I'm trying to call a saved stored procedure from SQL in my node app. my server is connected and I am able to execute my selectRandom5 saved proc with no problems.
the issue I am having is when I try to do a getById where I need to declare the #Id input. I've tried a couple of variations of the function with no luck, here are two I've tried.
the error message I get with this is UnhandledPromiseRejectionWarning: RequestError: Incorrect syntax near '?'.
selectById(req, res) {
var theId = req.params.id;
// connect to your database
sql.connect(config, function (err) {
if (err) console.log(err);
// create Request object
var request = new sql.Request();
// query to the database and get the records
request.query("CALL Addresses_SelectById(?)", [theId], function (err, recordset) {
if (err) console.log("connect", err);
// send records as a response
res.send(recordset);
console.log(recordset);
});
});
}
and then there's this other function I've tried, and the error message I get from this is 'Must declare the scalar variable "#Id".'
selectById(req, res) {
var theId = req.params.id;
// connect to your database
sql.connect(config, function (err) {
if (err) console.log(err);
// create Request object
var request = new sql.Request();
// query to the database and get the records
request.query(`SET #Id = ${theId}CALL Addresses_SelectById(#Id)`, function (err, recordset) {
if (err) console.log("connect", err);
// send records as a response
res.send(recordset);
console.log(recordset);
});
});
}
I just want to be able to pass parameters to SQL to be able to create update or get by but so far I haven't been able to figure out the proper way to pass the parameters.
any help would be appreciated! thanks guys
I FOUND IT GUYS!
selectById(req, res) {
var theId = req.params.id;
// connect to your database
sql.connect(config, function (err) {
if (err) console.log(err);
// create Request object
var request = new sql.Request();
// query to the database and get the records
request.input("Id", sql.Int, theId);
request.execute("Addresses_SelectById", function (err, recordset) {
if (err) console.log("connect", err);
// send records as a response
res.send(recordset);
console.log(recordset);
});
});
I changed it to this and it works
Problem 1:
Suggested alternate syntax:
selectById(req, res) {
var theId = req.params.id;
let sql = `CALL Addresses_SelectById(?)`;
connection.query(sql, theId, (error, results, fields) => {
if (error) {
return console.error(error.message);
}
console.log(results[0]);
// Possibly stringify "results" to JSON before sending...
res.send(results);
});
}
Related
I am new at Node.js and I want to find something from database by using select query.
Here is my code.
var address = socket.request.client._peername.address;
var ip_addrss = address.split("::ffff:");
let mine = ip_addrss[1];
var location = iplocation_find(mine);
connection.connect( function () {
// insert user data with IP, location --- has got a status.
let stranger = "";
var values = [];
if (mine == null){
mine = "local server";
}
values.push(mine);
values.push('location');
var sql = "INSERT INTO user_list (IP_address, location) VALUES (?)";
connection.query(sql, [values], function (err, res){
if (err) throw err;
});
// control chatting connection between users
connection.query("SELECT IP_address FROM user_list WHERE status = ? AND location = ?", [0, "location"], function (err, res){
if (err) throw err;
stranger = res[0].IP_address;
console.log(stranger);
});
var room_users = [];
room_users.push(mine);
room_users.push(stranger);
console.log(room_users);
connection.query("INSERT INTO chatting_status (IP_client_1, IP_client_2) VALUES (?)", [room_users], function (err, res){
if (err) throw err;
console.log('inserted');
});
});
Now the problem is "stranger". It is not working anymore. Just always null.
Please tell me how I can return value in mysql query statement.
on my console, shows this.
[ 'local server', '' ]
127.0.0.1
inserted
[ '192.168.1.100', '' ]
127.0.0.1
inserted
Above, 'local server' and '192.168.1.100' are values of mine. And also '127.0.0.1' is the value of stranger only in query. But out of query it is just null.
You are using asynchronous operations with your .connect() and .query() calls. To sequence code with asynchronous callbacks like this, you have to continue the flow of control inside the callback and then communicate back errors or result via a callback.
You could do that like this:
let address = socket.request.client._peername.address;
let ip_addrss = address.split("::ffff:");
let mine = ip_addrss[1];
let location = iplocation_find(mine);
function run(callback) {
connection.connect( function () {
// insert user data with IP, location --- has got a status.
let values = [];
if (mine == null){
mine = "local server";
}
values.push(mine);
values.push('location');
var sql = "INSERT INTO user_list (IP_address, location) VALUES (?)";
connection.query(sql, [values], function (err, res){
if (err) return callback(err);
// control chatting connection between users
connection.query("SELECT IP_address FROM user_list WHERE status = ? AND location = ?", [0, "location"], function (err, res){
if (err) return callback(err);
let stranger = res[0].IP_address;
console.log(stranger);
let room_users = [];
room_users.push(mine);
room_users.push(stranger);
console.log(room_users);
connection.query("INSERT INTO chatting_status (IP_client_1, IP_client_2) VALUES (?)", [room_users], function (err, res){
if (err) return callback(err);
console.log('inserted');
callback(null, {stranger: stranger, room_users: room_users});
});
});
});
});
}
run((err, result) => {
if (err) {
console.error(err);
} else {
console.log(result);
}
});
Personally, this continually nesting callback code is a drawback of writing sequenced asynchronous code with plain callbacks. I would prefer to use the promise interface to your database and write promise-based code using async/await which will allow you to write more linear looking code.
