Indexes

Import restaurants collection

wget https://www.dropbox.com/s/bfi06m1fvemzj69/primer-dataset-small.json

mongoimport --uri "mongodb+srv://admatic:admatic123@admatic-cluster-7qyyr.mongodb.net/admatic-db" \
    --collection restaurants --drop --file primer-dataset-small.json

2019-02-25T16:23:06.163+0000    connected to: localhost
2019-02-25T16:23:06.323+0000    dropping: admatic-db.restaurants
2019-02-25T16:23:06.696+0000    imported 10 documents

Code

mkdir -p src/main/java/com/admatic/primer

vim src/main/java/com/admatic/primer/IndexesPrimer.java

package com.admatic.primer;

import com.mongodb.client.MongoClient;
import com.mongodb.client.MongoClients;
import com.mongodb.client.MongoDatabase;
import org.bson.Document;

import java.util.logging.Level;
import java.util.logging.Logger;


public class IndexesPrimer {

    private static void singleFieldIndex(MongoDatabase db) {
        db.getCollection("restaurants").createIndex(new Document("cuisine", 1));
    }

    private static void createCompoundIndex(MongoDatabase db) {
        db.getCollection("restaurants").createIndex(new Document("cuisine", 1).append("address.zipcode", -1));
    }

    public static void main(final String[] args) {
        Logger mongoLogger = Logger.getLogger("org.mongodb.driver");
        mongoLogger.setLevel(Level.SEVERE);

        MongoClient mongoClient;

        if (args.length == 0) {
            mongoClient = MongoClients.create();
        } else {
            mongoClient = MongoClients.create(args[0]);
        }

        MongoDatabase database = mongoClient.getDatabase("admatic-db");

        switch (args[1]) {
            case "0":
                System.out.println("singleFieldIndex");
                singleFieldIndex(database);
                break;
            case "1":
                System.out.println("createCompoundIndex");
                createCompoundIndex(database);
                break;

            default:
                System.out.println("Enter an option between 0 and 1");
        }

        mongoClient.close();
    }
}

Compile

mvn compile

Run

Single Field Index

db.getCollection("restaurants").createIndex(new Document("cuisine", 1))

mvn exec:java -Dexec.mainClass=com.admatic.primer.IndexesPrimer \
    -Dexec.args="mongodb+srv://admatic:admatic123@admatic-cluster-7qyyr.mongodb.net/test 0"

singleFieldIndex

Create Compound Index

db.getCollection("restaurants").createIndex(new Document("cuisine", 1).append("address.zipcode", -1))

mvn exec:java -Dexec.mainClass=com.admatic.primer.IndexesPrimer \
    -Dexec.args="mongodb+srv://admatic:admatic123@admatic-cluster-7qyyr.mongodb.net/test 1"

createCompoundIndex

Verify

mongo "mongodb+srv://admatic-cluster-7qyyr.mongodb.net/test" --username admatic

MongoDB shell version v4.0.6
Enter password:

Welcome to the MongoDB shell.
For interactive help, type "help".
For more comprehensive documentation, see
        http://docs.mongodb.org/
Questions? Try the support group
        http://groups.google.com/group/mongodb-user
MongoDB Enterprise Admatic-Cluster-shard-0:PRIMARY>

use admatic-db

switched to db admatic-db

db.restaurants.getIndexes()

[
  {
    "v": 2,
    "key": {
      "_id": 1
    },
    "name": "_id_",
    "ns": "admatic-db.restaurants"
  },
  {
    "v": 2,
    "key": {
      "cuisine": 1
    },
    "name": "cuisine_1",
    "ns": "admatic-db.restaurants"
  },
  {
    "v": 2,
    "key": {
      "cuisine": 1,
      "address.zipcode": -1
    },
    "name": "cuisine_1_address.zipcode_-1",
    "ns": "admatic-db.restaurants"
  }
]