DynamoDBClient Class

Member Function Documentation

DynamoDBClient::DynamoDBClient(const QtAws::Core::AwsRegion::Region region = QtAws::Core::AwsRegion::InvalidRegion, QtAws::Core::AwsAbstractCredentials *credentials = NULL, QNetworkAccessManager * const manager = NULL, QObject * const parent = 0)

Constructs a DynamoDBClient object.

The new client object will region, credentials, and manager for network operations.

The new object will be owned by parent, if set.

DynamoDBClient::DynamoDBClient(const QUrl &endpoint, QtAws::Core::AwsAbstractCredentials *credentials = NULL, QNetworkAccessManager * const manager = NULL, QObject * const parent = 0)

This function overloads DynamoDBClient().

This overload allows the caller to specify the specific endpoint to send requests to. Typically, it is easier to use the alternative constructor, which allows the caller to specify an AWS region instead, in which case this client will determine the correct endpoint for the given region automatically (via AwsEndpoint::getEndpoint).

See also QtAws::Core::AwsEndpoint::getEndpoint.

[slot] BatchGetItemResponse *DynamoDBClient::batchGetItem(const BatchGetItemRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an BatchGetItemResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

The <code>BatchGetItem</code> operation returns the attributes of one or more items from one or more tables. You identify requested items by primary

key>

A single operation can retrieve up to 16 MB of data, which can contain as many as 100 items. <code>BatchGetItem</code> will return a partial result if the response size limit is exceeded, the table's provisioned throughput is exceeded, or an internal processing failure occurs. If a partial result is returned, the operation returns a value for <code>UnprocessedKeys</code>. You can use this value to retry the operation starting with the next item to

get> <b>

If you request more than 100 items <code>BatchGetItem</code> will return a <code>ValidationException</code> with the message "Too many items requested for the BatchGetItem

call"> </b>

For example, if you ask to retrieve 100 items, but each individual item is 300 KB in size, the system returns 52 items (so as not to exceed the 16 MB limit). It also returns an appropriate <code>UnprocessedKeys</code> value so you can get the next page of results. If desired, your application can include its own logic to assemble the pages of results into one data

set>

If <i>none</i> of the items can be processed due to insufficient provisioned throughput on all of the tables in the request, then <code>BatchGetItem</code> will return a <code>ProvisionedThroughputExceededException</code>. If <i>at least one</i> of the items is successfully processed, then <code>BatchGetItem</code> completes successfully, while returning the keys of the unread items in

<code>UnprocessedKeys</code>> <b>

If DynamoDB returns any unprocessed items, you should retry the batch operation on those items. However, <i>we strongly recommend that you use an exponential backoff algorithm</i>. If you retry the batch operation immediately, the underlying read or write requests can still fail due to throttling on the individual tables. If you delay the batch operation using exponential backoff, the individual requests in the batch are much more likely to

succeed>

For more information, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ErrorHandling.html#BatchOperations">Batch Operations and Error Handling</a> in the <i>Amazon DynamoDB Developer

Guide</i>> </b>

By default, <code>BatchGetItem</code> performs eventually consistent reads on every table in the request. If you want strongly consistent reads instead, you can set <code>ConsistentRead</code> to <code>true</code> for any or all

tables>

In order to minimize response latency, <code>BatchGetItem</code> retrieves items in

parallel>

When designing your application, keep in mind that DynamoDB does not return items in any particular order. To help parse the response by item, include the primary key values for the items in your request in the <code>ProjectionExpression</code>

parameter>

If a requested item does not exist, it is not returned in the result. Requests for nonexistent items consume the minimum read capacity units according to the type of read. For more information, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/WorkingWithTables.html#CapacityUnitCalculations">Capacity Units Calculations</a> in the <i>Amazon DynamoDB Developer

[slot] BatchWriteItemResponse *DynamoDBClient::batchWriteItem(const BatchWriteItemRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an BatchWriteItemResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

The <code>BatchWriteItem</code> operation puts or deletes multiple items in one or more tables. A single call to <code>BatchWriteItem</code> can write up to 16 MB of data, which can comprise as many as 25 put or delete requests. Individual items to be written can be as large as 400

