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Program to Delete all Documents From Collection In MongoDb in java >

Program to Delete all Documents From Collection In MongoDb in java >

package deleteDocumentFromCollectionInMongoDb;

/**

* Write a program to Delete all Documents From Collection In MongoDb in java

import com.mongodb.BasicDBObject;

import com.mongodb.DB;

import com.mongodb.DBCollection;

import com.mongodb.DBCursor;

import com.mongodb.MongoClient;

import com.mongodb.MongoClientURI;

import com.mongodb.WriteResult;

public class DeleteDocumentFromCollectionInMongoDb3_AllDocumentsInCollection {

public static void main(String[] args) {

/* Connect to MongoDB */

MongoClient mongoClient =

new MongoClient(new MongoClientURI("mongodb://localhost:27017"));

/* Connect to DATABASE */

//If in case database doesn't exists, it will be created at runtime

DB db = mongoClient.getDB("mydb");

/* Get the COLLECTION (TABLE) */

//If in case collection (Table) doesn't exists, it will be created at runtime

DBCollection dbCollection = db.getCollection("Employee");

/*If collection already exists, you may remove everything

from collection for perfect OUTPUT of program*/

//dbCollection.remove(new BasicDBObject()); //Not Mandatory

/* create a BasicDBObject (document /record) */

BasicDBObject basicDBObject1 = new BasicDBObject();

basicDBObject1.put("id", 1);

basicDBObject1.put("name", "Ankit");

/* Insert document/record in COLLECTION in MongoDB */

dbCollection.insert(basicDBObject1);

/* create a BasicDBObject (document /record) */

BasicDBObject basicDBObject2 = new BasicDBObject();

basicDBObject2.put("id", 2);

basicDBObject2.put("name", "Sam");

/* Insert document/record in collection in MongoDB */

dbCollection.insert(basicDBObject2);

/* Display documents of collection before DELETE in MongoDB */

System.out.println("Display documents of collection before DELETE in MongoDB");

DBCursor cursor0 = dbCollection.find();

while (cursor0.hasNext()) {

System.out.println(cursor0.next());

}

/** At this stage Employee collection looks like this >

{ "_id" : { "$oid" : "585547bbad8dc81b4c7c8144"} , "id" : 1 , "name" : "Ankit"}

{ "_id" : { "$oid" : "585547bbad8dc81b4c7c8145"} , "id" : 2 , "name" : "Sam"}

/** Now, let's DELETE All Documents In Collection */

/** Execute DELETE/REMOVE query - To DELETE ALL DOCUMENTs in collection in MongoDB */

//remove method delete documents from a collection.

WriteResult deleteResult =
dbCollection.remove(new BasicDBObject());

System.out.println("\nExecute DELETE/REMOVE query- To DELETE ALL DOCUMENTs in collection");

System.out.println("No of documents deleted = " + deleteResult.getN());

System.out.println("All documents have been DELETED");

}

/* OUTPUT

Display documents of collection before DELETE in MongoDB

{ "_id" : { "$oid" : "585547bbad8dc81b4c7c8144"} , "id" : 1 , "name" : "Ankit"}

{ "_id" : { "$oid" : "585547bbad8dc81b4c7c8145"} , "id" : 2 , "name" : "Sam"}

Execute DELETE/REMOVE query- To DELETE ALL DOCUMENTs in collection

No of documents deleted = 2

All documents have been DELETED

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Summary -

So in this MongoDB tutorial we learned with example and program how to to Delete all Documents From Collection In MongoDb in java.

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