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How to delete a MongoDB document using Java?
You can delete a document from an existing collection in MongoDB using the remove() method.
Syntax
db.coll.remove(DELLETION_CRITTERIA)
Where,
db is the database.
coll is the collection (name) in which you want to insert the document
Example
Assume we have a collection named students in the MongoDB database with the following documents −
{name:"Ram", age:26, city:"Mumbai"}
{name:"Roja", age:28, city:"Hyderabad"}
{name:"Ramani", age:35, city:"Delhi"}The following query deletes the document with name value as Ram.
> db.test.remove({'name': 'Ram'})
WriteResult({ "nRemoved" : 1 })
> db.test.find()
{ "_id" : ObjectId("5e8700"), "name" : "Roja", "age" : 28, "city" : "Hyderabad" }
{ "_id" : ObjectId("5e4161"), "name" : "Ramani", "age" : 35, "city" : "Delhi" }
{ "_id" : ObjectId("5e8161"), "name" : "Ramani", "age" : 35, "city" : "Delhi" }Using Java program
In Java, you delete a document from a collection using the in the current collection using the deleteOne() method of the com.mongodb.client.MongoCollection interface.
Therefore to create a collection in MongoDB using Java program −
Make sure you have installed MongoDB in your system
Add the following dependency to its pom.xml file of your Java project.
<dependency> <groupId>org.mongodb</groupId> <artifactId>mongo-java-driver</artifactId> <version>3.12.2</version> </dependency>
Create a MongoDB client by instantiating the MongoClient class.
Connect to a database using the getDatabase() method.
Get the object of the collection from which you want to delete the document, using the getCollection() method.
Delete the required document invoking the deleteOne() method.
Example
Assume we have a collection named students in the MongoDB database with the following documents −
{name:"Ram", age:26, city:"Mumbai"}
{name:"Roja", age:28, city:"Hyderabad"}
{name:"Ramani", age:35, city:"Delhi"}Following Java program deletes a document from this collection and displays the remaining −
import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.model.Filters;
import java.util.Iterator;
import org.bson.Document;
import com.mongodb.MongoClient;
public class DeletingDocuments {
public static void main( String args[] ) {
//Creating a MongoDB client
MongoClient mongo = new MongoClient( "localhost" , 27017 );
//Connecting to the database
MongoDatabase database = mongo.getDatabase("myDatabase");
//Creating a collection
MongoCollection<Document> collection = database.getCollection("students");
//Deleting a document
collection.deleteOne(Filters.eq("name", "Ram"));
System.out.println("Document deleted successfully...");
//Retrieving the documents after the delete operation
FindIterable<Document> iterDoc = collection.find();
int i = 1;
System.out.println("Remaining documents:");
Iterator it = iterDoc.iterator();
while (it.hasNext()) {
System.out.println(it.next());
i++;
}
}
}Output
Document deleted successfully...
Remaining documents:
Document{{_id=5e871141a89ad86b7b8ad229, name=Robert, age=27, city=Vishakhapatnam}}
Document{{_id=5e871141a89ad86b7b8ad22a, name=Rhim, age=30, city=Delhi}}
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