KB> <note>

<code>BatchWriteItem</code> cannot update items. To update items, use the <code>UpdateItem</code>

action> </note>

The individual <code>PutItem</code> and <code>DeleteItem</code> operations specified in <code>BatchWriteItem</code> are atomic; however <code>BatchWriteItem</code> as a whole is not. If any requested operations fail because the table's provisioned throughput is exceeded or an internal processing failure occurs, the failed operations are returned in the <code>UnprocessedItems</code> response parameter. You can investigate and optionally resend the requests. Typically, you would call <code>BatchWriteItem</code> in a loop. Each iteration would check for unprocessed items and submit a new <code>BatchWriteItem</code> request with those unprocessed items until all items have been

processed>

Note that if <i>none</i> of the items can be processed due to insufficient provisioned throughput on all of the tables in the request, then <code>BatchWriteItem</code> will return a

<code>ProvisionedThroughputExceededException</code>> <b>

If DynamoDB returns any unprocessed items, you should retry the batch operation on those items. However, <i>we strongly recommend that you use an exponential backoff algorithm</i>. If you retry the batch operation immediately, the underlying read or write requests can still fail due to throttling on the individual tables. If you delay the batch operation using exponential backoff, the individual requests in the batch are much more likely to

succeed>

For more information, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ErrorHandling.html#BatchOperations">Batch Operations and Error Handling</a> in the <i>Amazon DynamoDB Developer

Guide</i>> </b>

With <code>BatchWriteItem</code>, you can efficiently write or delete large amounts of data, such as from Amazon Elastic MapReduce (EMR), or copy data from another database into DynamoDB. In order to improve performance with these large-scale operations, <code>BatchWriteItem</code> does not behave in the same way as individual <code>PutItem</code> and <code>DeleteItem</code> calls would. For example, you cannot specify conditions on individual put and delete requests, and <code>BatchWriteItem</code> does not return deleted items in the

response>

If you use a programming language that supports concurrency, you can use threads to write items in parallel. Your application must include the necessary logic to manage the threads. With languages that don't support threading, you must update or delete the specified items one at a time. In both situations, <code>BatchWriteItem</code> performs the specified put and delete operations in parallel, giving you the power of the thread pool approach without having to introduce complexity into your

application>

Parallel processing reduces latency, but each specified put and delete request consumes the same number of write capacity units whether it is processed in parallel or not. Delete operations on nonexistent items consume one write capacity

unit>

If one or more of the following is true, DynamoDB rejects the entire batch write

operation> <ul> <li>

One or more tables specified in the <code>BatchWriteItem</code> request does not

exist> </li> <li>

Primary key attributes specified on an item in the request do not match those in the corresponding table's primary key

schema> </li> <li>

You try to perform multiple operations on the same item in the same <code>BatchWriteItem</code> request. For example, you cannot put and delete the same item in the same <code>BatchWriteItem</code> request.

</p </li> <li>

Your request contains at least two items with identical hash and range keys (which essentially is two put operations).

</p </li> <li>

There are more than 25 requests in the

batch> </li> <li>

Any individual item in a batch exceeds 400

KB> </li> <li>

The total request size exceeds 16

[slot] CreateBackupResponse *DynamoDBClient::createBackup(const CreateBackupRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an CreateBackupResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Creates a backup for an existing

table>

Each time you create an On-Demand Backup, the entire table data is backed up. There is no limit to the number of on-demand backups that can be taken.

</p

When you create an On-Demand Backup, a time marker of the request is cataloged, and the backup is created asynchronously, by applying all changes until the time of the request to the last full table snapshot. Backup requests are processed instantaneously and become available for restore within minutes.

</p

You can call <code>CreateBackup</code> at a maximum rate of 50 times per

second>

All backups in DynamoDB work without consuming any provisioned throughput on the

table>

If you submit a backup request on 2018-12-14 at 14:25:00, the backup is guaranteed to contain all data committed to the table up to 14:24:00, and data committed after 14:26:00 will not be. The backup may or may not contain data modifications made between 14:24:00 and 14:26:00. On-Demand Backup does not support causal consistency.

</p

Along with data, the following are also included on the backups:

</p <ul> <li>

Global secondary indexes

(GSIs> </li> <li>

Local secondary indexes

(LSIs> </li> <li>

Stream> </li> <li>

Provisioned read and write

[slot] CreateGlobalTableResponse *DynamoDBClient::createGlobalTable(const CreateGlobalTableRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an CreateGlobalTableResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Creates a global table from an existing table. A global table creates a replication relationship between two or more DynamoDB tables with the same table name in the provided regions.

