I'm getting below error while fetching records (apx 50 rows) from my sql database. My application is developed in nodejs with express.
var common = require(__base + 'routes/common.js');
var dbhelper = require(__base + 'routes/dbhelper.js');
exports.GetStates = function (callback) {
dbhelper.pool.getConnection(function (err, connection) {
// Use the connection
connection.query('CALL GetStates()',
function (err, res) {
connection.release();
if (err) {
common.ActionOutput.Status = common.ActionStatus.Error;
common.ActionOutput.Message = 'System Error: ' + err.message;
} else {
common.ActionOutput.Status = common.ActionStatus.Success;
common.ActionOutput.Result = res[0][0];
}
return callback(JSON.stringify(common.ActionOutput));
});
});
};
dbhelper.js is
// Database connection
var mysql = require('mysql');
var pool = mysql.createPool({
connectionLimit: 10,
host: 'my ip',
user: 'user',
password: 'pass',,
database: 'ssdsdas'
});
exports.pool = pool;
I ran into the same error message but the causes of our issues might be different. Ultimately, the cause of my issue is that the column names in my stored procedure did not have back ticks (`) resulting in them being treated as variables.
Adding back ticks in my stored procedure body for column names fixed it.
Related
This happens pretty frequently (once a week for about 30-40 minutes), where all of a sudden my database mentions max connections when I try to connect via heidisql, and any apis calls respond with the following error:
Cannot read property 'release' of undefined
I am calling .release() after every query in mysql. Is there something I am missing, am I suppose to call .end as well? I am using nodejs with mysql.
Here is the way I wrap every query and the pool code:
var mysql = require('mysql');
var mysql_pool = mysql.createPool({
connectionLimit: config.mysql.limit,
host: config.mysql.host,
user: config.mysql.user,
password: config.mysql.pw,
database: config.mysql.db //,
// debug: true
});
var qSelect = "SELECT id FROM Users";
var qValues = [];
var qCall = mysql.format(qSelect, qValues);
mysql_pool.getConnection(function(err_pool, connection) {
if (err_pool) {
connection.release();
console.log(' Error getting mysql_pool connection: ' + err_pool);
throw err_pool;
}
connection.query(qCall, function(err, userFound, fields) {
connection.release();
if (err) {
console.log("get user : " + err);
} else {
//some code here
}
});
Can someone please advise, appreciate it.
You should remove first connection.release() used in if loop
if (err_pool) {
console.log(' Error getting mysql_pool connection: ' + err_pool);
throw err_pool;
}
I need display data in table from MySql database, but I dont know how it do this.
I tried found something example or example application with source code, but I nothing found.
Maybe someone help me with this?
I tried with node.js express:
var mysql = require('mysql');
var https = require('https');
var con = mysql.createConnection({
host: "https://adress to database",
user: "user",
password: "password",
database: "db"
});
con.connect(function(err) {
if (err) throw err;
console.log("Connected!");
});
But i get error:
Error: getaddrinfo ENOTFOUND
here is a simple way to get data from mySQL and export it as json:
var http = require('http');
var mysql = require('mysql');
var bodyParser = require("body-parser");
var express = require('express');
var app = express();
var pool = mysql.createPool({
host: 'db location',
user: 'username od db',
password: 'something',
database: 'yourdatabase',
port:3306
});
// define rute
var apiRoutes = express.Router();
var port = 9000;
apiRoutes.get('/', function (req, res) {
res.json({ message: 'API works' });
});
apiRoutes.get('/data', function (req, res, next) {
pool.getConnection(function (err, connection) {
if (err) {
console.error("error hapened: " + err);
}
var query = "SELECT * FROM imena ORDER BY id ASC";
var table = ["imena"];
query = mysql.format(query, table);
connection.query(query, function (err, rows) {
connection.release();
if (err) {
return next(err);
} else {
res.json({
success: true,
list_users: rows
});
}
});
});
});
app.use('/api', apiRoutes);
// starting
app.listen(port);
console.log('API radi # port:' + ' ' + port);
But i still suggest that you start using noSQL databases like firebase because of they are simple and faster.
