Mongodb avoid duplicate entries

Question

I am newbie to mongodb. May I know how to avoid duplicate entries. In relational tables, we use primary key to avoid it. May I know how to specify it in Mongodb using java?<

Answer 1

using pymongo it looks like:

mycol.create_index("id", unique=True)

where myCol is the collection in the DB

#!/usr/bin/env python
# -*- coding: utf-8 -*-
import pymongo

myclient = pymongo.MongoClient("mongodb://localhost:27017/")
mydb = myclient["mydatabase"]
mycol = mydb["customers"]
mycol.create_index("id", unique=True)
mydict = {"name": "xoce", "address": "Highway to hell 666", "id": 1}
x = mycol.insert_one(mydict)