I'm trying to receive same version data from my MySQL (MariaDB) Server.
For better maintenance i created one connection Object to handle all database queries.
However when I query some data, it seems like it isn't executed in time, but later when the first await command appears.
dbControl.js :
var mysql = require('mysql');
function getConnection(){
let dbConnection = mysql.createConnection({
host: "localhost",
user: "root",
password: ""
});
dbConnection.connect(function (err) {
if (err) throw err;
});
this.get_version = function() {
let sql = 'SELECT * FROM versionControl ORDER BY id DESC LIMIT 1;'
dbConnection.query(sql, function (err, result) {
if (err) throw err;
console.log("vData:", result);
return result;
});
}
}
module.exports.getConnection = getConnection;
dataHandler.js:
const browserControl = require('./browserControl');
const dbControl = require('../db/dbControl');
const dbConnection = new dbControl.getConnection();
let versionData;
// Here it should be executed -->
versionData = dbConnection.get_version();
console.log(versionData);
async function get_something(){
// Here it is executed -->
const browser = await browserControl.startBrowser();
//......
}
There is a 3th file which simply controls the program. At the moment it just executes the function get_something() like:
const originData = require('./dataHandler.js');
let data = originData.get_something();
console.log(data);
P.s.: its all running with node, thanks in advance ;_)
Your get_something() is marked as async.
Call it with await get_something() or get_something().then(console.log).
Ok, I got a solution. The SQL query function returns a promise now and I created an extra "getVersion"-async-function which is waiting for the resolve of the promise. Thus the promise waits for the db answer and the rest waits until the promise is resolved.
the dataHandler.js now looks like this:
const browserControl = require('./browserControl');
const dbControl = require('../db/dbControl');
const dbConnection = new dbControl.getConnection();
async function getVersion() {
let versionData;
versionData = await dbConnection.get_version();
console.log(versionData);
}
getVersion();
async function get_something(){
const browser = await browserControl.startBrowser();
}
and the query-function now looks like this:
this.get_version = function() {
let sql = 'SELECT * FROM versionControl.lol_scraper ORDER BY id DESC LIMIT 1;'
return new Promise(resolve => {
dbConnection.query(sql, function (err, result) {
if (err) throw err;
console.log("vData:", result);
resolve(result);
})
});
P.s.: still open for smarter or more modern solutions ;_)
Related
I'm trying to update the document but the error says the query has already been executed.
MongooseError: Query was already executed: footballs.updateOne({ date: 'January 4' }, {})
app.post('/api/bookslot', async (req, res) => {
console.log(req.body);
try {
const token = req.headers['x-access-token'];
const decoded = jwt.verify(token, 'secret123');
const email = decoded.email;
const user = await UserModel.findOne({ email: email });
let sportname = req.body.selectedSport.toLowerCase();
const time = req.body.slotTime;
const seats = req.body.availableSeats - 1;
if (!sportname.endsWith('s')) {
sportname = sportname.concat('s');
}
const NewSlotModel = mongoose.model(sportname, slotSchema);
var update = {};
update[time] = seats - 1;
console.log(update);
const a = await NewSlotModel.updateOne(
{ date: req.body.slotDate },
{ $set: update },
function (err, success) {
if (err) return handleError(err);
}
);
return res.json({ status: 'ok' });
} catch (e) {
console.log(e);
res.json({ status: 'error' });
}
});
where am I going wrong?
You are using both async/await and callbacks in your code, causing mongoose to throw an error.
The actual effect of using them both is exactly the error type that you are receiving:
Query was already executed
Mongoose v6 does not allow duplicate queries.
Mongoose no longer allows executing the same query object twice. If
you do, you'll get a Query was already executed error. Executing the
same query instance twice is typically indicative of mixing callbacks
and promises, but if you need to execute the same query twice, you can
call Query#clone() to clone the query and re-execute it. See gh-7398
Duplicate Query Execution
To fix the issue, just remove the third argument from the await
NewSlotModel.updateOne
Making it:
const a = await NewSlotModel.updateOne(
{ date: req.body.slotDate },
{ $set: update }
);
Mongoose v6. Don't support callbacks any longer.. check the image.
const productCount = await Product.countDocuments((count) => count) BAD
const productCount = await Product.countDocuments(); GOOD
I am stuck at my problem because I am really new to oracle-db for node-js and JavaScript in general.
