I have an database full of objects that contain information, as well as other arrays of objects. I would like to change the inner arrays to only be arrays with each index as an ObjectId type with their respective ObjectId
I am using the mongoose populate function to retrieve this information later in the program. So only the ObjectId is needed for the reference.
job {
_id: 1,
name: "name",
parts: [
{ _id: ObjectId("5c790ce7d3dc8d00ccc2688c"), name: "name"},
{ _id: ObjectId("5c790ce7d3dc8d00ccc2688b"), name: "name"},
{ _id: ObjectId("5c790ce7d3dc8d00ccc2688a"), name: "name"},
]
}
Desired Result
job {
_id: 1,
name: "name",
parts: [
ObjectId("5c790ce7d3dc8d00ccc2688c"),
ObjectId("5c790ce7d3dc8d00ccc2688b"),
ObjectId("5c790ce7d3dc8d00ccc2688a")
]
}
I tried a few mongoDB queries from the command line but none of them are quite giving the result I need. This one has no errors, but it doesn't seem to change anything.
db.jobs.update(
{},
{
$set: {"parts.$[element]": "element._id"}
},
{
multi: true,
arrayFilters: [{ "element": {} }]
}
)
I'm not sure if this is possible or not using only the mongo shell.
Mongo v4.2 introduced pipelined updates this allows the use of aggregation operators within the update and more importantly updating a document using it's own values. which is what you want to achieve.
db.jobs.updateMany(
{},
[
{
'$set': {
'parts': {
'$map': {
'input': '$parts',
'as': 'part',
'in': '$$part._id'
}
}
}
}
]);
Unfortunately this is not possible for earlier Mongo versions. Specifically $arrayFilters allows you to filter an array but again prior to the new update syntax accessing own values within the update is not possible.
You'll have to iterate over all documents and do the update one by one in code.
As #Tom Slabbaert mentioned in the other answer you will have to use updates with aggregation pipelines available from v4.2 if you want to update the documents in bulk in one operation.
As an alternative to using $map, if you want only a single value at the top level and the value is accessible using the dot notation. You can simply use $set with the dot notation.
db.jobs.updateMany({}, [{
$set: { parts: "$parts._id" }
}])
Related
This issue is a bit tricky to describe so bear with me and please ask questions if I am missing anything...
Say you have a json object that defines a list of features, each feature has a the same three properties but has a property that has an entirely different structure. For example:
{
features: [
{
id: "feature-a",
enabled: true,
configurationData: {
featureAConfigPropertyA: {
somePrperty: "whatever",
anotherProperty: true
},
featureAConfigPropertyB: "some string"
}
},
{
id: "feature-b",
enabled: true,
configurationData: {
featureBConfigArrayPropertyA: ["some string"],
featureBConfigPropertyB: [
{
"id": "some string",
"name": "some string",
"description": "some string",
"enabled": true
}
]
}
}
]
}
The actual structure of each feature is irrelevant. I am just trying to express this via json schema whereby the structure of configurationData for each feature is dependent on or dictated by the feature id value of its parent.
EDIT: I guess technically it doesnt need to be dependent on so long as either structure of configurationData is valid schema for that property on the feature schema itself. Also, the types in configurationData arent arbitrary, they would always be one of the two types for a given feature in this example.
This however needs to be structured in a way that can be expressed via Formly as I am using this to generate forms. In this case it would be an array of ObjectFieldTypes, one for feature a and one for feature b, which would enumerate the three properties and provide Input field types, until it got to configurationData at which point it would use an ObjectFieldType again, which would now be different for each field type.
The issue here is that 1) I'm not sure how to express this in json schema and 2) I can't use things like patternProperties with formly because the properties have to be explicitly defined in the json schema in order for formly to render the field types for each property. Although patternProperties would technically be valid schema in this case, if the schema doesn't define those properties, then the model in the valueChanges observable on the FormGroup just excludes them entirely. So I would end up with:
{
features:[
{
id: "feature-a",
enabled: true,
configurationData: { }
},
{
id: "feature-b",
enabled: true,
configurationData: { }
}
]
}
I have tried the if then else construct, but I cant tell if the schema is wrong or if formly just doesn't support this. I made a stack blitz for this below:
https://stackblitz.com/edit/angular-g45ydm?file=src%2Fassets%2Fjson-schema%2Fif_then.json
I am using library for my electron app called electron-store
It has a feature to validate config data.
I want the value to be stored in config file is a string. I can achive that by define schema like this:
const schema = {
1: {
type: 'string',
},
2: {
type: 'string',
},
3: {
type: 'string',
},
4: {
type: 'string',
},
};
const store = new Store({schema});
The data in my config.json file:
{
"1": "lorem epsum...",
"2": "epsum lorem...",
"3": "epsum epsum...",
"4": "lorem lorem..."
}
The problem is I have hundreds line of datas like that, so it would be great if I could just define:
const schema = {
[any_key_name]: {
type: 'string',
},
};
I think I can use "patternProperties" when defining schema to achive it but I don't know how. help me please.
It looks like you cannot do this with electron-store as you want.
The docs say the following:
You should define your schema as an object where each key is the name
of your data's property and each value is a JSON schema used to
validate that property.
https://github.com/sindresorhus/electron-store#schema
This means that the root "schema" is not a JSON Schema. Only the value of each KEY is a JSON Schema.
