What I want to do:
Whenever I add a new item to the collection (in my case a game), it will have a incremented "index"-like value (in my case I'm naming it index too).
My games collection should looks like:
[
{ "index":0, ... data }
{ "index":1, ... data }
{ "index":2, ... data }
]
The term is so hard to search. I always end up with:
$inc for update. Not this, I want to have incremented number on create.
Schema.index does look like what I want, but somehow it doesn't work at all:
const gameModel = new Schema({
index: {
type: Number,
default: 0
},
players: [{
name: String,
score: Number
}]
}, {
timestamps: {
createdAt: 'date'
}
});
gameModel.index({
index: 1
});
With this I always get index: 0. If I turn off default no index is created.
What do I do now? (I would prefer to keep the _id intact)
You can use a npm package named mongoose-auto-increment which provides this functionality. It is also very easy and well documented
Related
What I was hoping to do was store an array of objects using RedisJSON very simply and then query that array.
I have something similar to this:
const data = [
{
_id: '63e7d1d85ad7e2f69df8ed6e',
artist: {
genre: 'rock',
},
},
{
_id: '63e7d1d85ad7e2f69df8ed6f',
artist: {
genre: 'metal',
},
},
{
_id: '63e7d1d85ad7e2f69df8ed6g',
artist: {
genre: 'rock',
},
},
]
then I can easily store and retrieve this:
await redisClient.json.set(cacheKey, '$', data)
await redisClient.json.get(cacheKey)
works great. but now I want to also query this data, I've tried creating an index as below:
await redisClient.ft.create(
`idx:gigs`,
{
'$.[0].artist.genre': {
type: SchemaFieldTypes.TEXT,
AS: 'genre',
},
},
{
ON: 'JSON',
PREFIX: 'GIGS',
}
)
and when I try and search this index what I expect is it to return the 2 documents with the correct search filter, but instead it always returns the entire array:
const searchResult = await redisClient.ft.search(`idx:gigs`, '#genre:(rock)')
produces:
{
total: 1,
documents: [
{ id: 'cacheKey', value: [Array] }
]
}
I can't quite work out at which level I'm getting this wrong, but any help would be greatly appreciated.
Is it possible to store an array of objects and then search the nested objects for nested values with RedisJSON?
The Search capability in Redis stack treats each key containing a JSON document as a separate search index entry. I think what you are doing is perhaps storing your whole array of documents in a single Redis key, which means any matches will return the document at that key which contains all of your data.
I would suggest that you store each object in your data array as its own key in Redis. Make sure that these will be indexed by using the GIGS prefix in the key name, for example GIGS:63e7d1d85ad7e2f69df8ed6e and GIGS:63e7d1d85ad7e2f69df8ed6f.
You'd want to change your index definition to account for each document being an object too so it would look something like this:
await redisClient.ft.create(
`idx:gigs`,
{
'$.artist.genre': {
type: SchemaFieldTypes.TEXT,
AS: 'genre',
},
},
{
ON: 'JSON',
PREFIX: 'GIGS:',
}
)
Note I also updated your PREFIX to be GIGS: not GIGS - this isn't strictly necessary, but does stop your index from accidentally looking at other keys in Redis whose name begins GIGS<whatever other characters>.
Good morning/afternoon.
I'm trying to sort out documents based on multiple array properties to make a "Ranking" system.
The user Schema that i want to sort:
const UserSchema = new mongoose.Schema(
{
// ... Rest of the code
modules: {
party: Array,
bank: Array,
// ... Rest of the code
},
{ strict: false }
)
Which every new 'partner' added to the user, pushes This to the modules.bank (or party):
{
_id: "some_randomgenerated_id",
id: "id of the monster on the database",
level: Number,
exp: Number,
stats: {
attack: Number
defense: Number,
additional: {
attack: Number,
defense: Number
}
}
I want to sort the Users based on each partner's streght combined, like partner[0].stats.attack + .defense + (additional stats) and so on...