</p

Tables can only be added as the replicas of a global table group under the following conditions:

</p <ul> <li>

The tables must have the same name.

</p </li> <li>

The tables must contain no items.

</p </li> <li>

The tables must have the same hash key and sort key (if present).

</p </li> <li>

The tables must have DynamoDB Streams enabled (NEW_AND_OLD_IMAGES).

</p </li> <li>

The tables must have same provisioned and maximum write capacity units.

</p </li> </ul>

If global secondary indexes are specified, then the following conditions must also be met:

</p <ul> <li>

The global secondary indexes must have the same name.

</p </li> <li>

The global secondary indexes must have the same hash key and sort key (if present).

</p </li> <li>

The global secondary indexes must have the same provisioned and maximum write capacity units.

[slot] CreateTableResponse *DynamoDBClient::createTable(const CreateTableRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an CreateTableResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

The <code>CreateTable</code> operation adds a new table to your account. In an AWS account, table names must be unique within each region. That is, you can have two tables with same name if you create the tables in different

regions>

<code>CreateTable</code> is an asynchronous operation. Upon receiving a <code>CreateTable</code> request, DynamoDB immediately returns a response with a <code>TableStatus</code> of <code>CREATING</code>. After the table is created, DynamoDB sets the <code>TableStatus</code> to <code>ACTIVE</code>. You can perform read and write operations only on an <code>ACTIVE</code> table.

</p

You can optionally define secondary indexes on the new table, as part of the <code>CreateTable</code> operation. If you want to create multiple tables with secondary indexes on them, you must create the tables sequentially. Only one table with secondary indexes can be in the <code>CREATING</code> state at any given

time>

You can use the <code>DescribeTable</code> action to check the table

[slot] DeleteBackupResponse *DynamoDBClient::deleteBackup(const DeleteBackupRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an DeleteBackupResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Deletes an existing backup of a

table>

You can call <code>DeleteBackup</code> at a maximum rate of 10 times per

[slot] DeleteItemResponse *DynamoDBClient::deleteItem(const DeleteItemRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an DeleteItemResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Deletes a single item in a table by primary key. You can perform a conditional delete operation that deletes the item if it exists, or if it has an expected attribute

value>

In addition to deleting an item, you can also return the item's attribute values in the same operation, using the <code>ReturnValues</code>

parameter>

Unless you specify conditions, the <code>DeleteItem</code> is an idempotent operation; running it multiple times on the same item or attribute does <i>not</i> result in an error

response>

Conditional deletes are useful for deleting items only if specific conditions are met. If those conditions are met, DynamoDB performs the delete. Otherwise, the item is not

[slot] DeleteTableResponse *DynamoDBClient::deleteTable(const DeleteTableRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an DeleteTableResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

The <code>DeleteTable</code> operation deletes a table and all of its items. After a <code>DeleteTable</code> request, the specified table is in the <code>DELETING</code> state until DynamoDB completes the deletion. If the table is in the <code>ACTIVE</code> state, you can delete it. If a table is in <code>CREATING</code> or <code>UPDATING</code> states, then DynamoDB returns a <code>ResourceInUseException</code>. If the specified table does not exist, DynamoDB returns a <code>ResourceNotFoundException</code>. If table is already in the <code>DELETING</code> state, no error is returned.

</p <note>

DynamoDB might continue to accept data read and write operations, such as <code>GetItem</code> and <code>PutItem</code>, on a table in the <code>DELETING</code> state until the table deletion is

complete> </note>

When you delete a table, any indexes on that table are also

deleted>

If you have DynamoDB Streams enabled on the table, then the corresponding stream on that table goes into the <code>DISABLED</code> state, and the stream is automatically deleted after 24

hours>

Use the <code>DescribeTable</code> action to check the status of the table.