In order to show data from MySQL Database, you need to provide application interface(s) to Angular environment and only then Angular can use the data. There are few techniques in which you can design interfaces, REST is the most popular though.
First you need to understand that Angular is Front-End framework and it can only send requests to backend such as Node js, PHP etc.Thus, first you need to chose your backend. Node is popular with express js module, but if you still don't have mySQL set, go for firebase real time database. If you decide node js => express => mySQL check tutorial online.
I'm currently testing my node app using ApacheBench. I run into an issue with my database which is ER_CON_COUNT_ERROR: Too many connections.
I'm using a short library on the top of MySQL node module that you can see just below
var mysql = require('mysql');
var config = require('path/to/config');
var message = require('./myMessageLib.js');
var pool = mysql.createPool({
connectionLimit : 100,
host: config.db.mysql.host,
user: config.db.mysql.user,
password: config.db.mysql.password,
database: config.db.mysql.database
});
var query = function(query_str, values, next) {
pool.getConnection((err, connection) => {
if (err) {
console.error("MySQL Fail to get a connection in pool : " + err);
if (typeof connection !== "undefined")
connection.release();
next(error, null);
return ;
}
connection.query(query_str, values, function(error, data, fields) {
connection.release();
if (error)
if (config.app.env.dev)
throw (error);
else {
next(error, null);
return (message.error("MySQL query failed : " + query_str + " / err : " + error));
}
if (data.length == 0)
next(null);
else
next(data);
})
})
}
exports.query = query;
I use this library in my model by doing something like this
var mysql = require('path/to/mysqllib');
/**
* Class PlayerModel
*/
function PlayerModel() { };
PlayerModel.prototype.get = function(id, next) {
mysql.query("SELECT ....", [id], function(player) {
// stuff
})
}
module.exports = PlayerModel;
The things is on my homepage I use different models like the one presented above and each one launch a query to get some database information. When I launch an ApacheBench with only 50 concurrency levels I got the ER_CON_COUNT_ERROR: Too many connections. So I've got the feeling that the pool isn't well made because it seems that it didn't respect the connections limit of 100 written in the short MySQL lib.
I was thinking about creating and storing the pool in the global nodejs variable to be able to share it correctly accros my modules but I'm not sure it's a good way and maybe also I'm doing something wrong on my pool implentation.
Do you have any idea or improvements to suggest ?
Thanks mates!
I figured out the issue.
My app was deploying in cluster mode. Two process were running at the same time. Because of that, two pools of 100 connections could have been created which is resulting on a total of 200 connections which is higher than the MySQL default connection limit.
Great that found a solution and here's another one with less code.
