function connectToDb() {
  console.log('made a connection to database');
  return "dbConnection";
}

var connection = connectToDb();
var dbQueryWithoutClosure = function (queryParam) {
//   var connection = connectToDb();
  console.log('request without closure param: ' + queryParam + ' to db with connection: ' + connection);
}

dbQueryWithoutClosure("a");
dbQueryWithoutClosure("b");
dbQueryWithoutClosure("c");


function dbQueryFactory() {
  var conn = connectToDb();
  return function (queryParam) {
    console.log('request with closure param: ' + queryParam + ' to db with connection: ' + conn);
  };
}

var dbQueryWithClosure = dbQueryFactory();
dbQueryWithClosure("a");
dbQueryWithClosure("b");
dbQueryWithClosure("c");