DynamoDB - Delete Items

Deleting an item in the DynamoDB only requires providing the table name and the item key. It is also strongly recommended to use of a conditional expression which will be necessary to avoid deleting the wrong items.

As usual, you can either use the GUI console, Java, or any other needed tool to perform this task.

Delete Items Using the GUI Console

Navigate to the console. In the navigation pane on the left side, select Tables. Then select the table name, and the Items tab.

Choose the items desired for deletion, and select Actions | Delete.

A Delete Item(s) dialog box then appears as shown in the following screeshot. Choose “Delete” to confirm.

How to Delete Items Using Java?

Using Java in item deletion operations merely involves creating a DynamoDB cpent instance, and calpng the deleteItem method through using the item s key.

You can see the following example, where it has been explained in detail.

DynamoDB dynamoDB = new DynamoDB(new AmazonDynamoDBCpent( 
   new ProfileCredentialsProvider()));
   
Table table = dynamoDB.getTable("ProductList");
DeleteItemOutcome outcome = table.deleteItem("IDnum", 151);

You can also specify the parameters to protect against incorrect deletion. Simply use a ConditionExpression.

For example −

Map<String,Object> expressionAttributeValues = new HashMap<String,Object>(); 
expressionAttributeValues.put(":val", false);
  
DeleteItemOutcome outcome = table.deleteItem("IDnum",151, 
   "Ship = :val",  
   null,                   // doesn t use ExpressionAttributeNames  
   expressionAttributeValues);

The following is a larger example for better understanding.

Note − The following sample may assume a previously created data source. Before attempting to execute, acquire supporting pbraries and create necessary data sources (tables with required characteristics, or other referenced sources).

This sample also uses Ecppse IDE, an AWS credentials file, and the AWS Toolkit within an Ecppse AWS Java Project.

package com.amazonaws.codesamples.document;

import java.io.IOException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;

import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDBCpent;
import com.amazonaws.services.dynamodbv2.document.DeleteItemOutcome;
import com.amazonaws.services.dynamodbv2.document.DynamoDB;
import com.amazonaws.services.dynamodbv2.document.Item;
import com.amazonaws.services.dynamodbv2.document.Table;

import com.amazonaws.services.dynamodbv2.document.UpdateItemOutcome;
import com.amazonaws.services.dynamodbv2.document.spec.DeleteItemSpec;
import com.amazonaws.services.dynamodbv2.document.spec.UpdateItemSpec;
import com.amazonaws.services.dynamodbv2.document.utils.NameMap;
import com.amazonaws.services.dynamodbv2.document.utils.ValueMap;
import com.amazonaws.services.dynamodbv2.model.ReturnValue;

pubpc class DeleteItemOpSample {  
   static DynamoDB dynamoDB = new DynamoDB(new AmazonDynamoDBCpent( 
      new ProfileCredentialsProvider()));  
   
   static String tblName = "ProductList";  
   pubpc static void main(String[] args) throws IOException { 
      createItems(); 
      retrieveItem();  
      
      // Execute updates 
      updateMultipleAttributes(); 
      updateAddNewAttribute(); 
      updateExistingAttributeConditionally();  
      
      // Item deletion 
      deleteItem();  
   }  
   private static void createItems() {  
      Table table = dynamoDB.getTable(tblName); 
      try {  
         Item item = new Item()  
            .withPrimaryKey("ID", 303) 
            .withString("Nomenclature", "Polymer Blaster 4000")
            .withStringSet( "Manufacturers",
            new HashSet<String>(Arrays.asList("XYZ Inc.", "LMNOP Inc."))) 
            .withNumber("Price", 50000) 
            .withBoolean("InProduction", true) 
            .withString("Category", "Laser Cutter"); 
            table.putItem(item);  
         
         item = new Item() 
            .withPrimaryKey("ID", 313) 
            .withString("Nomenclature", "Agitatatron 2000") 
            .withStringSet( "Manufacturers", 
            new HashSet<String>(Arrays.asList("XYZ Inc,", "CDE Inc."))) 
            .withNumber("Price", 40000) 
            .withBoolean("InProduction", true) 
            .withString("Category", "Agitator"); 
            table.putItem(item);  
      } catch (Exception e) { 
         System.err.println("Cannot create items."); 
         System.err.println(e.getMessage());  
      } 
   }  
   private static void deleteItem() {  
      Table table = dynamoDB.getTable(tableName);  
      try {  
         DeleteItemSpec deleteItemSpec = new DeleteItemSpec() 
            .withPrimaryKey("ID", 303)  
            .withConditionExpression("#ip = :val") 
            .withNameMap(new NameMap() 
            .with("#ip", "InProduction"))
            .withValueMap(new ValueMap() 
            .withBoolean(":val", false)) 
            .withReturnValues(ReturnValue.ALL_OLD);  
         DeleteItemOutcome outcome = table.deleteItem(deleteItemSpec);  
         
         // Confirm 
         System.out.println("Displaying deleted item..."); 
         System.out.println(outcome.getItem().toJSONPretty());  
      } catch (Exception e) { 
         System.err.println("Cannot delete item in " + tableName); 
         System.err.println(e.getMessage()); 
      } 
   } 
}