I have a mongoose model: (With a field that has a default)
var MySchema= new mongoose.Schema({
name: {
type: String,
required: true
},
isClever: {
type: Boolean,
default: false
}
});
I can save a model of this type by just saving a name and in mongoDB, only name can be seen in the document (and not isClever field). That's fine because defaults happen at the mongoose level. (?)
The problem I am having then is, when trying to retrieve only people called john and isClever = false:
MySchema.find({
'name' : 'john',
'isClever': false
}).exec( function(err, person) {
// person is always null
});
It always returns null. Is this something related to how defaults work with mongoose? We can't match on a defaulted value?
According to Mongoose docs, default values are applied when the document skeleton is constructed.
When you execute a find query, it is passed to Mongo when no document is constructed yet. Mongo is not aware about defaults, so since there are no documents where isClever is explicitly true, that results in empty output.
To get your example working, it should be:
MySchema.find({
'name' : 'john',
'isClever': {
$ne: true
}
})
Related
I'm trying to query an object that's inside an item which is inside a mongoose model, when I'm trying to find that object with the find() method or _.find() method, I can't get access to the object for some reason and when I console.log() it, it gives me undefined or when I use array.filter() it gives me an empty array, which means the object that I'm trying to access does not meet the criteria that I give it in the lodash find method, but then when I look at my database I see that the object does actually have the properties to meet the criteria. So I don't know what I'm doing wrong, here's my code: as you can see I'm trying to get the information of the item that the user clicked on and want to see:
router.get("/:category/:itemId", (req, res) => {
console.log(req.params.itemId);
//gives the item id that the user clicked on
console.log(req.params.category);
//gives the name of category so I can find items inside it
Category.findOne({ name: req.params.category }, (err, category) => {
const items = category.items; //the array of items
console.log(items); //gives an array back
const item = _.find(items, { _id: req.params.itemId });
console.log(item); //gives the value of 'undefined' for whatever reason
});
});
The category Schema:
const catSchema = new mongoose.Schema({
name: {
type: String,
default: "Unlisted",
},
items: [
{
name: String,
price: Number,
description: String,
img: String,
dateAdded: Date,
lastUpdated: Date,
},
],
dateCreated: Date,
lastUpdate: Date,
});
well the answer is a little bit obvious, you are using MongoDB and in Mongo you have "_ID" you can use that "_ID" only with Mongoose! so you just have to remove the underscore and that is it! do it like this const item = _.find(items, { id: req.params.itemId });
hope you are doing better.
When I look at your Schema I see that the item field is an array of objects which doesn't have an _id inside so when you create a new instance of catShema it just generates an _id field for the new instance but not for each item inside the items array, just also enter the id of the item in question because according to my understanding, you must also have a model called items in your database
When you save these records in your database, you will generate an element with this structure
{
_id: String, // auto generated
name: String,
items: [ {"name1", "price1", "description1", "imgUrl1", "dateAdded1", "lastUpdated1"},{"name2", "price2", "description2", "imgUrl2", "dateAdded1", "lastUpdated2"}, ...],
dateCreated: Date,
lastUpdate: Date
}
Note : the code provided at the top is only an illustration of the object which will be registered in the database and not a valid code
Here you can notice that there is not a field called _id in the object sent inside the database.
My suggestion to solve this issue is
To create an additional field inside the items array called _id like :
{
...,
items: [
{
_id: {
type: String,
unique : true,
required: true // to make sure you will always have it when you create a new instance
},
...
... // the rest of fields of items
},
...
Now when you create a new instance make sure in the object you enter in the database the _id is recorded when you call the catInstance.save() so inside the catInstance object you have to add the current Id of the element to be able to filter using this field.
Hope my answer helped, if you have any additional questions, please let me know
Happy coding ...
I'm trying to add a user to my users collection and keep getting a duplicate null key value error.
My Users model used to look like this like this:
const mongoose = require("mongoose");
const UserSchema = new mongoose.Schema({
name: {
type: String,
required: true
},
email: {
type: String,
required: true,
unique: true
},
profilePictures: [{
link: {
type: String
}
rank: {
type: Number,
unique: true
}
}],
});
module.exports = User = mongoose.model("users", UserSchema);
Before I changed the pictures field to
...
pictures = []
...
I believe because I saved users under the former schema, it has saved somewhere the model of the object in the pictures array (they would be given an ObjectId when I saved something to that array).
Even though I have changed the field to
pictures = []
I still get this error
E11000 duplicate key error collection: testDB.users index: profilePictures.rank_1 dup key: { profilePictures.rank: null }
When neither profilePictures nor rank fields even exist anymore.