I wrote API-endpoints with JavaScript and each endpoint does an oracledb “select query”. However, my colleagues need only one endpoint which gives all results of all oracle select-queries as one JSON object. All queries are dependent on the first query, i.e. the result of the first query has to be used as a bind-parameter for the second query and so forth.
In this js-file I tried to execute two oracle-sql queries (one after the other) and use one value of the result-JSON-object of the first query as a parameter for the second query and give all results as response for the API client. But that does not work. What am I doing wrong here? With only one sql and therefore only one result it works. Thanks in advance!
Here is my code I wrote:
const oracledb = require('oracledb');
const config = require('../config/config')
oracledb.autoCommit = true
oracledb.fetchAsString = [ oracledb.DATE, oracledb.NUMBER ]
module.exports= async (req, res) => {
let connection;
try {
var sql, binds, options, result, result2, time
connection = await oracledb.getConnection(config.oracledbconnection)
// Query the data
sql = `SELECT FIRSTNr, SECONDNR,STARTTIME,MACHINE FROM MACHINELOGS WHERE Machine=:Machine AND ENDTIME > CURRENT_DATE -1 ORDER BY RUNNO ASC`;
binds = {Machine:req.params.machine}
options = {
outFormat: oracledb.OUT_FORMAT_OBJECT // query result format
//outFormat: oracledb.OBJECT // is the same as above // extendedMetaData: true, // get extra metadata
// prefetchRows: 100, // internal buffer allocation size for tuning
// fetchArraySize: 100 //internal buffer allocation size for tuning
};
result = await connection.execute(sql, binds, options);
// console.log("Metadata: ");
// console.dir(result.metaData, { depth: null });
// console.log("Query results: ");
// console.dir(result.rows, { depth: null });
//
// Show the date. The value of ORA_SDZT affects the output
sql = `SELECT TO_CHAR(CURRENT_DATE, 'DD-Mon-YYYY HH24:MI') AS CD FROM DUAL`;
time = await connection.execute(sql, binds, options);
// console.log("Current date query results: ");
// console.log(result2.rows[0]['CD']);
sql = `SELECT GRADE FROM NOTES WHERE SECONDNR=:Secondnr`
binds = {Secondnr:result.rows[0]['SECONDNR']}
result2 = await connection.execute(sql,binds,options);
options = {
outFormat: oracledb.OUT_FORMAT_OBJECT //
};
}
catch (err)
{
console.error(err);
}
finally
{
if (connection)
{
try {
await connection.close();
}
catch (err) {
console.error(err);
}
}
}
res.send(result,result2)
}
Take it back to basics. This works:
'use strict';
process.env.ORA_SDTZ = 'UTC';
const oracledb = require('oracledb');
const dbConfig = require('./dbconfig.js');
if (process.platform === 'darwin') {
oracledb.initOracleClient({libDir: process.env.HOME + '/Downloads/instantclient_19_8'});
}
let sql, options, result1, result2;
options = { outFormat: oracledb.OUT_FORMAT_OBJECT };
async function run() {
let connection;
try {
connection = await oracledb.getConnection(dbConfig);
result1 = await connection.execute(
`select 1 as myval from dual`,
[], options);
console.dir(result1.rows, { depth: null });
result2 = await connection.execute(
`select sysdate from dual where 1 = :bv`,
{bv: result1.rows[0].MYVAL},
options);
console.dir(result2, { depth: null });
} catch (err) {
console.error(err);
} finally {
if (connection) {
try {
await connection.close();
} catch (err) {
console.error(err);
}
}
}
}
run();
Then try with your datatypes.
I'm not sure what you want to do with returning 'all results'. You can build up any JS object and convert to and from JSON easily with JSON.stringify and JSON.parse.
For efficiency, you could review whether you can do all your 'queries' in a single SQL statement.
I'm quite new in Node JS and I'm trying use a mysql DB.
I have try different thing like using promise to get the result of my query but the await is skip and the promise is pending.
