I want to make a counter of how many time the server js file has started, for my website using mongodb driver for angular js.
I want to save a varible named counter which has a value of 0 and then increment that value each time that the server is running. my code is below. as you can see my code doesn't acutally update the field in the db. just the varible.
beside that... well.. the whole code I wrote seems like bad practise. I basically have a document with {id:<>,count:0} and I am looping through all the count fields which are greater the -1 (i.e. integers) although I have only got just 1 count field.
isn't there any simple way to persist/get this 1 value from the db?
How can I update the field inside the db itself using something like $inc, in the easiest way possible?
Thanks
MongoClient.connect(url, function(err, db) {
assert.equal(null, err);
if (err) {
console.log(err);
}
else {
console.log("Connected correctly to DB.");
var dbusers =db.collection('users');
var cursor =dbusers.find( { "count": { $gt: -1 } } );
cursor.each(function(err, doc) {
assert.equal(err, null);
if (doc != null) {
doc.count=doc.count+1;
}
}
);
}
db.close();
});
Try this:
MongoClient.connect(url, function(err, db) {
if (err) {
console.log(err);
return db.close();
}
console.log("Connected correctly to DB.");
// update a record in the collection
db.users.update(
// find record with name "MyServer"
{ name: "MyServer" },
// increment it's property called "ran" by 1
{ $inc: { ran: 1 } }
);
return db.close();
});
This should be enough to get you started. It sounds like you're trying to do something like:
get me all the objects in the collection that have a property 'count' greater than -1
increase it's value by 1
save it to the collection.
The step you're missing is step 3. Doing it your way you'd have to do a bulk update. The example I gave you is updating a single record.
here is the documentation for increment. And here is the documentation for bulk updates.
Related
SECOND EDIT
The issue was caused by the MAX_INTEGER_VALUE which is lower then the integer value I was passing. I changed the MySQL table column to TEXT instead of BIGINT and everything is being returned correctly.
Thanks for all the help!
EDIT
So I just realized that the userID variable and the guildID variables are being passed using this line of code.
mysqlModule.userCrewSearch(575783451018526744, 282997056438665217);
However the values that are being supplied to the SQL statement turn the last two digits of the number into '00'. So instead of 575783451018526744 the value being passed into the SQL statement is 575783451018526700.
So why is this value being changed when nothing I am doing in my code is changing these values?
Original Post
I'll keep this short and sweet. I'm trying to run a query using the nodejs MySQL package. I'm not sure where I'm going wrong but whenever I call my function that executes my query, I'm always returned an empty array, unless I hardcode the values into the SQL query.
Heres the code:
// Search for the User's Crew
function userCrewSearch(guildID, userID) {
pool.getConnection(function(err, connection) {
if(err) {
return console.log(err);
}
var sql = "SELECT * FROM `crew-members` WHERE `userID`=? AND `guildID`=?;";
console.log(sql);
connection.query(sql, [guildID, userID], function(err, results) {
connection.release(); // always put connection back in pool after last query
if(err) {
return console.log(err);
}
return console.log(results);
});
});
}
I'm calling this function like so: userCrewSearch(575783451018526744, 282997056438665217);
Both of the values I'm passing are integers. However this is what I get in my console.
However, here is my code with the values hardcoded into the SQL... to which the code then returns the result in the form of a RowDataPacket.
// Search for the User's Crew
function userCrewSearch(guildID, userID) {
pool.getConnection(function(err, connection) {
if(err) {
return console.log(err);
}
var sql = "SELECT * FROM `crew-members` WHERE `userID`=282997056438665217 AND `guildID`=575783451018526744;";
console.log(sql);
connection.query(sql, [guildID, userID], function(err, results) {
connection.release(); // always put connection back in pool after last query
if(err) {
return console.log(err);
}
return console.log(results);
});
});
}
Heres the result.
Bonus Question: How do I handle the RowDataPacket? Can I convert this directly into an object so I can call results.crewID and return just that value?
Same problem i was facing few days ago. I have solved this by converting the parameters into string.
function userCrewSearch(String(guildID), String(userID)) {
// your code here
}
Try adding + before your numeric parameter, it converts into number, it worked for me-
connection.query(sql, [+guildID, +userID], function(err, results) {
for your bonus questions answer, you can directly access the crewID or some other key using,
results[0].crewID
or do something like -
const [ result ] = results;
console.log(result.crewID)
I have a records of 15K in my collection with min 40 fields, I created a table which is generated from records. In this table i have various fileds as shown in image(from Excel sheet).