I imagine I can probably just delete the users collection and start again but I want to know if there is a better way to handle this error? Suppose I had 100 users in the users collection – I wouldn't be able to just delete them all.
Thanks!
you added unique property true in your model to profilePictures.rank. on first request it is saving null as you may be not providing rank in your query.
second time it is again trying to save null but it is also marked unique so it is throwing exception.
solution:
remove unique flag from profilePictures.rank
provide unique value for profilePictures.rank
I was wondering if there is way to force a unique collection entry but only if entry is not null.
e
Sample schema:
var UsersSchema = new Schema({
name : {type: String, trim: true, index: true, required: true},
email : {type: String, trim: true, index: true, unique: true}
});
'email' in this case is not required but if 'email' is saved I want to make sure that this entry is unique (on a database level).
Empty entries seem to get the value 'null' so every entry wih no email crashes with the 'unique' option (if there is a different user with no email).
Right now I'm solving it on an application level, but would love to save that db query.
thx
As of MongoDB v1.8+ you can get the desired behavior of ensuring unique values but allowing multiple docs without the field by setting the sparse option to true when defining the index. As in:
email : {type: String, trim: true, index: true, unique: true, sparse: true}
Or in the shell:
db.users.ensureIndex({email: 1}, {unique: true, sparse: true});
Note that a unique, sparse index still does not allow multiple docs with an email field with a value of null, only multiple docs without an email field.
See http://docs.mongodb.org/manual/core/index-sparse/
tl;dr
Yes, it is possible to have multiple documents with a field set to null or not defined, while enforcing unique "actual" values.
requirements:
MongoDB v3.2+.
Knowing your concrete value type(s) in advance (e.g, always a string or object when not null).
If you're not interested in the details, feel free to skip to the implementation section.
longer version
To supplement #Nolan's answer, starting with MongoDB v3.2 you can use a partial unique index with a filter expression.
The partial filter expression has limitations. It can only include the following:
equality expressions (i.e. field: value or using the $eq operator),
$exists: true expression,
$gt, $gte, $lt, $lte expressions,
$type expressions,
$and operator at the top-level only
This means that the trivial expression {"yourField"{$ne: null}} cannot be used.
However, assuming that your field always uses the same type, you can use a $type expression.
{ field: { $type: <BSON type number> | <String alias> } }
MongoDB v3.6 added support for specifying multiple possible types, which can be passed as an array:
{ field: { $type: [ <BSON type1> , <BSON type2>, ... ] } }
which means that it allows the value to be of any of a number of multiple types when not null.
Therefore, if we want to allow the email field in the example below to accept either string or, say, binary data values, an appropriate $type expression would be:
{email: {$type: ["string", "binData"]}}
implementation
mongoose
You can specify it in a mongoose schema:
const UsersSchema = new Schema({
name: {type: String, trim: true, index: true, required: true},
email: {
type: String, trim: true, index: {
unique: true,
partialFilterExpression: {email: {$type: "string"}}
}
}
});
or directly add it to the collection (which uses the native node.js driver):
User.collection.createIndex("email", {
unique: true,
partialFilterExpression: {
"email": {
$type: "string"
}
}
});
native mongodb driver
using collection.createIndex
db.collection('users').createIndex({
"email": 1
}, {
unique: true,
partialFilterExpression: {
"email": {
$type: "string"
}
}
},
function (err, results) {
// ...
}
);
mongodb shell
using db.collection.createIndex:
db.users.createIndex({
"email": 1
}, {
unique: true,
partialFilterExpression: {
"email": {$type: "string"}
}
})
This will allow inserting multiple records with a null email, or without an email field at all, but not with the same email string.
Just a quick update to those researching this topic.
The selected answer will work, but you might want to consider using partial indexes instead.
Changed in version 3.2: Starting in MongoDB 3.2, MongoDB provides the
option to create partial indexes. Partial indexes offer a superset of
the functionality of sparse indexes. If you are using MongoDB 3.2 or
later, partial indexes should be preferred over sparse indexes.
More doco on partial indexes: https://docs.mongodb.com/manual/core/index-partial/
Actually, only first document where "email" as field does not exist will get save successfully. Subsequent saves where "email" is not present will fail while giving error ( see code snippet below). For the reason look at MongoDB official documentation with respect to Unique Indexes and Missing Keys here at http://www.mongodb.org/display/DOCS/Indexes#Indexes-UniqueIndexes.
