Map ReReduce and join example

map_rereduce.js

map = function() {
  if (this.is_cancelled == false) {
    data = {  bookings: [ this._id ],
              booking_amount: this.booking_amount, 
              amt_received: 0,
              cancellations: 0
    }
  } else {
    data = {  bookings: [],
              booking_amount: 0,
              amt_received: 0,
              cancellations: 1
    }
  emit(this.resource_id, data);
};


reduce = function(key, values) {
  var r = { bookings: [], booking_amount: 0, amt_received: 0, cancellations: 0 }
  values.forEach(function(value) {
    r.booking_amount += value.booking_amount;
    r.amt_received += value.amt_received;
    r.cancellations += value.cancellations;

    if(value.bookings.length > 0) {
      r.bookings = r.bookings.concat(value.bookings);
    }
  });
  return r;
};

db.bookings.mapReduce(map, reduce,  
          {
            query: { resource_type: "Distributor" },
            out: 'distributorReport'
          }
);


mapStat = function() {
  emit('booking_ids', { bookings: this.value.bookings });
}

reduceStat = function(key, values) {
  r = { bookings: [] }
  values.forEach(function(value) {
    r.bookings = r.bookings.concat(value.bookings);
  });
  return r;
}

db.distributorReport.mapReduce(mapStat, reduceStat, { out: "tmpBookings" } );

mapVoucher = function() {
  emit(this.resource_id, { bookings: [], booking_amount: 0, amt_received: this.credit_amount, cancellations: 0 });
}

db.vouchers.mapReduce(mapVoucher, reduce,
          {
            query: { resource_type: "Distributor", booking_id: { $in: db.tmpBookings.findOne().value.bookings } },
            out: { reduce: 'distributorReport'}
          }
);