[slot] DescribeBackupResponse *DynamoDBClient::describeBackup(const DescribeBackupRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an DescribeBackupResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Describes an existing backup of a

table>

You can call <code>DescribeBackup</code> at a maximum rate of 10 times per

[slot] DescribeContinuousBackupsResponse *DynamoDBClient::describeContinuousBackups(const DescribeContinuousBackupsRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an DescribeContinuousBackupsResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Checks the status of continuous backups and point in time recovery on the specified table. Continuous backups are <code>ENABLED</code> on all tables at table creation. If point in time recovery is enabled, <code>PointInTimeRecoveryStatus</code> will be set to

ENABLED>

Once continuous backups and point in time recovery are enabled, you can restore to any point in time within <code>EarliestRestorableDateTime</code> and <code>LatestRestorableDateTime</code>.

</p

<code>LatestRestorableDateTime</code> is typically 5 minutes before the current time. You can restore your table to any point in time during the last 35 days.

</p

You can call <code>DescribeContinuousBackups</code> at a maximum rate of 10 times per

[slot] DescribeGlobalTableResponse *DynamoDBClient::describeGlobalTable(const DescribeGlobalTableRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an DescribeGlobalTableResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Returns information about the specified global

[slot] DescribeGlobalTableSettingsResponse *DynamoDBClient::describeGlobalTableSettings(const DescribeGlobalTableSettingsRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an DescribeGlobalTableSettingsResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Describes region specific settings for a global

[slot] DescribeLimitsResponse *DynamoDBClient::describeLimits(const DescribeLimitsRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an DescribeLimitsResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Returns the current provisioned-capacity limits for your AWS account in a region, both for the region as a whole and for any one DynamoDB table that you create

there>

When you establish an AWS account, the account has initial limits on the maximum read capacity units and write capacity units that you can provision across all of your DynamoDB tables in a given region. Also, there are per-table limits that apply when you create a table there. For more information, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Limits.html">Limits</a> page in the <i>Amazon DynamoDB Developer

Guide</i>>

Although you can increase these limits by filing a case at <a href="https://console.aws.amazon.com/support/home#/">AWS Support Center</a>, obtaining the increase is not instantaneous. The <code>DescribeLimits</code> action lets you write code to compare the capacity you are currently using to those limits imposed by your account so that you have enough time to apply for an increase before you hit a

limit>

For example, you could use one of the AWS SDKs to do the

following> <ol> <li>

Call <code>DescribeLimits</code> for a particular region to obtain your current account limits on provisioned capacity

there> </li> <li>

Create a variable to hold the aggregate read capacity units provisioned for all your tables in that region, and one to hold the aggregate write capacity units. Zero them

both> </li> <li>

Call <code>ListTables</code> to obtain a list of all your DynamoDB

tables> </li> <li>

For each table name listed by <code>ListTables</code>, do the

following> <ul> <li>

Call <code>DescribeTable</code> with the table

name> </li> <li>

Use the data returned by <code>DescribeTable</code> to add the read capacity units and write capacity units provisioned for the table itself to your

variables> </li> <li>

If the table has one or more global secondary indexes (GSIs), loop over these GSIs and add their provisioned capacity values to your variables as

well> </li> </ul> </li> <li>

Report the account limits for that region returned by <code>DescribeLimits</code>, along with the total current provisioned capacity levels you have

calculated> </li> </ol>

This will let you see whether you are getting close to your account-level

limits>

The per-table limits apply only when you are creating a new table. They restrict the sum of the provisioned capacity of the new table itself and all its global secondary

indexes>

For existing tables and their GSIs, DynamoDB will not let you increase provisioned capacity extremely rapidly, but the only upper limit that applies is that the aggregate provisioned capacity over all your tables and GSIs cannot exceed either of the per-account

limits> <note>

<code>DescribeLimits</code> should only be called periodically. You can expect throttling errors if you call it more than once in a

minute> </note>

The <code>DescribeLimits</code> Request element has no

[slot] DescribeTableResponse *DynamoDBClient::describeTable(const DescribeTableRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an DescribeTableResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Returns information about the table, including the current status of the table, when it was created, the primary key schema, and any indexes on the

table> <note>

If you issue a <code>DescribeTable</code> request immediately after a <code>CreateTable</code> request, DynamoDB might return a <code>ResourceNotFoundException</code>. This is because <code>DescribeTable</code> uses an eventually consistent query, and the metadata for your table might not be available at that moment. Wait for a few seconds, and then try the <code>DescribeTable</code> request

[slot] DescribeTimeToLiveResponse *DynamoDBClient::describeTimeToLive(const DescribeTimeToLiveRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an DescribeTimeToLiveResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Gives a description of the Time to Live (TTL) status on the specified table.

