Example of querying using Promises

var
   fb = require("node-firebird"),  // firebird lib
   q = require('q'),               // promises lib
   db,                             // this will store the global db object 
   cfg;                            // cfg object  

cfg =
{
   host: '127.0.0.1',
   port: 3050,
   database: 'C:\\A.FDB',
   user: 'SYSDBA',
   password: 'masterkey'
};


/*------------------------------ UTILITY -------------------------------*/
function ab2str(buf) {
   return String.fromCharCode.apply(null, new Uint16Array(buf));
}

function str2ab(str) {
   var buf = new ArrayBuffer(str.length*2); // 2 bytes for each char
   var bufView = new Uint16Array(buf);
   for (var i=0, strLen=str.length; i<strLen; i++) {
      bufView[i] = str.charCodeAt(i);
   }
   return buf;
}

/*------------------------------ CONNECT/DISCONNECT -------------------------------*/
connectToDB = function (acfg){
   var def = q.defer();

   fb.attach( acfg,
      function(err, db){
         err ? def.reject(err) : def.resolve(db);
      }
   );
   return def.promise;
};

disconnectFromDB = function() {
   db.detach(
      function(){
         console.log('database detached');
      }
   );
};

/*------------------------------ QUERY -------------------------------*/
queryDB = function(sql){
   var def = q.defer();

   connectToDB(cfg).then(
      // success
      function(dbconn){
         db = dbconn;
         db.query(sql,
         function(err, rs){
            err ? def.reject(err) : def.resolve(rs);
         });
      },
      // fail
      function(err)  {
         console.log(err);
      }
   );
   return def.promise;
};


/*------------------------------------------------
example of querying using promises
------------------------------------------------*/
queryDB( "select id, name from users order by id").then(
      // success
      function(rs) {
         rs.forEach( function(row){
            console.log( row.id, ab2str(row.name));
         });
         disconnectFromDB();
      },
      // fail
      function(err)  {
         console.log(err);
         disconnectFromDB();
      }
   );