Consider a mongodb collection running on MongooseJS.
Sample Code:
Person.where('uid').equals(19524121).select('name').exec(function(err, data){
// Here I can get the data correctly in an array.
console.log(JSON.stringify(data));
data[0].name = "try to save me now"; // Select the first item in the array
data[0].save(); // Object #<Promise> has no method 'save'.
}
Error - Cant seem to figure out a way to fix this.
Object #<Promise> has no method 'save';
I am a little confused on why this is happening and I have researched quite a bit and can't seem to find a direct answer for this.
The result of a find is an array of records. You probably meant to loop over those records like this:
Person.find({ uid: /19524121/ }).select('name').exec(function(err, data){
for(var i = 0; i < data.length; i++) {
var myData = new Person(data[i]);
myData.name = "try to save me now";
myData.save(); // It works now!
}
}
Also, from the mongoose homepage, it appears that the function callback prototype is function(err, data), not the other way around, which you corrected above.
Look at this from the homepage:
var fluffy = new Kitten({ name: 'fluffy' });
If data[0] currently has a regular JSON object, we need a line like this to convert to a BSON model object.
var myData = new Person(data[0]);
Related
I've a node.js api in which user sends the required fields as an array to be fetched from the mongodb database. I need to find the data of that fields using Find query. I've written forEach statement to loop through that array and got the array elements. But when I try to get the results by inserting the array elements in the query, it doesn't giving the required results. Could any one please help me in resolving the issue by seeing the code below?
templateLevelGraphData: async function(tid,payload){
let err, templateData, respData = [], test, currentValue;
[err,templateData] = await to(Template.findById(tid));
var templateId = templateData.templateId;
payload.variables.forEach(async data=>{
console.log(data); //data has the array elements like variables=["humidity"]
[err, currentValue] = await to(mongoose.connection.db.collection(templateId).find({},{data:1}).sort({"entryDayTime":-1}).limit(1).toArray());
console.log(currentValue);
});
return "success";
}
The expected output is,
[ { humidity: 36 } ]
But I'm getting only _id like,
[ { _id: 5dce3a2df89ab63ee4d95495 } ]
I think data is not applying in the query. But I'm printing the data in the console where it's giving the correct results by displaying the array elements like, humidity. What I need to do to make it work?
When you are passing {data: 1} you are passing an array where is expecting name of column.
You have to create an object where the keys are going to be the elements of the array and set them to 1.
const projection = data.reduce((a,b) => (a[b]=1, a), {});
[...] .find({}, projection) [...]
Actually I got the solution.
for(let i=0;i<payload.variables.length;i++){
var test = '{"'+ payload.variables[i] +'":1,"_id":0}';
var query = JSON.parse(test);
[err, currentValue] = await to(mongoose.connection.db.collection(templateId).find({"deviceId":deviceId},query).sort({"entryDayTime":-1}).limit(1).toArray());
console.log(currentValue); //It's giving the solution
}
I'm new to NodeJS and I'm trying to learn it a bit better by writing a Discord bot. But I'm having an issue with stringifying an object to JSON. I think it's having an issue with the array I'm setting, but I'm not sure how else I would do this. If I'm not supposed to set an array and using my guildMembers example below, how else should I insert this data into my JSON file?
I've looked through a few examples here on StackOverflow and found this particular article: JSON Stringify Removing Data From Object. However, it's not clear to me given what I'm trying to achieve.
var o = {};
var guildKey = guild.id;
o[guildKey] = [];
o[guildKey]['guildMembers'] = {};
var guildMembers = []
guild.members.forEach(function(guildMember, guildMemberId) {
if (!guildMember.user.bot){
var memberData = {
id: guildMember.id,
data: {
userName: guildMember.user.username,
nickName: guildMember.nickname,
displayName: guildMember.displayName,
joinedAt: guildMember.joinedAt
}
}
guildMembers.push(memberData);
};
});
o[guildKey]['guildMembers'] = guildMembers;
json = JSON.stringify(o);
I am expecting the data to show the guildMembers object with the array under the guildKey object. However, the JSON shows only the guildKey object with an empty array:
{"guildKey":[]}
You make guildKey an array and then try to use it as an object ...
Solution is:
o[guildKey] = {};
Just like in the mentioned post.
