Implement aggregation and indexing with suitable example using MongoDB.

1. Practical No:11
Problem Statement: Implement aggregation and indexing with suitable example
using MongoDB.
*Index*
> use prac11
switched to db prac11
> db.stud.insert({_id:1,rollno:28,name:"Shail",dept:10});
> db.stud.insert({_id:2,rollno:26,name:"Shivesh",dept:10});
> db.stud.find();
{ "_id" : 1, "rollno" : 28, "name" : "Shail", "dept" : 10 }
{ "_id" : 2, "rollno" : 26, "name" : "Shivesh", "dept" : 10 }
> db.stud.insert({_id:3,rollno:22,name:"Alquama",dept:11});
> db.stud.insert({_id:4,rollno:33,name:"Swapnil",dept:11});
>
> db.stud.find().pretty();
{ "_id" : 1, "rollno" : 28, "name" : "Shail", "dept" : 10 }
{ "_id" : 2, "rollno" : 26, "name" : "Shivesh", "dept" : 10 }
{ "_id" : 3, "rollno" : 22, "name" : "Alquama", "dept" : 11 }
{ "_id" : 4, "rollno" : 33, "name" : "Swapnil", "dept" : 11 }
db.stud.getIndexes();
[
{
"v" : 1,
"key" : {
"_id" : 1
},
"ns" : "prac11.stud",
"name" : "_id_"
}
]
db.stud.ensureIndex({name:1});
> db.stud.getIndexes();
[
{
"v" : 1,
"key" : {
"_id" : 1
},
"ns" : "prac11.stud",
"name" : "_id_"
},
{
"v" : 1,
"key" : {
"name" : 1
},
"ns" : "prac11.stud",
"name" : "name_1"
}
db.stud.getIndexes();
[
{
"v" : 1,
"key" : {
"_id" : 1
},
"ns" : "prac11.stud",
"name" : "_id_"
},
{

2. "v" : 1,
"key" : {
"name" : 1
},
"ns" : "prac11.stud",
"name" : "name_1"
},
{
"v" : 1,
"key" : {
"rollno" : 1
},
"unique" : true,
"ns" : "prac11.stud",
"name" : "rollno_1"
}
db.system.indexes.find();
{ "v" : 1, "key" : { "_id" : 1 }, "ns" : "prac11.stud", "name" : "_id_" }
{ "v" : 1, "key" : { "name" : 1 }, "ns" : "prac11.stud", "name" : "name_1" }
{ "v" : 1, "key" : { "rollno" : 1 }, "unique" : true, "ns" : "prac11.stud",
"name" : "rollno_1" }
{ "v" : 1, "key" : { "_id" : 1 }, "ns" : "prac11.item", "name" : "_id_" }
--------------------------------------------------------------------------------
------------------------
*Aggergation*
db.item.insert({Customer:'a',Name:"Mouse",Quantity:3,Price:200});
db.item.insert({Customer:'a',Name:"Keyboard",Quantity:5,Price:800});
> db.item.insert({Customer:'b',Name:"Mouse",Quantity:3,Price:500});
> db.item.insert({Customer:'a',Name:"Keyboard",Quantity:4,Price:2000});
> db.item.find().pretty();
{
"_id" : ObjectId("5d8f128237dc2e143b51bde5"),
"Customer" : "a",
"Name" : "Mouse",
"Quantity" : 3,
"Price" : 200
}
{
"_id" : ObjectId("5d8f12a637dc2e143b51bde6"),
"Customer" : "a",
"Name" : "Keyboard",
"Quantity" : 5,
"Price" : 800
}
{
"_id" : ObjectId("5d8f12be37dc2e143b51bde7"),
"Customer" : "b",
"Name" : "Mouse",
"Quantity" : 3,
"Price" : 500
}
{
"_id" : ObjectId("5d8f12da37dc2e143b51bde8"),
"Customer" : "a",
"Name" : "Keyboard",
"Quantity" : 4,
"Price" : 2000
}
> db.item.aggregate([{$group:{_id:"Name",total:{$sum:1}}}]);
{ "result" : [ { "_id" : "Name", "total" : 4 } ], "ok" : 1 }