I Tried using aggregate, but haven't got too far with it.
I want to create a String + number every time a value is inserted on database (the number must be autoincrement).
Is it possible to do in Schema? Or do I need to do that before the value's inserted on database?
'question' -> String followed by an autoincrement number
var random = [{
question: 'question1'
},{
question: 'question2'
},{
question: 'question3'
},{
question: 'question4'
}];
const RandomSchema = new Schema({
question: {
type: String,
unique: true
}
})
Autoincrement fields in Mongodb, don't work exactly the same way that they do in an RDBMS. There is a lot more overhead involved. Never the less, creating an auto field is a solved problem. There is also a third party mongoose-autoincrement package that make it a lot easier.
Extending, from that. Your problem is a solved problem too. Because
the string part will always be the same
Simply use string concatenation to prepend 'question' to the auto increment field at display time.
Here is what I implemented with one of the approaches #e4c5 pointed out, without the use of a third-party package.
Define add.js as below:
db.counters.insert(
{
_id: "itemid",
seq: 0
}
)
function getNextSequence(id) {
var ret = db.counters.findAndModify(
{
query: { _id: id },
update: { $inc: { seq: 1 } },
new: true
}
);
return ret.seq;
}
db.randoms.insert(
{
question: "question"+getNextSequence("itemid"),
}
)
db.randoms.insert(
{
question: "question"+getNextSequence("itemid"),
}
)
After starting a mongod instance, do mongo < add.js.
I am using mongoose to perform CRUD operation on MongoDB. This is how my schema looks.
var EmployeeSchema = new Schema({
name: String,
description: {
type: String,
default: 'No description'
},
departments: []
});
Each employee can belong to multiple department. Departments array will look like [1,2,3]. In this case departments.length = 3. If the employee does not belong to any department, the departments.length will be equal to 0.
I need to find all employee where EmployeeSchema.departments.length > 0 & if query return more than 10 records, I need to get only employees having maximum no of departments.
Is it possible to use Mongoose.find() to get the desired result?
Presuming your model is called Employee:
Employee.find({ "departments.0": { "$exists": true } },function(err,docs) {
})
As $exists asks for the 0 index of an array which means it has something in it.
The same applies to a maximum number:
Employee.find({ "departments.9": { "$exists": true } },function(err,docs) {
})
So that needs to have at least 10 entries in the array to match.
Really though you should record the length of the array and update with $inc every time something is added. Then you can do:
Employee.find({ "departmentsLength": { "$gt": 0 } },function(err,docs) {
})
On the "departmentsLength" property you store. That property can be indexed, which makes it much more efficient.
By some reason, selected answer doesn't work as for now. There is the $size operator.
Usage:
collection.find({ field: { $size: 1 } });
Will look for arrays with length 1.
use can using $where like this:
await EmployeeSchema.find( {$where:'this.departments.length>0'} )
If anyone is looking for array length is greater than 1, you can do like below,
db.collection.find({ "arrayField.1" : { $exists: true }})
The above query will check if the array field has value at the first index, it means it has more than 1 items in the array. Note: Array index start from 0.
I have the following schema:
var sampleSchema = new Schema({
name: String,
dates: [{
date: Date,
duration: Number
}]
});
I'd need to filters the records according to the following rule: if one of dates is later than a given date date_begin, keep the record, otherwise, don't.
I have the impression that $gte or $lte are the function I need, but I can't find a way to use them correctly. I tried
sampleSchema.find({date_begin: {$gte: 'date'}});
or some variants of that, but I can't seem to be able to make it work. Anyone has an idea of how I am supposed to do this?
To do querying on elements inside arrays, $elemMatch is used :
SampleModel.find( { dates : { $elemMatch: { date : { $gte: 'DATE_VALUE' } } } } )
If you're using a single query condition, you can directly filter:
SampleModel.find( { 'dates.date': { $gte: 'DATE_VALUE' } } )