Node.js (Oracle DB) Result not printing-CodePudding

I am new to node.js. I have created the below query and although it is not returning any errors I am not seeing the result (i.e data) of the SQL.

var oracledb = require('oracledb');

oracledb.getConnection(
    {
        user: "my_user",
        password: "my_pwd",
        connectString: "database_1"
    },
    function(err, connection){
        if (err) {
            console.error(err.message);
            return;
        }
        connection.execute(
            'select * from merchant_accounts'
        ),
            {
                maxRows: 3
            },
            function(err,result)
            {
                if (err) {
                    console.error(err.message);
                    //doRelease(connection);
                    return;
                }
                console.log(result);
                //doRelease(connection);
            }
    })

CodePudding user response：

There is an extra close parenthesis ) after the string 'select * from merchant_accounts'.

        connection.execute(
            'select * from merchant_accounts'
        ),
//      ^------- oopsie-daisy!

By strange chance, what remains happens to be valid JavaScript syntax. The { } of your object literal becomes a code block. The maxRows: becomes a label. and the 3 becomes an expression. It's valid to separate expressions with commas, and the function that follows is legally defined but discarded as part of the comma-separated expression.

Unfortunate happenstance, I suppose, for the reason that normally you'd get a syntax error by adding an extra parenthesis like that -- but in this case, by fluke, the syntax is valid so you didn't get a syntax error.

You are, of course, missing a close parenthesis too. The close parenthesis actually belongs here:

        console.log(result);
        //doRelease(connection);
      })
//     ^------ ah!  much better

CodePudding user response：

Save yourself some headaches and follow all the current node-oracledb examples and use the async/await style instead of the older callback style you show.

Start with examples.js. Something like:

'use strict';

process.env.ORA_SDTZ = 'UTC';

const oracledb = require('oracledb');

const dbConfig = { user: 'cj', password: process.env.NODE_ORACLEDB_PASSWORD, connectString: 'localhost/orclpdb1' };

let libPath;
if (process.platform === 'win32') {           // Windows
  libPath = 'C:\\oracle\\instantclient_19_14';
} else if (process.platform === 'darwin') {   // macOS
  libPath = process.env.HOME   '/Downloads/instantclient_19_8';
}
if (libPath && fs.existsSync(libPath)) {
  oracledb.initOracleClient({ libDir: libPath });
}

let sql, binds, options, result;
sql = `select * from merchant_accounts`;
binds = [];
options = { outFormat: oracledb.OUT_FORMAT_OBJECT };

async function run() {
  let connection;

  try {
    connection = await oracledb.getConnection(dbConfig);

    result = await connection.execute(sql, binds, options);
    console.dir(result, { depth: null });

  } catch (err) {
    console.error(err);
  } finally {
    if (connection) {
      try {
        await connection.close();
      } catch (err) {
        console.error(err);
      }
    }
  }
}

run();

Also don't use maxRows to limit the number of records shown, read the doc Limiting Rows and Creating Paged Datasets.