[slot] GetItemResponse *DynamoDBClient::getItem(const GetItemRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an GetItemResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

The <code>GetItem</code> operation returns a set of attributes for the item with the given primary key. If there is no matching item, <code>GetItem</code> does not return any data and there will be no <code>Item</code> element in the

response>

<code>GetItem</code> provides an eventually consistent read by default. If your application requires a strongly consistent read, set <code>ConsistentRead</code> to <code>true</code>. Although a strongly consistent read might take more time than an eventually consistent read, it always returns the last updated

[slot] ListBackupsResponse *DynamoDBClient::listBackups(const ListBackupsRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an ListBackupsResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

List backups associated with an AWS account. To list backups for a given table, specify <code>TableName</code>. <code>ListBackups</code> returns a paginated list of results with at most 1MB worth of items in a page. You can also specify a limit for the maximum number of entries to be returned in a page.

</p

In the request, start time is inclusive but end time is exclusive. Note that these limits are for the time at which the original backup was

requested>

You can call <code>ListBackups</code> a maximum of 5 times per

[slot] ListGlobalTablesResponse *DynamoDBClient::listGlobalTables(const ListGlobalTablesRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an ListGlobalTablesResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Lists all global tables that have a replica in the specified

[slot] ListTablesResponse *DynamoDBClient::listTables(const ListTablesRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an ListTablesResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Returns an array of table names associated with the current account and endpoint. The output from <code>ListTables</code> is paginated, with each page returning a maximum of 100 table

[slot] ListTagsOfResourceResponse *DynamoDBClient::listTagsOfResource(const ListTagsOfResourceRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an ListTagsOfResourceResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

List all tags on an Amazon DynamoDB resource. You can call ListTagsOfResource up to 10 times per second, per

account>

For an overview on tagging DynamoDB resources, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Tagging.html">Tagging for DynamoDB</a> in the <i>Amazon DynamoDB Developer

[slot] PutItemResponse *DynamoDBClient::putItem(const PutItemRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an PutItemResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Creates a new item, or replaces an old item with a new item. If an item that has the same primary key as the new item already exists in the specified table, the new item completely replaces the existing item. You can perform a conditional put operation (add a new item if one with the specified primary key doesn't exist), or replace an existing item if it has certain attribute values. You can return the item's attribute values in the same operation, using the <code>ReturnValues</code>

parameter> <b>

This topic provides general information about the <code>PutItem</code>

API>

For information on how to call the <code>PutItem</code> API using the AWS SDK in specific languages, see the

following> <ul> <li>

<a href="http://docs.aws.amazon.com/goto/aws-cli/dynamodb-2012-08-10/PutItem"> PutItem in the AWS Command Line Interface </a>

</p </li> <li>

<a href="http://docs.aws.amazon.com/goto/DotNetSDKV3/dynamodb-2012-08-10/PutItem"> PutItem in the AWS SDK for .NET </a>

</p </li> <li>

<a href="http://docs.aws.amazon.com/goto/SdkForCpp/dynamodb-2012-08-10/PutItem"> PutItem in the AWS SDK for C++ </a>

</p </li> <li>

<a href="http://docs.aws.amazon.com/goto/SdkForGoV1/dynamodb-2012-08-10/PutItem"> PutItem in the AWS SDK for Go </a>

</p </li> <li>

<a href="http://docs.aws.amazon.com/goto/SdkForJava/dynamodb-2012-08-10/PutItem"> PutItem in the AWS SDK for Java </a>

</p </li> <li>

<a href="http://docs.aws.amazon.com/goto/AWSJavaScriptSDK/dynamodb-2012-08-10/PutItem"> PutItem in the AWS SDK for JavaScript </a>

</p </li> <li>

<a href="http://docs.aws.amazon.com/goto/SdkForPHPV3/dynamodb-2012-08-10/PutItem"> PutItem in the AWS SDK for PHP V3 </a>

</p </li> <li>

<a href="http://docs.aws.amazon.com/goto/boto3/dynamodb-2012-08-10/PutItem"> PutItem in the AWS SDK for Python </a>

