Connect NodeJs to Oracle DB

Question

Hello I am a beginner in nodejs and I would like to connect to a remote oracle db.

Here is the code:

   const express = require('express')

const oracledb = require('oracledb')
const app = express()
const port = 3000

oracledb.getConnection(
  {
    user          : "xxx",
    password      : "xxx",
    connectString : "(tns names connection string)))"
  },
  oracledb.connExecute
)
  



app.get('/', (req, res) => {
    if(connExecute == true) {
      console.log("Conexiune reusita");
      
    } else {
      console.log("Conexiune esuata");
    }
})

app.listen(port, () => {
  console.log(`Example app listening on port ${port}`)
})

When I enter the command node index.js in the cmd I get this error:

 Example app listening on port 3000
node:internal/process/task_queues:96
    runMicrotasks();
    ^

Error: NJS-009: invalid number of parameters
    at processTicksAndRejections (node:internal/process/task_queues:96:5)

I have installed oracledb with npm. Can you please tell me what I am doing wrong or give me and working example. Thanks

You have a race condition as javascript is asynchronous. If you fail to await a promise...like you have in your code above...then the connection request is made and the code continues to execute the rest of the program before the connection has been made. This is causing the server to start before the connection is complete. See @subodhkalika 's answer below. You could also use .then(() => {}).catch(() => {}) as an alternative to async/await. Here are the official Getting Stared docs for reference: oracle.github.io/node-oracledb/doc/api.html#getstarted — Matt
– Matt, Commented Jun 20, 2022 at 6:58

subodhkalika · Accepted Answer · 2022-06-20 07:11:12Z

You missed to await your synchronous call when calling the getConnection function. As it takes some time to connect to database, the code below this line executes without waiting for connection to establish.

Also, you can simply pass a single parameter for connection using the configs to getConnection() function.

Simply remove the second parameter of getConnection.

const connection = await oracledb.getConnection(
  {
      user          : "xxx",
      password      : "xxx",
      connectString : "(tns names connection string)))"
   }
 );
 if (connection) {
    console.log("Successfully connected to DB!");
 }


 app.get('/', (req, res) => {
     if(connection) {
       console.log("Conexiune reusita");
  
     } else {
       console.log("Conexiune esuata");
     }
 })

 app.listen(port, () => {
     console.log(`Example app listening on port ${port}`)
 })

Alternatively,

As suggested by Matt in the comments, you can also use

oracledb.getConnection(
  {
      user          : "xxx",
      password      : "xxx",
      connectString : "(tns names connection string)))"
   }
 ).then((connection) => {
    if (connection) {
    console.log("Successfully connected to DB!");
    }
 }).catch((err) => {console.log(`Conexiune esuata! ${err}`);})

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