MONGO DB Document Field Indexing


db.users.find({ name: "Rahul" })


Agar 1 lakh records hain, to MongoDB sabhi check karega 😓

db.users.createIndex({ name: 1 })


Ab wahi query bahut fast chalegi ⚡

db.users.createIndex({ age: 1 })


1 = Ascending
-1 = Descending

db.users.createIndex({ name: 1, age: -1 })

db.users.getIndexes()

db.users.dropIndex("age_1")

Index kyon zaroori hai?

✔ Query fast hoti hai
✔ Performance behtar hoti hai
✔ Large data handle karna aasaan hota hai

Isliye wahi field par index banao jo:

👉 Baar-baar search me aati ho
👉 where / find me use hoti ho

Lekin mera sawal ye hai ki agar 500 document me name hai aur maine name ko index kar diya to MongoDB kaise kaam karega?

{ name: "Rahul", age: 25 }
{ name: "Amit", age: 30 }
{ name: "Neha", age: 22 }
...
(500 records)


Ab aapne ye index bana diya:

db.users.createIndex({ name: 1 })


MongoDB alag se ek index table bana leta hai (internally B-Tree structure):

Kuch aisa:

Amit   → document address
Neha   → document address
Pooja  → document address
Rahul  → document address


Har name value ke saamne uska document location store ho jaata hai.

Ab jab aap query chalate ho:

db.users.find({ name: "Rahul" })

Bina Index:

MongoDB bolega:

😓 “Chalo 500 ke 500 documents check karte hain…”

Isko kehte hain Collection Scan

Index ke saath:

MongoDB bolega:

⚡ “Index table me Rahul dhoondo → address mila → seedha wahin jump”

Bas 2–3 steps me record mil gaya.

Isko kehte hain Index Scan

Aasaan bhaasha me:

Index banne ke baad MongoDB:

Poore 500 documents nahi dekhta

Pehle index table dekhta hai

Wahin se exact document location leta hai

Seedha data utha leta hai

Isi liye speed bahut badh jaati hai 🚀