/client/main.js
Template.GetTable.helpers({
'getTotalData':function(key1,key2){
console.log("-------inside totalData()---------");
const projects1 = Template.instance().distinct1.get();
var filter1= _.map(projects1, col_8 => {
return {col_8};
});
q={};
p={};
console.log(filter1);
console.log(JSON.stringify(q));
//var queryData=test.find(q).fetch();
Meteor.call('getCountData',"all",function(err,count){
if(err)
console.log("Failed to call meteor..!");
else{
console.log(count);
return count;
}
});
},
});
/server/main.js
Meteor.methods({
'getCountData':function(type){
return test.find({"col_17" : " Query->:#####->x","col_8": { $regex: /^CQI?/i}}).count();
},
});
I was just testing for testing and i know how to get the count from DB.
My problem is after all the rendering and the helpers are called the UI will load without any count data. But when i checked in debugger i got the right counts printed using "console.log()" and the UI is not updated.
How can i resolve this issue? or is there any efficient way to solve this?
The UI problem is that you're doing a Meteor calling inside a helper and returning the result of the call to itself, not the helper.
Here's an example of what you're doing and what you SHOULD be doing.
SHOULD NOT:
Template.GetTable.helpers({
'getTotalData':function(key1,key2){
Meteor.call('getCountData',"all",function(err,count){
if(err)
console.log("Failed to call meteor..!");
else {
return count; // Being returned to this function, not helper fuction
}
});
},
});
SHOULD:
var recVar = new ReactiveVar(false);
Template.GetTable.onCreated({
Meteor.call('getCountData',"all",function(err,count){
if(err)
console.log("Failed to call meteor..!");
else {
recVar.set(count);
}
});
});
Template.GetTable.helpers({
'getTotalData':function(key1,key2){
return recVar.get();
},
});
I'm using Node.js with MongoDB, I'm also using Monk for db access. I have the below code :
console.time("start");
collection.findOne({name: "jason"},
function(err, document) {
for(var i = 0; i < document.friends.length; i++) // "friends is an array contains ids of the user's friends"
{
collection.findOne({id: document.friends[i]}, function(err, doc)
{
console.log(doc.name);
});
}
});
console.log("The file was saved!");
console.timeEnd("start");
I have two questions regarding this code :
I see the execution time and "The file was saved!" string first, then I see the names of the friends coming in the console. Why is that? Shouldn't I see the names first then the execution time? Is it because the async nature of Node.js?
Names are printing very slowly in the console, the speed is like one name in two seconds. Why is it so slow? Is there a way to make the process faster?
EDIT:
Is it a good idea to break friends list to smaller pieces and call friends asynchronously? Would it make the process faster?
EDIT 2:
I changed my code to this :
collection.find({ id: { "$in": document.friends}}).then(function(err, doc)
{
console.log(doc.name);
if(err) {
return console.log(err);
}
}
This doesn't give an error, but this doesn't print anything either.
Thanks in advance.
Answer for question 1:
Yes, you are right.
Is it because the async nature of Node.js.
And to prevent that Node.js provides some mechanism for that you can use it otherwise you can do it on your own manually by setting one flag.
Answer for question 2:
you can use $in instead of findOne, it will be ease and fast.
e.g. .find({ "fieldx": { "$in": arr } })
arr :- In this you need to provide whole array.
yes, it's because javascript's async nature.
As you have called db from for loop javascript will not wait for it's response and continue the execution so it will print the file was saved first.
about your ans 2
It's making a dbCall for every friend then it's obvious that it will take some time that's why it's taking 1 or 2 secs for every friend.
console.time("start");
collection.findOne({name: "jason"},
function(err, document) {
for(var i = 0; i < document.friends.length; i++) // "friends is an array contains ids of the user's friends"
{
console.log("InsideforLoop Calling " + i + " friend");
collection.findOne({id: document.friends[i]}, function(err, doc)
{
console.log(doc.name);
});
console.log("Terminating " + i + "-----");
}
});
console.log("The file was saved!");
console.timeEnd("start");
This will make your async and db doubts more clear.
As you will see it will print all console in line.
InsideforLoop Calling 0 friend
Terminating 0 -----
and so on....Like this
console.log(doc.name);
but this will be printed asynchronusly
Added
collection.findOne({name: "jason"},
function(err, document) {
//you can do this
collection.find({id: $in:{document.friends}, function(err, doc)
{
console.log(doc);
});
});
Find All Details in one call
collection.aggregate([
{
$match:{
id :{ "$in" : document.friends},
}
}
]).exec(function ( e, d ) {
console.log( d )
if(!e){
// your code when got data successfully
}else{
// your code when you got the error
}
});
collection.findOne({name: "jason"},
function(err, document) {
if(document != undefined){
collection.find({ id: { "$in": document.friends}}).then(function(err, doc)
{
console.log(doc.name);
if(err) {
return console.log(err);
}
}
}
});
Answer to 1: Yes, it is because node is async. The part where it logs names is executed only when the first findOne returns, whereas the file was saved is executed straight away.