From my Model, I fetch some articles from a MySQL database for a user.
Model
var mysql = require('mysql');
var db = mysql.createPool({
host: 'localhost',
user: 'sampleUser',
password: '',
database: 'sampleDB'
});
fetchArticles: function (user, callback) {
var params = [user.userId];
var query = `SELECT * FROM articles WHERE userId = ? LOCK IN SHARE MODE`;
db.getConnection(function (err, connection) {
if (err) {
throw err;
}
connection.beginTransaction(function (err) {
if (err) {
throw err;
}
return connection.query(query, params, function (err, result) {
if (err) {
connection.rollback(function () {
throw err;
});
}
//console.log(result);
});
});
});
}
This is working and the function fetches the result needed. But it's not returning the result to the controller function (I am returning it but I'm not able to fetch it in the controller function. I guess, I did something wrong here).
When I did console.log(result) this is what I got.
[ RowDataPacket {
status: 'New',
article_code: 13362,
created_date: 2017-10-22T00:30:00.000Z,
type: 'ebook'} ]
My controller function looks like this:
var Articles = require('../models/Articles');
exports.getArticle = function (req, res) {
var articleId = req.body.articleId;
var article = {
userId: userId
};
Articles.fetchArticles(article, function (err, rows) {
if (err) {
res.json({ success: false, message: 'no data found' });
}
else {
res.json({ success: true, articles: rows });
}
});
};
Can anyone help me figure out what mistakes I made here?
I'm pretty new to nodejs. Thanks!
The simple answer is that you're not calling the callback function, anywhere.
Here's the adjusted code:
fetchArticles: function (user, callback) {
var params = [user.userId];
var query = `SELECT * FROM articles WHERE userId = ? LOCK IN SHARE MODE`;
db.getConnection(function (err, connection) {
if (err) {
// An error. Ensure `callback` gets called with the error argument.
return callback(err);
}
connection.beginTransaction(function (err) {
if (err) {
// An error. Ensure `callback` gets called with the error argument.
return callback(err);
}
return connection.query(query, params, function (err, result) {
if (err) {
// An error.
// Rollback
connection.rollback(function () {
// Once the rollback finished, ensure `callback` gets called
// with the error argument.
return callback(err);
});
} else {
// Query success. Call `callback` with results and `null` for error.
//console.log(result);
return callback(null, result);
}
});
});
});
}
There's no point in throwing errors inside the callbacks on the connection methods, since these functions are async.
Ensure you pass the error to the callback instead, and stop execution (using the return statement).
One more thing, without knowing the full requirements of this:
I'm not sure you need transactions for just fetching data from the database, without modifying it; so you can just do the query() and skip on using any beginTransaction(), rollback() and commit() calls.
exports.saveUserInterfaceConfig = function(req,res){
var body = req.body;
console.log('body:['+JSON.stringify(body)+']');
var mysql = require('mysql');
var UiConfigId = [];
var connection = getDBConnection();
if(body && connection){
connection.beginTransaction(function(err){
if (err) {
/*var errorObj = {error:{code:0, text:'backend error'}};
return res.json(200, errorObj);*/
throw err;
}
var companyId = body.companyId;
var moduleId = body.moduleId;
var submoduleId = body.submoduleId;
var formfieldsId = body.formfieldsId;
for(var index3 in formfieldsId){
var UIConfigInfo = {Company_CompanyId: companyId, Modules_ModuleId: moduleId, SubModule_SubModuleId: submoduleId, SubmoduleFieldConfig_SubmoduleFieldConfigId: formfieldsId[index3]};
var saveUIConfigQuery = 'INSERT INTO ui_config SET ?';
connection.query(saveUIConfigQuery, UIConfigInfo, function(err, result) {
if (err) {
return connection.rollback(function() {
throw err;
});
}
UiConfigId.push(result.insertId);
console.log('result:['+JSON.stringify(result)+']');
connection.commit(function(err) {
if (err) {
return connection.rollback(function() {
connection.end(function(err) {
// The connection is terminated now
});
throw err;
});
} else {
connection.end(function(err) {
// The connection is terminated now
});
}
return res.json(200,{UiConfigId: UiConfigId});
console.log('UiConfigId:['+JSON.stringify(UiConfigId)+']');
console.log('success!');
// connection.release();
});
})
}
})
}
}
I have the above in my Node API. I have to execute same query in loop more than once . but im facing an issue placing the return statement for which im getting the below error.
Error: Can't set headers after they are sent.
at ServerResponse.OutgoingMessage.setHeader (_http_outgoing.js:335:11)
How do I fix it?
you are calling res.json multiple times in a loop, that is the reason you are getting that error..