create a js file, dbconnection.js for example
var mysql = require("mysql");
var pool = mysql.createPool({
connectionLimit: 10,
host: '...',
user: '...',
password: '...',
database: '...',
dateStrings: true
});
exports.connection = {
query: function () {
var queryArgs = Array.prototype.slice.call(arguments),
events = [],
eventNameIndex = {};
pool.getConnection(function (err, conn) {
if (err) {
if (eventNameIndex.error) {
eventNameIndex.error();
}
}
if (conn) {
var q = conn.query.apply(conn, queryArgs);
q.on('end', function () {
conn.release();
});
events.forEach(function (args) {
q.on.apply(q, args);
});
}
});
return {
on: function (eventName, callback) {
events.push(Array.prototype.slice.call(arguments));
eventNameIndex[eventName] = callback;
return this;
}
};
}
};
In the other file where you want to use the connection
var db = require('./dbconnection.js');
And instead of
connection.query
Use
db.connection.query
I am using node-mysql for the first time, and I have a program with no errors, no warnings, but is not working properly... Here is the code for the program, very simple:
var mysql = require('mysql');
var connection = mysql.createConnection({
host : 'localhost',
user : 'root',
password : '',
database: 'nodetest',
port: 8080
});
connection.connect();
var usr = "BLASHDASD"
var userId = usr;
var sql = 'UPDATE userlist SET user1= ' + connection.escape(userId) + ' WHERE id=1 ';
console.log(sql);
connection.query('sql', function(err, rows, fields) {
console.log(err);
console.log("BLAHSDBKASD");
});
connection.end();
And here is the console output:
C:\wamp\www\nodePHP-master\js>node nodeTest.js
UPDATE userlist SET user1= 'BLASHDASD' WHERE id=1
But nothing is happening in my MySQL table... I even copied and pasted the UPDATE line above and just ran it as SQL code and it worked great... Need some ideas of what is going on. Thanks a bunch
EDIT:
Answered my own question... was listening on wrong port, so connection was failing. Here is updated code for those interested/search in the future:
//TEST
var mysql = require('mysql');
var connection = mysql.createConnection({
host : 'localhost',
user : 'root',
password : '',
database: 'nodetest',
port: 3306,
});
connection.connect(function(err){
if(err) {
console.log(err)
} else {
console.log("connected");
}
});
var usr = "BLASHDASD"
var userId = usr;
var sql = 'UPDATE userlist SET user1= ' + connection.escape(userId) + ' WHERE id=1 ';
console.log(sql);
connection.query(sql, function(err, rows, fields) {
console.log(err);
});
connection.end();
You are having problems with node's asynchronous nature, a very common issue when coming to Node. You also had a small but significant error in your code (you have 'sql' as a quoted string), but here is something structurally similar that should point you in the right direction.
var mysql = require('mysql');
var connection = mysql.createConnection({
host : 'locahost',
user : 'foo',
password : 'bar',
database : 'test'
});
// the callback inside connect is called when the connection is good
connection.connect(function(err){
var sql = "select 'Joe' as name from dual";
connection.query(sql, function(err, rows, fields) {
if (err) return console.log(err);
// you need to end your connection inside here.
connection.end();
console.log(rows[0].name);
});
});
You will likely start wondering about ways to avoid all these callbacks. You may wish to look at my answer to this question for a more extended mysql example as well as an alternative implementation which offers an alternative to callback-mania.
I am trying to connect to a db on my hosting and write out the result, I am not getting any error, just blank space. line like console.log('test'); put at any place always work but I am not getting any query results, what am I doing wrong?
var mysql = require('mysql');
var connection = mysql.createConnection({
host : 'wm51.wedos.net',
user : 'xxxxxx',
password : 'xxxxxx',
database: 'd57283_vs'
});
connection.connect();
var queryString = 'SELECT * FROM versus LIMIT 5';
connection.query(queryString, function(err, rows, fields) {
if (err) throw err;
for (var i in rows) {
console.log(rows[i].title);
}
});
connection.end();
(The table is called versus, has columns title, url...in adminer it's all accessible and the query works...)
Be careful with that connection.end(); call at the bottom. NodeJS is asynchronous, remember?
Try putting that at the end of the inner function after the for-loop, otherwise it will get called as soon as the query is called, possibly killing the connection you're trying to use!
perhaps mysql-server is not to be connected, when you query,or mysql-server is to be closed when you query.
var mysql = require('mysql');
var connection = mysql.createConnection({
host : 'wm51.wedos.net',
user : 'xxxxxx',
password : 'xxxxxx',
database: 'd57283_vs'
});
connection.connect();
process.nextTick(function() {
var queryString = 'SELECT * FROM versus LIMIT 5';
connection.query(queryString, function(err, rows, fields) {
connection.end();
if (err) throw err;
for (var i in rows) {
console.log(rows[i].title);
}
});
});
I believe the connection.end() statement still needs to be after the for loop. Or else your ending the connection before the loop even starts.