</p </li> <li>

<a href="http://docs.aws.amazon.com/goto/SdkForRubyV2/dynamodb-2012-08-10/PutItem"> PutItem in the AWS SDK for Ruby V2 </a>

</p </li> </ul> </b>

When you add an item, the primary key attribute(s) are the only required attributes. Attribute values cannot be null. String and Binary type attributes must have lengths greater than zero. Set type attributes cannot be empty. Requests with empty values will be rejected with a <code>ValidationException</code>

exception> <note>

To prevent a new item from replacing an existing item, use a conditional expression that contains the <code>attribute_not_exists</code> function with the name of the attribute being used as the partition key for the table. Since every record must contain that attribute, the <code>attribute_not_exists</code> function will only succeed if no matching item

exists> </note>

For more information about <code>PutItem</code>, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/WorkingWithItems.html">Working with Items</a> in the <i>Amazon DynamoDB Developer

[slot] QueryResponse *DynamoDBClient::query(const QueryRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an QueryResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

The <code>Query</code> operation finds items based on primary key values. You can query any table or secondary index that has a composite primary key (a partition key and a sort key).

</p

Use the <code>KeyConditionExpression</code> parameter to provide a specific value for the partition key. The <code>Query</code> operation will return all of the items from the table or index with that partition key value. You can optionally narrow the scope of the <code>Query</code> operation by specifying a sort key value and a comparison operator in <code>KeyConditionExpression</code>. To further refine the <code>Query</code> results, you can optionally provide a <code>FilterExpression</code>. A <code>FilterExpression</code> determines which items within the results should be returned to you. All of the other results are discarded.

</p

A <code>Query</code> operation always returns a result set. If no matching items are found, the result set will be empty. Queries that do not return results consume the minimum number of read capacity units for that type of read operation.

</p <note>

DynamoDB calculates the number of read capacity units consumed based on item size, not on the amount of data that is returned to an application. The number of capacity units consumed will be the same whether you request all of the attributes (the default behavior) or just some of them (using a projection expression). The number will also be the same whether or not you use a <code>FilterExpression</code>.

</p </note>

<code>Query</code> results are always sorted by the sort key value. If the data type of the sort key is Number, the results are returned in numeric order; otherwise, the results are returned in order of UTF-8 bytes. By default, the sort order is ascending. To reverse the order, set the <code>ScanIndexForward</code> parameter to false.

</p

A single <code>Query</code> operation will read up to the maximum number of items set (if using the <code>Limit</code> parameter) or a maximum of 1 MB of data and then apply any filtering to the results using <code>FilterExpression</code>. If <code>LastEvaluatedKey</code> is present in the response, you will need to paginate the result set. For more information, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Query.html#Query.Pagination">Paginating the Results</a> in the <i>Amazon DynamoDB Developer Guide</i>.

</p

<code>FilterExpression</code> is applied after a <code>Query</code> finishes, but before the results are returned. A <code>FilterExpression</code> cannot contain partition key or sort key attributes. You need to specify those attributes in the <code>KeyConditionExpression</code>.

</p <note>

A <code>Query</code> operation can return an empty result set and a <code>LastEvaluatedKey</code> if all the items read for the page of results are filtered out.

</p </note>

You can query a table, a local secondary index, or a global secondary index. For a query on a table or on a local secondary index, you can set the <code>ConsistentRead</code> parameter to <code>true</code> and obtain a strongly consistent result. Global secondary indexes support eventually consistent reads only, so do not specify <code>ConsistentRead</code> when querying a global secondary

[slot] RestoreTableFromBackupResponse *DynamoDBClient::restoreTableFromBackup(const RestoreTableFromBackupRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an RestoreTableFromBackupResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Creates a new table from an existing backup. Any number of users can execute up to 4 concurrent restores (any type of restore) in a given account.

</p

You can call <code>RestoreTableFromBackup</code> at a maximum rate of 10 times per

second>

You must manually set up the following on the restored

table> <ul> <li>

Auto scaling

policie> </li> <li>

IAM

policie> </li> <li>

Cloudwatch metrics and

alarm> </li> <li>

Tag> </li> <li>

Stream

setting> </li> <li>

Time to Live (TTL)

[slot] RestoreTableToPointInTimeResponse *DynamoDBClient::restoreTableToPointInTime(const RestoreTableToPointInTimeRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an RestoreTableToPointInTimeResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Restores the specified table to the specified point in time within <code>EarliestRestorableDateTime</code> and <code>LatestRestorableDateTime</code>. You can restore your table to any point in time during the last 35 days. Any number of users can execute up to 4 concurrent restores (any type of restore) in a given account.