// NOTE: Code to executed in mongo console.
db.things.ensureIndex({firstname: 1}, {unique: true});
db.things.save({lastname: "Smith"});
// Next operation will fail because of the unique index on firstname.
db.things.save({lastname: "Jones"});
By definition unique index can only allow one value to be stored only once. If you consider null as one such value it can only be inserted once! You are correct in your approach by ensuring and validating it at application level. That is how it can be done.
You may also like to read this http://www.mongodb.org/display/DOCS/Querying+and+nulls
I have at production a NodeJS application running using MongoDB and Mongoose, which inside has a Mongoose Schema like:
var Product = new Schema({
"name": { type: String, required: true }
, "description": { type: String }
});
Now, as a new requirement I'm adding a new property to the Schema at my local, like this:
var Product = new Schema({
"name": { type: String, required: true }
, "description": { type: String }
, "isPublic": { type: Boolean, default: true }
});
When I restart my NodeJS process, I was expecting an update to all of my current documents (products), so now every document have a property isPublic which value is true.
What happened is no document has that new property and if I do a someProduct.Save({ isPublic: true }) it gets added.
Question: is there a way to accomplish that?,
I know I can do a $set from command line with mongo client, but I want to know if there is a way where Mongoose will add the missing property after the Schema changed on a process restart.
What happened is no document has that new property and if I do a someProduct.Save({ isPublic: true }) it gets added.
That's because the mongoose default attribute works just for new documents. There're two workarounds:
Write your code to treat documents without the isPublic property as true;
Or, as you've mentioned above, set the property manually through mongodb console.
Your best bet is to use MongoSH. Adding a new property to a Mongoose Schema will never update existing documents unless the programmer does it.
Use the updateMany command in the Mongo Shell (MongoSH):
// Get all documents in the collection, and set the field to a value
db.users.updateMany( {} ,
{ $set: {"newlyCreatedField": "defaultValue"} }
);
I have the following model for users:
var UserSchema = new mongoose.Schema({
name: String,
dob: Date,
sex: String,
photo: String,
email: {type: String, index: {unique: true, required: true}},
created: {type: Date, default: Date.now}
});
var User = mongoose.model('Users', UserSchema);
As you can see the 'created' field takes a default value of the current date so that it is automatically set when a new user is created.
I use the following query when user details are posted:
User.findOneAndUpdate({email: user.email}, user, {upsert: true}, function (err, user) {
if (err) {
return callback (err);
} else {
callback(null, user);
}
});
The purpose of using findOneAndUpdate with upsert: true is to either return an existing profile, or create a new one. It also updates any fields based on the data posted.
However, the created field gets updated with the current date each time, even though the created field is not posted. How can I make sure that this field is set only once?
EDIT
An example object from the database:
{
"_id" : ObjectId("54620b38b431d48bce7cab81"),
"email" : "someone#google.com",
"__v" : 0,
"name" : "somone",
"sex" : "male"
}
It turns out that the created field is not being set even while creating a new object using upsert. Mongoose just returns the current date based on the schema even though it does not exist in the document.
So, the question now becomes: How do I make sure that using upsert creates the default value for a field not supplied in the arguments?
For adding defaults to your document if it was created with findOneAndUpdate (it didn't exist before the query) and you did not provide the field in the update you should use setDefaultsOnInsert.
When upsert and setDefaultsOnInsert are both true, the defaults will be set if the record is not found and a new one is created.
This skips the workflow of having to check if the record exists and if not then creating a new one with 'save' just to make sure defaults are set.
I have had the same issue (record created with findOneAndUpdate with upsert: true) and the default value for a field was not added to the record, even though it was in the schema.
This is only in regards to adding defaults when using findOneAndUpdate to create documents, not for skipping the update of the 'created' field.
e.g.
User.findOneAndUpdate({email: user.email}, user, {upsert: true, setDefaultsOnInsert:true}, ...)
findOneAndUpdate simply sends a MongoDB findAndModify request (see findOneAndUpdate). What this means is that it skips all the mongoose magic involved with the schema setters, getters, defaults, etc. Validation is only run on create/save so the way around this is to do a .findOne(), check existence/create a new one, and then .save().
see this issue for more discussion
EDIT:
In regards to the first question about changing the date each time, you could change the schema a bit. Get rid of the default value, and instead add this after declaring the schema:
UserSchema.pre("save", function (next) {
if (!this.created) {
this.created = new Date();
}
next();
});
That will only create a date if the created: value is not present, and should prevent it from changing the creation date each time (when using .save()).
see Mongoose middleware