In this tutorials, we will see how to delete documents from Solr using SolrJ.

Delete Documents from Solr:

In previous tutorials, we have seen how to add documents to Solr, now as part of this example, I am going to delete the documents from solr.

Technologies:

• Java 8
• Apache Solr 7.5.0
• Apache SolrJ 7.5.0
• Apache Http Core 4.4.6
• Apache Http Client 4.5.3
• Maven

Maven Dependency:

Add the below solrj dependency on your pom.xml, it will get all the necessary dependencies to connect with solr.

<dependency>
     <groupId>org.apache.solr</groupId>
     <artifactId>solr-solrj</artifactId>
     <version>7.5.0</version>
</dependency>

Prerequisites:

Install/setup the Solr instance and run on your machine, add some document to it. I have my Solr installed on windows 10 and added some documents.

Delete Documents from Solr:

SolrJ gave two different ways (methods) to delete the documents from Solr.

• Deleting by Query and
• Deleting by id

Deleting by Query:

deleteByQuery(“column: data”) method takes a string as a parameter and executed the same on running solr, then the matching documents will be deleted.

Here I am going to delete a document where item_name is equal to Spring in action.

deleteByQuery(“item_name:Spring in action”)

package com.onlinetutorilspoint.solr;

import org.apache.solr.client.solrj.SolrClient;
import org.apache.solr.client.solrj.SolrServerException;
import org.apache.solr.client.solrj.impl.HttpSolrClient;
import org.apache.solr.common.SolrInputDocument;

import java.io.IOException;

public class DeleteDocuments {
    public static void main(String args[]) throws SolrServerException, IOException {
        //Preparing the Solr client
        String SOLR_URL = "http://localhost:8983/solr/sample-items";
        SolrClient Solr = new HttpSolrClient.Builder(SOLR_URL).build();

        //Preparing the Solr document
        SolrInputDocument doc = new SolrInputDocument();

        //Deleting the document where item-name equal Spring in action
        Solr.deleteByQuery("item_name:Spring in action");
        Solr.commit();
        System.out.println("Documents deleted");
    }
}

Deleting by multiple conditions:

deleteByQuery(“category:Mobiles AND item_name:iPhoneX”)

package com.onlinetutorilspoint.solr;

import org.apache.solr.client.solrj.SolrClient;
import org.apache.solr.client.solrj.SolrServerException;
import org.apache.solr.client.solrj.impl.HttpSolrClient;
import org.apache.solr.common.SolrInputDocument;

import java.io.IOException;

public class DeleteDocuments {
    public static void main(String args[]) throws SolrServerException, IOException {
        //Preparing the Solr client
        String SOLR_URL = "http://localhost:8983/solr/sample-items";
        SolrClient Solr = new HttpSolrClient.Builder(SOLR_URL).build();

        //Preparing the Solr document
        SolrInputDocument doc = new SolrInputDocument();

        //Deleting the documents from Solr
        Solr.deleteByQuery("category:Mobiles AND item_name:iPhoneX");
        Solr.commit();
        System.out.println("Documents deleted");
    }
}

Run:

>javac DeleteDocuments.java
>java DeleteDocuments
Documents deleted

After executing the above two queries Solr instance:

Delete All documents at a time:

deleteByQuery(“*”)

//Preparing the Solr document
SolrInputDocument doc = new SolrInputDocument();
//Deleting all documents in Solr
Solr.deleteByQuery("*");
Solr.commit();

Delete Documents by Id:

deleteById(“documentId”)

//Preparing the Solr document
SolrInputDocument doc = new SolrInputDocument();
//Deleting Solr Document by Id
Solr.deleteById("b8cd5a15-bb4b-4c06-ad96-2c1bd09177ed");
Solr.commit();

References:

Add documents to Solr

SolrJ docs

Happy Learning 🙂