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How to drop an index in MongoDB using Java?
In MongoDB to drop an index, you need to use dropIndex() method.
Syntax
db.COLLECTION_NAME.dropIndex({KEY:1})In Java, you can drop an Index using the dropIndex() method, to this method you need to pass the type of the index (ascending or descending) and the field name on which you have created it.
dropIndex(Indexes.ascending("name"));Example
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.model.Indexes;
import org.bson.Document;
import com.mongodb.MongoClient;
public class DroppingIndex {
public static void main( String args[] ) {
//Creating a MongoDB client
MongoClient mongo = new MongoClient( "localhost" , 27017 );
//Accessing the database
MongoDatabase database = mongo.getDatabase("myDatabase");
//Creating a collection
database.createCollection("sampleCollection");
//Retrieving the collection on which you want to create the index
MongoCollection coll = database.getCollection("sampleCollection");
//Creating indexes
coll.createIndex(Indexes.ascending("age"));
coll.createIndex(Indexes.ascending("name"));
System.out.println("List of colections: ");
for (Document index : coll.listIndexes()) {
System.out.println(index.toJson());
}
//Dropping the index
coll = database.getCollection("sampleCollection");
coll.dropIndex(Indexes.ascending("name"));
System.out.println("List of colections after deleting one ");
for (Document index : coll.listIndexes()) {
System.out.println(index.toJson());
}
}
}Output
List of colections:
{"v": 2, "key": {"_id": 1}, "name": "_id_", "ns": "myDatabase.sampleCollection"}
{"v": 2, "key": {"age": 1}, "name": "age_1", "ns": "myDatabase.sampleCollection"}
{"v": 2, "key": {"name": 1}, "name": "name_1", "ns":
"myDatabase.sampleCollection"}
List of colections after deleting one
{"v": 2, "key": {"_id": 1}, "name": "_id_", "ns": "myDatabase.sampleCollection"}
{"v": 2, "key": {"age": 1}, "name": "age_1", "ns": "myDatabase.sampleCollection"}
Updated on: 10-Apr-2020
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