I have a mongoose model that looks like this:
module.exports = mongoose.model('Item', {
text : String,
position: Number
});
And I'm looking to have a Position field that increments on something like the .length of all the documents, for sorting the results of a .find of All:
// get All Items
app.get('/itemsList', function(req, res) {
// use mongoose to get all items in the database
Item.find({
sort : { position: 1 } // sort by Ascending Position
}. function(err, items) {
// if there is an error retrieving, send the error. nothing after res.send(err) will execute
if (err)
res.send(err)
res.json(items); // return all items in JSON format
});
});
Is there a way to auto-fill a number for the Position field with some javascript in node.js?
// create an item
app.post('/api/item', function(req, res) {
// create an item, information comes from AJAX request from Angular
Item.create({
text : req.body.text,
position:
// something using ++items.length
}, function(err, item) {
if (err)
res.send(err);
});
});
Mongoose lets you hook into the save, validate and remove methods and execute code before and after they're executed.
This code can be asynchronous. For example, in your case you could probably do this:
var schema = mongoose.Schema({
text : String,
position: Number
});
schema.pre("validate", function(next) {
var doc = this;
// If 'position' is not filled in, fill it in.
// Not using !position because 0 might be a valid value.
if(typeof position !== "number") {
// Count the number of Items *
mongoose.model("Item").count(function(err, num) {
// If there was an error, pass it to next().
if(err)
return next(err);
// Update the position, then call next();
doc.position = num;
return next();
});
} else {
// There is no need to count, so call next().
next();
}
});
module.exports = mongoose.model('Item', schema);
More here.
Before validation starts, the number of Items is counted. Afterwards, the position is set.
Validation and other pre-validator ** hooks will not commence until the above code is ready.
* I'm using mongoose.model here to fetch the model because the model is not compiled yet (that happens a bit below).
** The documentation shows you how you can make multiple pre-validator hooks execute in parallel. I've chosen not to do this in this example because the code is easier to read and because you might actually need the validators to run sequentially.
In the pre-validation hook, you could place some logic in the else-case. When inserting an Item with an existing position value, you'll want to move every record down. You can do this by doing the following:
Use this.isModified("position") to check if the value was changed since you last saved. You might also need doc.isNew().
Check if there is an existing document with the same position. Something like Item.where({_id: {$ne: this._id}, position: this.position}).count()
If there is, execute: Item.update({position: {$gte: this.position}}, {position: {$inc: 1}}, {multi: 1})
Then call next() to save your doc.
The above should work. It will leave gaps when you remove documents however.
Also, look into indexes. You'll want to add one on the position field. Perhaps even a unique index.
Per #RikkusRukkus's steps for moving records down, here's logic for the else-case (to be tested)
// load mongoose since we need it to define a schema and model
var mongoose = require('mongoose');
var ItemSchema = mongoose.Schema({
text : String,
position: Number
});
// before validation starts, the number of Items is counted..afterwards, the position is set
ItemSchema.pre("validate", function(next) {
var doc = this;
// if 'position' is not filled in, fill it in..not using !position because 0 might be a valid value
if(typeof position !== "number") {
// count the number of Items *
// use mongoose.model to fetch the model because the model is not compiled yet
mongoose.model("Item").count(function(err, num) {
// if there was an error, pass it to next()
if(err)
return next(err);
// set the position, then call next();
doc.position = num;
return next();
});
} else if(this.isModified("position") || this.isNew()) {
// check if there is an existing document with the same position
// use mongoose.model to fetch the model because the model is not compiled yet
mongoose.model("Item").where({_id: {$ne: this._id}, position: this.position}).count( function (err, count) {
// if there was an error, pass it to next()
if(err)
return next(err);
// if there is a doc with the same position, execute an update to move down all the $gte docs
if(count > 0) {
// use mongoose.model to fetch the model because the model is not compiled yet
mongoose.model("Item").update({position: {$gte: this.position}}, {position: {$inc: 1}}, {multi: 1}, function(err, numAffected) {
// Call next() (with or without an error)
next(err);
});
} else {
// there are no docs that need to move down, so call next()
next();
}
});
} else {
// there is no need to count or update positions, so call next()
next();
}
});
module.exports = mongoose.model('Item', ItemSchema);
Let me explain my problem first.
I am trying to get the ID from URL and use it to find a record in the database(MongoDB). The following code I have in NodeJS Express App.
app.post('/dashboard/profile/update/:id',function(req,res){
var to_update=req.params.id;
var firstName=req.body.fname;
obj_to_search={_id:to_update};
db.open(function(err, dbs) {
if(!err) {
dbs.collection('project',function(err, collection) {
//update
collection.findOne(obj_to_search, function(err, result) {
if (err) {
throw err;
} else {
res.send(result);
}
dbs.close();
});
});
}
});
});
I am getting the record if I hard code the ID to 1. But I am not getting the record by this way. However I have checked using console.log the ID i am getting through URL is also 1.
Convert strings to integers
If a variable is in the url - it's a string. If you're wanting to query the database with a number, you'll need to cast it to a number for use in the query:
obj_to_search={_id: parseInt(to_update,10)};