I'm kinda lost if someone can explain me how it works.
import * as CMD from "../command/importCommand.js";
export class Message {
constructor(bot, database) {
this.bot = bot;
this.db = database;
}
eventHandler(msg) {
const guild = msg.guild;
const prefix = this.db.getPrefixFromGuild(guild);
console.log(prefix);
//
//
}
}
import * as mysql from "mysql";
export class Database {
constructor() {
this.db = new mysql.createConnection({
host: process.env.DB_HOST,
user: process.env.DB_USER,
password: process.env.DB_PASSWORD,
database: process.env.DB_NAME
});
this.db.connect(err => {
if (err) throw err;
console.log('DB connected');
});
}
async getPrefixFromGuild(guild) {
let prefix = await this.getPrefixFromGuildId(guild.id);
return prefix;
}
async getPrefixFromGuildId(guildId) {
let prefix = await this.query("select prefix from serveur where id_serveur=" + guildId + ";");
return prefix;
}
query(sql) {
return this.db.query(sql, (err, rows) => {
if (err)
throw err;
console.log(rows);
return rows;
});
}
}
Your eventHandler is not an async function and does not await the promise returned from getPrefixFromGuild(). The console.log() statement just logs the promise, not its result. Try this:
async eventHandler(msg) {
const guild = msg.guild;
const prefix = await this.db.getPrefixFromGuild(guild);
console.log(prefix);
}
Please also note that if you access an instance of your Database class right after creation, it might not be initialized since the constructor ist not waiting for the conntect() to complet (it shouldn't but you should find another way to prevent access to an uninitialized Database object).
I am trying to retrieve all the documents from a MongoDB cluster. I have followed code I've seen online, however I am facing a small problem.
const MongoClient = require('mongodb');
const uri = "mongodb+srv://<user>:<password>#cluster0-10soy.mongodb.net/test?retryWrites=true&w=majority";
var questionsArray = [];
MongoClient.connect(uri, function (err, client) {
const database = client.db("WhatSportWereYouMadeFor");
database.collection("Questions").find({}, (error, cursor) =>{
cursor.each(function(error, item){
if (item == null){
console.log(error);
}
questionsArray.push(item);
});
})
});
module.exports = { questionsArray };
I connect fine to the database, however I've set a breakpoint at the stop variable and that gets hit before any of the documents retrieved from the database get pushed to the questions array.
I've also tried wrapping the code inside an async function and then awaiting it before the stop variable, but still that breakpoint gets hit first and only after the documents get pushed to the array.
What I would do, this wrap the whole thing into a promise, and the export that.
const MyExport = () => {
return new Promise((resolve, reject) => {
var questionsArray = [];
MongoClient.connect(uri, function (err, client) {
const database = client.db("WhatSportWereYouMadeFor");
database.collection("Questions").find({}, (error, cursor) =>{
cursor.each(function(error, item){
if (item == null){
console.log(error);
}
questionsArray.push(item);
});
resolve(questionsArray)
})
});
})
}
module.exports.questionsArray = MyExport
But then when you import it, you need to run and await it
cosnt questionsArrayFunc = require("path/to/this/file").questionsArray
const questionsArray = await questionsArrayFunc()
I hope this is what you looking for. There might be some other way, but I think this works.
I have another app which uses express and routes but this new app i was slimming it down. I know the connection string stuff is correct
script.getQuestions(connection);
script.getQuestions = function(connection,req, res){
console.log(connection);
}
I have read that some people said online to change to use a promise for async fixes this... problem is that with my function having req and res i don't know how to pass those in when i even try to refactor with a promise
"ConnectionError: Connection is closed"
"(module.js:487:32) code: 'ECONNCLOSED', name: 'ConnectionError' }"
What I call up (script) is
var sql = require('mssql');
exports.getQuestions = function(connection, req,res){
console.log(connection);
var request = new sql.Request(connection);
var query = 'select * from Question'
request.query(query).then(function(resultset){
res.json(resultset.recordset);
}).catch(function(err){
console.log(err);
//res.json(err)
})
}
it's a bit hard to understand what you're doing there. But here is an promise example to use mssql
const sql = require('mssql')
sql.connect(config).then(pool => {
// Query
return pool.request()
.input('input_parameter', sql.Int, value)
.query('select * from mytable where id = #input_parameter')
}).then(result => {
console.dir(result)
// Stored procedure
return pool.request()
.input('input_parameter', sql.Int, value)
.output('output_parameter', sql.VarChar(50))
.execute('procedure_name')
}).then(result => {
console.dir(result)
}).catch(err => {
// ... error checks
})
sql.on('error', err => {
// ... error handler
})
source: https://www.npmjs.com/package/mssql#promises