Not getting parameter name on querying oracle db from nodejs

Question

I am trying to query oracledb from nodejs. Below is the code that i use for querying

exports.simpleExecute = function(query,bindParams, options,callback) {
try {
pool.getConnection(function(err, connection) {
  if (err) {
    console.log(err);
  }
  connection.execute(query,bindParams, options,function(err, data) {
    console.log(data);
    if (err) {
      console.log(err);
      response.send({})
    }
    callback(null, data);
  })
})
} catch (err) {
callback(err, null);
}
}

Below is the code that is making the request:

  database.simpleExecute(query1,{},{outFormat: database.OBJECT},function(err, data1) {
  // console.log(data2);
  if (err) {
    console.log(err);
    response.send({});
  }
  var percentChange = ((data1.rows[0].COUNT - data1.rows[0].COUNT) / data2.rows[0].COUNT) * 100;
  var data = [data1.rows[0].COUNT, percentChange];
  response.send(data);
});

where query1 is : "SELECT count(distinct user_id) count_value FROM chatlog where trunc(timestamp) between to_date('2017-09-09','YYYY-MM-DD') and to_date('2017-10-08','YYYY-MM-DD')"

The problem is that the data1.rows parameter instead of coming as array of object is coming just as an array. Previously i tried some another method for connecting and querying taken from https://jsao.io/2015/03/making-a-wrapper-module-for-the-node-js-driver-for-oracle-database/ and things seems to be working well in that case.I was also getting the name of the parameter in data1.rows .The output that i am getting when i print the data1 is:

{ rows: [ [ 1 ] ],
resultSet: undefined,
outBinds: undefined,
rowsAffected: undefined,
metaData: [ { name: 'COUNT' } ] }

Answer 1

There are a couple of problems with your simpleExecute function. The first is that you're wrapping everything in a try/catch block. However, you can't catch exceptions that occur during async operations like getConnection and execute .

The next problem is that you're not releasing the connection back to the pool after your done using it.

Finally, simpleExecute has a reference to response.send({}) , which it shouldn't as the calling function is handling that.

Here's an example of how you could write this:

const oracledb = require('oracledb');
const config = require('./dbConfig.js');
let pool;

// Callback style simpleExecute
function simpleExecute(query, bindParams, options, callback) {
  pool.getConnection(function(err, conn) {
    if (err) {
      callback(err);
      return
    }

    conn.execute(query, bindParams, options, function(err, result) {
      if (err) {
        callback(err);
      } else {
        callback(null, result);
      }

      conn.close(function(err) {
        if (err) {
          console.log('error closing conn', err);
        }
      });
    });
  });
}

// Example of using simpleExecute after creating the pool
oracledb.createPool(config, function(err, p) {
  if (err) {
    throw err;
  }

  pool = p; 

  simpleExecute(
    'select count(*) cnt from dual',
    {},
    {
      outFormat: oracledb.OBJECT
    },
    function(err, result) {
      if (err) {
        console.log(err);
        return;
      }

      console.log(result.rows); // [ { CNT: 1 } ]
    }
  );
});

You might find this series on async patterns useful: https://jsao.io/2017/06/how-to-get-use-and-close-a-db-connection-using-various-async-patterns/