In Simple Words., This type of error will get when you pass statements or something after sending response.
for example:
res.send("something response");
console.log("jhgfjhgsdhgfsdf");
console.log("sdgsdfhdgfdhgsdf");
res.send("sopmething response");
it generates, what the error u got.!! Beccoz once the response have been sent, the following res.send Will not be executed..because, we can send response only once per a request.!!
for this you need to use the callbacks.
Good Luck
The reason you are getting that error is because you are calling res.json multiple times in a loop.
First of all, you should be using a callback mechanism to execute the query in a loop. For'ing over it can mess up by executing multiple queries before even the others are finished.
And coming to the response, it also should be done through a callback based on a condition. Condition can be to check whether you have finished all the queries successfully.
Here is a page with good info on exactly what you need:
https://mostafa-samir.github.io/async-iterative-patterns-pt1/
I have this code:
server.js:
var sql = require('./libs/mysql');
app.get('/status', function(req, res) {
res.send(sql.readName('1600'));
});
mysql.js:
exports.readName = function(name){
var connection = mysql.createConnection(option);
connection.connect();
connection.query('SELECT id FROM asterisk.users WHERE name= '+name, function (err, rows, fields) {
console.log('mysql: ' +rows[0].id);
return(rows[0].id);
});
Now, when I send GET http://mydomain.com/status I can not receive responce. But in console log I see correct answer. Where is my error?
Most disk reading/DB access in node.js is done asynchronously. This allows node.js to be as fast as it claims. You need to use callback functions to handle the result of these read operations. If you are familiar with ajax, the concept is similar.
You are returning from connection.query which runs asynchronously. This is returned nowhere. readName actually returns nothing. What you need to do is actually pass in the callback that returns the value:
app.get("/status", function (req, res) {
sql.readName("1600", function (err, rows, fields) {
/* handle err */
res.send(rows[0].id);
});
});
This callback has to be called of course:
exports.readName = function (name, cb) {
/* snip */
connection.query(query + name, cb);
});
You can't get the result because the return statement is in the function function (err, rows, fields). You can use callback like this
var sql = require('./libs/mysql');
app.get('/status', function(req, res) {
sql.readName('1600', function(result){
res.send(result);
});
});
exports.readName = function(name, callback){
var connection = mysql.createConnection(option);
connection.connect();
connection.query('SELECT id FROM asterisk.users WHERE name= '+name,
function (err, rows, fields) {
console.log('mysql: ' +rows[0].id);
callback(rows[0].id);
});
}
Thanks for helping. I find http error causes described upper. Error appear if I use callback functions like this callback(row[0].id), but if we use syntax like this callback('id: '+row[0].id) everything it's ok. So when we send res.send(response) we cant send unnamed data, need to put there some descriptions.
So, my final code look like this:
server.js
var sql = require(./mysql);
app.get('/status', function(req, res) {
sql.readName('1600', function(result){
res.send(result);
});
});
mysql.js
var mysql=require(mysql);
exports.readName = function(name, callback){
var connection = mysql.createConnection(option);
connection.connect();
connection.query('SELECT id FROM asterisk.users WHERE name= '+name,
function (err, rows, fields) {
if(err) callback(err);
else{
console.log(rows[0].id);
callback('ID: '+rows[0].id);
}
});
return true;
};
What i'am trying to achieve is to make DB query inside closure. Return data and then send stuff to user. I understand that best practice is to use database pooling. Problem is that query is not sync.
Simplified code:
server.js
var express = require('express'),
app = express(),
server = require('http').createServer(app),
mysql = require('mysql');
app.set('DB:pool', mysql.createPool(process.env.DATABASE_URL));
var myClosure = require('./closure.js')(app));
app.get('/somepage', function(req, res) {
var data = myClosure.myquery();
res.send(data);
});
app.get('/anotherpage', function(req, res) {
var data = myClosure.myquery();
res.send(data);
});
app.listen(3000);
closure.js
function myClosure(app) {
var pool = app.get('DB:pool');
return {
myquery: function(inp) {
pool.getConnection(function(err, db) {
if (err) throw err;
db.query('SELECT * FROM table', function(err, rows, fields) {
if (err) throw err;
data = rows[0]
db.release();
});
});
return data;
}
};
}
module.exports = myClosure;
In examples i found all DB related stuff were made in route callback and response was sent in query callback. But way i'm trying to do it is not working as myquery returns undefined because sql query is not done there.
So what is correct way to handle querys ?
Make your query-function handle a callback too:
// server.js
app.get('/somepage', function(req, res) {
myClosure.myquery(function(err, data) {
// TODO: handle error...
res.send(data);
});
});
// closure.js
...
myquery: function(callback) {
pool.getConnection(function(err, db) {
if (err) return callback(err);
db.query('SELECT * FROM table', function(err, rows, fields) {
// release connection before we return anything, otherwise it
// won't be put back into the pool...
db.release();
if (err) return callback(err);
callback(null, rows[0]);
});
});
}
(I left out the inp argument because that didn't seem to be used)