It is because you are assigning a key-value pair to an array with
o[guildKey]['guildMembers'] = { }; <= o[guildKey]
When iterating over an array to display the contents, JavaScript does not access non-integer keys. You should store o[guildKey] as an object instead.
i have small problem i have this code:
Messages.findOne({id_user: to}, function (err, toUser) {
//dopisujemy wiadomość w tablicy użytkownika
var messArray = toUser.messagesArray;
//przeszukujemy tablice z wiadomościami aby znaleźć odpowiedniego użytkownika
for(var i=0;i<messArray.length; ++i) {
if(messArray[i].id_converser = who) {
// console.log(messArray[i]);
toUser.messagesArray[i].messages.push({id_converser: who,message: message,date: Date()});
toUser.save(function (err) {
if(err) console.log(err);
console.log('Wiadomość dodana');
})
return;
}
}
}) //end zapisujemy wiadomość w miejscu przeznaczenia
and everything seems fine, in console i have message "wiadomosc dodana", but when i check it in database i not see this added data, why.
Thanks for reply.
In order to push to the array in the actual database you need to use $push or something like $addToSet operator
When you modify any deep property or array property of an object in JavaScript you need to use isModified method in order to tell Mongoose that a property of the object is modified and update it in the database.
http://mongoosejs.com/docs/api.html#document_Document-isModified
So you need to execute it after the push function like that:
toUser.isModified('messagesArray')
I'm trying to get the object id after adding it to the db (using collection.insert)
mongoose.model('Persons').collection.insert(person, function(err, newPerson) {
console.log('lets see you', newPerson);
});
and from the console I'm getting only result: { ok: 1, n: 1 } in stand of the new obj, any ideas how can I rich to the new object ?
thanks!
You can use save() here
var Persons = mongoose.model('Persons');
var personJSON = {
..... // persons schema values you want to insert
};
var person = new Persons(personJSON);
var result = yield person.save();
result variable will contain all the fields you inserted along with _id
I'm about to begin writing a new module for a system I'm developing. We use a MySQL database (so I'm using node-mysql) which contains a customers table.
What I want to achieve is:
Outside of the module I'm looking to do var C = new Customer(1) where 1 is the customer ID.
Now when I want to get something from this customer, I can do C.email or C.first_name which will simply return a value.
I also need to be able to set values back on this customer, C.email = 'example#example.com' or perhaps:
C.set('email', 'example#example.com')
What would be the best pattern to create such a model?
I already have something like this... Not exactly what you demanded but very close to that
I have generalized the core part and here is the code..Hope this will help....
var mysql = require('mysql');
var con = mysql.createConnection({
host:"yourHostName",
user:"yourUserName",
password:"yourPassword"
});
con.query("use databaseName");
function getCustomerDetails(custId){
con.query("select * from customer where custId = "+custId,function(err,result,fields){
if(!err)
return result;
else
console.log(err);
});
}
function updateCustomerDetails(custId,fieldName,fieldValue){
con.query("update customer set "+fieldName+" = "+fieldValue+" where custId = "+custId,function(err,result,fields){
if(!err)
return true;
else
console.log(err);
return false;
});
}
exports.getCustomerDetails = getCustomerDetails;
exports.updateCustomerDetails = updateCustomerDetails;
And then suppose you saved the module as dbAccessModule.js Then you can use the functions like this
var C = require('./dbAccessModule');
result = C.getCustomerDetails(1);
console.log(result.fieldName);
var success = C.updateCustomerDetails(1,'name','sumit');
if(success)
console.log('Table Updated successfully....');
else
// take necessary action according to your application
One thing you need to take care of is that if you are updating any field with string value
then please don't forget to surround the value of fieldValue with single quotes.
If this is not what you asked for then please ignore it....
I recently created two database modules you might be interested in checking out to see if they fit your needs - an ORM: http://bookshelfjs.org and Query Builder: http://knexjs.org
The ORM is based off of the design patterns of Backbone.js
So, you'd be able to do something like this:
// Create the base customer object
var Customer = Bookshelf.Model.extend({
tableName: 'customers'
});
// Create a new customer instance with an id of 1, fetch it, and then
// act on the result model 'customer'.
new Customer({id: 1}).fetch().then(function(customer) {
console.log(customer.get('name'))
customer.set('email', 'email#example.com')
return customer.save();
});
You could also extend the base Customer class to enable a shortened syntax, similar to what you're looking for:
// Create the base customer object, with a static findOne method.
var Customer = Bookshelf.Model.extend({
tableName: 'customers'
}, {
find: function(id) {
return new this({id: id}).fetch();
}
});
Customer.find(1).then(function(C) {
console.log(C.get('name'))
C.set('email', 'email#example.com')
});