Working with Tables Using the AWS SDK for Java Low-Level API

To create a table, you must provide the table name, its primary key, and the provisioned throughput values. For more information, see Specifying Read and Write Requirements for Tables. The following Java code snippet creates an example table that uses a numeric type attribute Id as its primary key.

The following are the steps to create a table using the Java low-level API.

The following Java code snippet demonstrates the preceding steps. The snippet creates a table (ProductCatalog) that uses Id as the primary key and set of provisioned throughput values. Depending on your application requirements, you can update the provisioned throughput values by using the updateTable method.

ArrayList<AttributeDefinition> attributeDefinitions= new ArrayList<AttributeDefinition>();
attributeDefinitions.add(new AttributeDefinition().withAttributeName("Id").withAttributeType("N"));
        
ArrayList<KeySchemaElement> ks = new ArrayList<KeySchemaElement>();
ks.add(new KeySchemaElement().withAttributeName("Id").withKeyType(KeyType.HASH));
  
ProvisionedThroughput provisionedThroughput = new ProvisionedThroughput()
    .withReadCapacityUnits(10L)
    .withWriteCapacityUnits(10L);
        
CreateTableRequest request = new CreateTableRequest()
    .withTableName(tableName)
    .withAttributeDefinitions(attributeDefinitions)
    .withKeySchema(ks)
    .withProvisionedThroughput(provisionedThroughput);
    
CreateTableResult result = client.createTable(request);

You must wait until Amazon DynamoDB creates the table and sets the table status to ACTIVE. The createTable request returns a CreateTableResult from which you can get the TableDescription property that provides the necessary table information.

TableDescription tableDescription = result.getTableDescription();

System.out.printf("%s: %s \t ReadCapacityUnits: %d \t WriteCapacityUnits: %d",
  tableDescription.getTableStatus(),
  tableDescription.getTableName(),
  tableDescription.getProvisionedThroughput().getReadCapacityUnits(),
  tableDescription.getProvisionedThroughput().getWriteCapacityUnits());

You can also call the describeTable method of the client to get table information at anytime.

TableDescription tableDescription = client.describeTable(
  new DescribeTableRequest().withTableName(tableName)).getTable();

You can update only the provisioned throughput values of an existing table. Depending on you application requirements, you might need to update these values.

The following are the steps to update a table using the Java low-level API.

The following Java code snippet demonstrates the preceding steps.

client = new AmazonDynamoDBClient(credentials);
String tableName = "ProductCatalog";

ProvisionedThroughput provisionedThroughput = new ProvisionedThroughput()
  .withReadCapacityUnits(15L)
  .withWriteCapacityUnits(12L);

UpdateTableRequest updateTableRequest = new UpdateTableRequest()
  .withTableName(tableName)
  .withProvisionedThroughput(provisionedThroughput);

UpdateTableResult result = client.updateTable(updateTableRequest);

The following are the steps to delete a table using the Java low-level API.

The following Java code snippet demonstrates the preceding steps.

client = new AmazonDynamoDBClient(credentials);
String tableName = "ProductCatalog";

DeleteTableRequest deleteTableRequest = new DeleteTableRequest()
  .withTableName(tableName);
DeleteTableResult result = client.deleteTable(deleteTableRequest);

To list tables in your account using the AWS SDK for Java low-level API, create an instance of the AmazonDynamoDBClient and execute the listTables method. The ListTables API requires no parameters. However, you can specify optional parameters. For example, you can set the limit parameter if you want to use paging to limit the number of table names per page. This requires you to create a ListTablesRequest object and provide optional parameters as shown in the following Java code snippet. Along with the page size, the request sets the exclusiveStartTableName parameter. Initially, exclusiveStartTableName is null, however, after fetching the first page of result, to retrieve the next page of result, you must set this parameter value to the lastEvaluatedTableName property of the current result.

client = new AmazonDynamoDBClient(credentials);

// Initial value for the first page of table names.
String lastEvaluatedTableName = null;
do {
    
    ListTablesRequest listTablesRequest = new ListTablesRequest()
    .withLimit(10)
    .withExclusiveStartTableName(lastEvaluatedTableName);
    
    ListTablesResult result = client.listTables(listTablesRequest);
    lastEvaluatedTableName = result.getLastEvaluatedTableName();
    
    for (String name : result.getTableNames()) {
        System.out.println(name);
    }
    
} while (lastEvaluatedTableName != null);