If you want to use dynamic names, I think you would need to nest it under a specific key name, and validate that as a single object, although this is probably not what you really want to do with a store.
Sorry, I'm not familiar with electron-store specifically.
If you COULD provide a full JSON Schema for the whole store...
You can use patternProperties.
If you don't need to check the key follows any specific regex, you can use additionalProperties, which would then cover all properties not checked by properties (if present).
LEt's look at the specification: https://datatracker.ietf.org/doc/html/draft-handrews-json-schema-validation-01#section-6.5.6
The value of "additionalProperties" MUST be a valid JSON Schema.
This keyword determines how child instances validate for objects,
and does not directly validate the immediate instance itself.
Validation with "additionalProperties" applies only to the child
values of instance names that do not match any names in "properties",
and do not match any regular expression in "patternProperties".
As a pure JSON Schema, you'd be looking at...
{
"additionalProperties": {
"type": "string"
}
}
You can easily test this using https://jsonschema.dev (link has an example for you)
react-redux-firebase supports replacing ids with the corresponding value in a lookup object – like a join – through a config object called populates (and later using a convenient mapping function inside mapStateToProps).
Unfortunately, the documentation of react-redux-firebase is rather rudimentary in this area (and in others)...
Can someone tell me, whether it's possible to populate a list of ids?
For example:
// from:
{ friends: [1, 27, 42] }
// to:
{ friends: [
{ id: 1, name: 'Charlie' },
{ id: 27, name: 'Parker' },
{ id: 42, name: 'Brown' },
] }
Testing version 3.0.0, it seems that populating a list works exactly the same as replacing a single field. Instead of receiving back an object you will receive an array of replaced objects.
Let's say this is the table inside my collection:
{
"_id" : ObjectId("557cf6bbd8efe38c627bffdf"),
"name" : "John Doe",
"rating" : 9,
"newF" : [
"milk",
"Eggs",
"Beans",
"Cream"
]
}
Once a user types in some input, it is sent to my node server, and my node server then adds that item to the list "newF", which is then sent back to my MongoDB and saved.
I'm trying to use update, which can successfully change the values inside of this table, but I'm not sure how to add new items onto that list. I did it with $push inside the MongoDB shell, but not sure how to do it on node.
Here's a snippet of my code:
db.collection('connlist').update({ _id: new ObjectId("e57cf6bb28efe38c6a7bf6df")}, { name: "JohnDoe", rating: 9, newF: ["Milk, Eggs", "Beans"] }, function(err,doc){
console.log(doc);
});
Well the syntax for adding new items is just the same as in the shell:
// make sure you actually imported "ObjectID"
var ObjectId = require('mongodb').ObjectID;
db.collection('conlist').update(
{ "_id": new ObjectId("e57cf6bb28efe38c6a7bf6df") },
{ "$push": { "newF": { "$each": [ "cream", "butter" ] } } },
function(err,numAffected) {
// do something in the callback
}
)
Or perhaps use .findOneAndUpdate() if you want to return the modified document instead of just making the alteration.
Of course use $push and possibly with $each which allows multiple array elements to be added when adding to an array. If you want "unique" items then use $addToSet where your operation allows.
And generally speaking for other items you should use $set or other operators in the update portion of your document. Without these operators you are just "replacing" the document content with whatever structure you place in the "update" portion of your statement.
I am new to sails.js and mongodb. I found something strange. When i use rest api to update the record in mongodb, after record updated, the json format changed.
For example. Originally I have a record like this:
{
creator: "John",
taskname: "test",
id: "53281a5d709602dc17b000cd"
}
After clicking http://127.xxx:1337/testtask/update/53281a5d709602dc17b000cd?creator=default%20creator, following json returned.
The json field is sorted in alphabetic order.
How can i keep the origin format of the json file? Is it a bug? Is there any workaround?
{
createdAt: "2014-03-18T10:05:17.052Z",
creator: "default creator",
taskname: "test",
updatedAt: "2014-03-18T10:08:53.067Z",
id: "53281a5d709602dc17b000cd"
}
Thanks.
The problem is fields in JSON objects don't have any concept of order. A JSON object is a dictionary, or in other words just some key/value pairs. This means that this JSON:
{ "a" : "some string", "b" : "other string" }
is logically equivalent to this JSON:
{ "b" : "other string", "a" : "some string" }
If you want to preserve ordering in your JSON data there are other ways to do it. For example JSON arrays do preserve order so something like this would work:
[ { "a" : "some string" }, { "b" : "other string" } ]
Internally MongoDB may actually preserve the ordering, but that's an implementation detail and you can't depend on it.
More detail on what Mongo is doing here.
Much like the "other" framework that inspired this, there is some automatic time-stamp generation happening in your models when things are updated or created. You wouldn't be the first. Ruby people have been trapped by this for years.
There are options you can define on your collection objects to remove these fields. This comes from the Waterline documentation, which should be the manager in use.
So in addition to attributes:
autoCreatedAt: false,
autoUpdatedAt: false,
attributes: {
// normal things here
},
Of course you will need to remove any of these properties that have been created in your documents manually. See the $unset operator for doing this