Passing multiple query objects with res.render

Question

I want to pass multiple query objects with res.render() inside my route.js. I have a select.js which contains the SQL statements and delivers the objects to my route.js. This works fine until I want to pass multiple query objects with res.render(). Any ideas on how I can pass multiple objects at once?

snippet route.js (I need to pass get_PriceData here as well)

I already query get_KategorieData but I have no clue how to handle multiple queries in one route.

router.get('/edit', (req, res, next) => {
  var speisenEintragenData = {};
  db.get_KategorieData()
    .then(({ data: kategorie_data }) => {
      res.render('speiseEintragen', { kategorie_data }); //maybe putting res.render() after the db.get?
    })
    .catch((error) => {
      console.log(error);
    });
});

select.js


const db = require('./config');

//KATEGORIEN LADEN
const get_KategorieData=()=>{
  var sql = 'SELECT * FROM Kategorie';
  return new Promise((resolve,reject) => {
    db.query(sql, function (err, data, fields) {
      if (err) reject(err);
      resolve({data});
    });
  })
}

//PREISE LADEN

const get_PriceData=()=>{
  var sql = 'SELECT * FROM preise';
  return new Promise((resolve,reject) => {
    db.query(sql, function (err, data, fields) {
      if (err) reject(err);
      resolve({data});
    });
  })
}

module.exports={
  get_KategorieData,
  get_PriceData
}

Yeah I found this post as well but I use this querys in different routes individualy. If there is no possible solution inside my route.js I can try implementing a new own combined query for this particular site — Rendolph
– Rendolph, Commented Mar 2, 2021 at 9:19
hmm yeah if I was you maybe I would be looking at SQL joins, see if i can write an SQL query which joins both Kategorie and Preise. Although I don't know your DB schema so not sure if thats possible for you — SpaceCowboy
– SpaceCowboy, Commented Mar 2, 2021 at 9:22

Abdul Haseeb · Accepted Answer · 2021-03-02 11:08:13Z

3

There are two ways to go about this. One is to stick with promises and other is to use async/await. Using promise Create a new function to query database. This is if the module you are using does not support async/await and requires a callback.

const query = ( sql ) => {
  return new Promise(( resolve, reject) => {
    db.query(sql, function (err, data, fields) {
      if (err) reject(err);
      resolve(data);
    });
  })
}
// and then you can write an async/await function to call n queries like
const get_data = async () => {
  const sql1 = '...';
  const a = await query( sql1 );
  const sql2 = '...';
  const b = await query( sql2 );
  ....
  ....
  ....
  const sqln = '...';
  const n = await query( sqln );
  return { a ,b,... ,n};
}

Or with async/await you can directly call db.query and use the response

 const get_data = async () => {
    const sql1 = '...';
    const res_1 = await db.query(sql1);
    const sql2 = '...';
    const res_2 = await db.query(sql2);
    return { a: res_1 ,b: res_2 };
  }

router.js can rewritten as

router.get('/edit', async (req, res, next) => {
  const {a:rename_a,b:rename_b and so on}=await db.get_data();
  res.render('view', { rename_a,rename_b and so on })
});

edited Mar 2, 2021 at 11:08

answered Mar 2, 2021 at 9:31

Abdul Haseeb

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6 Comments

Rendolph Over a year ago

Thanks for your solution! But now I struggle with my route.js, the object is undefinied. Do you know how to implement it inside my route.js?

Abdul Haseeb Over a year ago

Are you getting the results from the individual queries?

Rendolph Over a year ago

Now I get two Objects "[object Object] [object Object]". How can I access the values inside? I tried rename_a[0] but this doesn't work

Abdul Haseeb Over a year ago

umm... do it like this... in router.js Add const util=require('util'); on the first line. and rewrite function call to like this const res = await db.get_data(); and then console.log(util.inspect(res,false,null,true)) This will let you know what's inside the response.

Rendolph Over a year ago

I found values but unfortunately they are undefined.

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