DBMS Assignment 12

Title: Map reduce operation with suitable example using MongoDB.
Problem Statement: Create an orders collection with fields customer id, order date, status, price and items,quantity. Execute following queries using mapreduce.
Perform map reduce operation on orders collection .Perform following  queries using map reduce.
    1. Display total price per customer.
var map=function(){emit(this.Cust_id,this.Amt);}
> var red=function(keys,values){return Array.sum(values);}
> db.orders.mapReduce(map,red,{'out':'neworders'})
{
	"result" : "neworders",
	"timeMillis" : 585,
	"counts" : {
		"input" : 6,
		"emit" : 6,
		"reduce" : 3,
		"output" : 3
	},
	"ok" : 1
}
db.neworders.find().pretty()
{ "_id" : "A1", "value" : 95000 }
{ "_id" : "B1", "value" : 52000 }
{ "_id" : "C1", "value" : 36000 }
    2. Display total price per customer having status= D
 db.orders.mapReduce(map,red,{'query':{Status:'D'},'out':'new1'})
{
	"result" : "new1",
	"timeMillis" : 358,
	"counts" : {
		"input" : 2,
		"emit" : 2,
		"reduce" : 0,
		"output" : 2
	},
	"ok" : 1
}
 db.new1.find().pretty()
{ "_id" : "A1", "value" : 90000 }
{ "_id" : "B1", "value" : 12000 }
    3. Display total price for Status =P
 db.orders.mapReduce(map,red,{'query':{Status:'P'},'out':'new2'})
{
	"result" : "new2",
	"timeMillis" : 376,
	"counts" : {
		"input" : 4,
		"emit" : 4,
		"reduce" : 1,
		"output" : 3
	},
	"ok" : 1
}
> db.new2.find().pretty()
{ "_id" : "A1", "value" : 5000 }
{ "_id" : "B1", "value" : 40000 }
{ "_id" : "C1", "value" : 36000 }
    4. Finding count of all keys in orders collection
db.orders.mapReduce(map1,red1,{'out':'new3'})
    5. {
    6. 	"result" : "new3",
    7. 	"timeMillis" : 356,
    8. 	"counts" : {
    9. 		"input" : 6,
    10. 		"emit" : 62,
    11. 		"reduce" : 11,
    12. 		"output" : 11
    13. 	},
    14. 	"ok" : 1
    15. }
    16. > db.new3.find().pretty()
    17. { "_id" : "Amt", "value" : { "CountOfKey" : 6 } }
    18. { "_id" : "Cust_id", "value" : { "CountOfKey" : 6 } }
    19. { "_id" : "Cust_name", "value" : { "CountOfKey" : 6 } }
    20. { "_id" : "DtOfOrder", "value" : { "CountOfKey" : 6 } }
    21. { "_id" : "Email_id", "value" : { "CountOfKey" : 2 } }
    22. { "_id" : "Item_name", "value" : { "CountOfKey" : 6 } }
    23. { "_id" : "Order_id", "value" : { "CountOfKey" : 6 } }
    24. { "_id" : "Phone_no", "value" : { "CountOfKey" : 6 } }
    25. { "_id" : "Qty", "value" : { "CountOfKey" : 6 } }
    26. { "_id" : "Status", "value" : { "CountOfKey" : 6 } }
    27. { "_id" : "_id", "value" : { "CountOfKey" : 6 } }