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[ERROR] When I Connect postgresql and query in multiple different scripts

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Asian black bear posted this in #help-forum
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Asian black bearOP
I'm tryin to make one file that connects to the database then import just the connection to the scripts I need to do anything with the database like queries.

connect.js
`use server`;
import { Client } from 'pg';
import db from 'dbDetails.js';




var client = () => {

    client = new Client(db);
   return client.connect();
}
export default client;


but whenever I try to imported I get this error 

[ Server ] Error: {imported module [project]/clientConn.js [app-rsc] (ecmascript)}.default.query is not a function


how to do it right ?
Answered by Alfonsus Ardani
try

import { Client } from 'pg';
import db from 'dbDetails.js';

var client = new Client(db);
return client.connect();

export default client;
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70 Replies

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Asian black bearOP
also please tell me if that's the right approach
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Asian black bearOP
up
up
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Alfonsus Ardani
I'm tryin to make one file that connects to the database then import just the connection to the scripts I need to do anything with the database like queries.

Can you try removing 'use server' and importing it in a server component to see if it works?
is this the right approach ?
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Alfonsus Ardani
we will see in a moment
you declared client as a function, and inside you declared client as new Client(db)
that is confusing
also try using let or const instead of var since var is pretty archaic
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@Alfonsus Ardani you declared `client` as a function, and inside you declared `client` as new Client(db)
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Asian black bearOP
`use server`;
import { Client } from 'pg';
import db from 'dbDetails.js';
var xx = () => { return Client(db).connect();}
export default xx;

same error
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Alfonsus Ardani
remove 'use server'
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Asian black bearOP
ok
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@Alfonsus Ardani remove 'use server'
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Asian black bearOP
that made no difference
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Alfonsus Ardani
something wrong with
import db from 'dbDetails.js';
then
are you using typescript?
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Asian black bearOP
not really because I used to connect on the same script using import db from 'dbDetails.js'; and it worked, I can query normally if Im connecting the client on the same script but if I'm importing it, it doesnt work.
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@Alfonsus Ardani are you using typescript?
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Asian black bearOP
yes I think i have .ts formates
im following a toturial im new to react and nextJS
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Asian black bearOP
sure
Image
im using VS 2019
im following this toturial
https://nextjs.org/learn/dashboard-app/mutating-data
they are using '@vercel/postgres'; but Im hosting pg locally
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Alfonsus Ardani
im interested to know if your project is using typescript or javascript
i dont think you can mix it up
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Alfonsus Ardani
try

import { Client } from 'pg';
import db from 'dbDetails.js';

var client = new Client(db);
return client.connect();

export default client;
Answer
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@Alfonsus Ardani try tsx import { Client } from 'pg'; import db from 'dbDetails.js'; var client = new Client(db); return client.connect(); export default client;
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Asian black bearOP
[ Server ] Error: Cannot access '{default export}' before initialization
sorry for the delay i have a 1 yearsOld child
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@Asian black bear sorry for the delay i have a 1 yearsOld child
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Alfonsus Ardani
its fine, how are they? i hope they are healthy
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@Alfonsus Ardani its fine, how are they? i hope they are healthy
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Asian black bearOP
thank u that is very sweet, yes they are 🙂
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@Alfonsus Ardani can we see `dbDetails.js` ?
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Asian black bearOP
sure its pretty basic 
const { Client } = require('pg');

const db = new Client({
    user: 'user1',
    host: 'localhost',
    database: 'nextJSdb',
    password: "123456",
    port: 5332,
});
export default db ;
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Alfonsus Ardani
is it a typescript file or a javascript file?
is your project using typescript or no typescript?
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@Alfonsus Ardani is it a typescript file or a javascript file?
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Asian black bearOP
im sorry how to know this ?
im new
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Alfonsus Ardani
check the name of the file
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Asian black bearOP
its a js file
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Alfonsus Ardani
i see
Im not sure why its wrong
do you have a github repository?
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Asian black bearOP
nope
its kinda odd, why can i just pass it
i've also noticed that db itself is Client
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Alfonsus Ardani
yeah
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Asian black bearOP
so db.connect() should be fine right ?
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Alfonsus Ardani
yeah\
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Asian black bearOP
Im so sorry for the delay again - its impossible to control a 1yearOld
-------------------
SUMMERY:
--------------------
so basically, I have 2 .ts scripts that attempts to connect to the database for two different reasons
dbDetails.js
const { Client } = require('pg');

const db = new Client({
    user: 'user1',
    host: 'localhost',
    database: 'nextJSdb',
    password: "123456",
    port: 5332,
});
export default db ;


and then the other two ts files connect to it the same way
import { Client } from 'pg';
import db from 'dbDetails';

  const client:Client = new Client(db);
  client.connect().catch(err => console.error('Failed to connect to the db [ERROR]: ', err));


this code works will when only 1 file is connected when I connect the other file I get an error 

Failed to connect to the db [ERROR]:  [AggregateError: ] { code: 'ECANCELED' }
I've also tried to make and export client as mentioned above and import it in the two ts files
import { Client } from 'pg';
import db from 'dbDetails.js';

var client = new Client(db);
return client.connect();

export default client;

but again it rose an error [ Server ] Error: Cannot access '{default export}' before initialization
I've tried many things none of them worked
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Yacare Caiman
this is how you connect to with pg import pg from "pg"; export const pool = new pg.Pool({ host: process.env.PG_HOST, user: process.env.PG_USER, password: process.env.PG_PASSWORD, port: 5432 || process.env.PG_PORT, database: process.env.PG_DATABASE, idleTimeoutMillis: 30000, ssl: { rejectUnauthorized: false } });
and futher
const client = await pool.connect();
const result = await client.query(SELECT * Users;,[]);
more specifically const query = "SELECT * FROM users WHERE id = $1 AND email = $2;"; const values = [123, "test@example.com"];
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@Alfonsus Ardani try tsx import { Client } from 'pg'; import db from 'dbDetails.js'; var client = new Client(db); return client.connect(); export default client;
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Asian black bearOP
I finally got it to work 
const client = new Client(db);
client.connect();
export default client;

I have no idea why it didnt work bk then maybe the error was caused by something else
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Yacare Caiman
Client makes new req each time when u query data base. And create lot of connections
Pool re-use the previous connections
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@Yacare Caiman Pool re-use the previous connections
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Yacare Caiman
If connections exist
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@Yacare Caiman If connections exist
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Asian black bearOP
I love this ofc!
are all connections session based?
sorry for asking too many questions, Im new to react and nextJS
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@Asian black bear I love this ofc! are all connections session based?
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Yacare Caiman
Yes, both client and Pool connections are session based!