-array-using-positional-operator/
db.post.update( { 'answers.comments.name': 'jeff' },
{ '$set': {
'answers.$.comments.$.name': 'joe'
}},
{ multi: true }
)
Answer is
db.post.update( { 'answers.comments.name': 'jeff' },
{ '$set': {
'answers.0.comments.1.name': 'joe'
}},
{ multi: true }
)