</p

When you restore using point in time recovery, DynamoDB restores your table data to the state based on the selected date and time (day:hour:minute:second) to a new table.

</p

Along with data, the following are also included on the new restored table using point in time recovery:

</p <ul> <li>

Global secondary indexes

(GSIs> </li> <li>

Local secondary indexes

(LSIs> </li> <li>

Provisioned read and write

capacit> </li> <li>

Encryption

setting> <b>

All these settings come from the current settings of the source table at the time of restore.

</p </b> </li> </ul>

You must manually set up the following on the restored

table> <ul> <li>

Auto scaling

policie> </li> <li>

IAM

policie> </li> <li>

Cloudwatch metrics and

alarm> </li> <li>

Tag> </li> <li>

Stream

setting> </li> <li>

Time to Live (TTL)

setting> </li> <li>

Point in time recovery

[slot] ScanResponse *DynamoDBClient::scan(const ScanRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an ScanResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

The <code>Scan</code> operation returns one or more items and item attributes by accessing every item in a table or a secondary index. To have DynamoDB return fewer items, you can provide a <code>FilterExpression</code>

operation>

If the total number of scanned items exceeds the maximum data set size limit of 1 MB, the scan stops and results are returned to the user as a <code>LastEvaluatedKey</code> value to continue the scan in a subsequent operation. The results also include the number of items exceeding the limit. A scan can result in no table data meeting the filter criteria.

</p

A single <code>Scan</code> operation will read up to the maximum number of items set (if using the <code>Limit</code> parameter) or a maximum of 1 MB of data and then apply any filtering to the results using <code>FilterExpression</code>. If <code>LastEvaluatedKey</code> is present in the response, you will need to paginate the result set. For more information, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Scan.html#Scan.Pagination">Paginating the Results</a> in the <i>Amazon DynamoDB Developer Guide</i>.

</p

<code>Scan</code> operations proceed sequentially; however, for faster performance on a large table or secondary index, applications can request a parallel <code>Scan</code> operation by providing the <code>Segment</code> and <code>TotalSegments</code> parameters. For more information, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Scan.html#Scan.ParallelScan">Parallel Scan</a> in the <i>Amazon DynamoDB Developer

Guide</i>>

<code>Scan</code> uses eventually consistent reads when accessing the data in a table; therefore, the result set might not include the changes to data in the table immediately before the operation began. If you need a consistent copy of the data, as of the time that the <code>Scan</code> begins, you can set the <code>ConsistentRead</code> parameter to

[slot] TagResourceResponse *DynamoDBClient::tagResource(const TagResourceRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an TagResourceResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Associate a set of tags with an Amazon DynamoDB resource. You can then activate these user-defined tags so that they appear on the Billing and Cost Management console for cost allocation tracking. You can call TagResource up to 5 times per second, per account.

</p

For an overview on tagging DynamoDB resources, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Tagging.html">Tagging for DynamoDB</a> in the <i>Amazon DynamoDB Developer

[slot] UntagResourceResponse *DynamoDBClient::untagResource(const UntagResourceRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an UntagResourceResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Removes the association of tags from an Amazon DynamoDB resource. You can call UntagResource up to 5 times per second, per account.

</p

For an overview on tagging DynamoDB resources, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Tagging.html">Tagging for DynamoDB</a> in the <i>Amazon DynamoDB Developer

[slot] UpdateContinuousBackupsResponse *DynamoDBClient::updateContinuousBackups(const UpdateContinuousBackupsRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an UpdateContinuousBackupsResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

<code>UpdateContinuousBackups</code> enables or disables point in time recovery for the specified table. A successful <code>UpdateContinuousBackups</code> call returns the current <code>ContinuousBackupsDescription</code>. Continuous backups are <code>ENABLED</code> on all tables at table creation. If point in time recovery is enabled, <code>PointInTimeRecoveryStatus</code> will be set to

ENABLED>

Once continuous backups and point in time recovery are enabled, you can restore to any point in time within <code>EarliestRestorableDateTime</code> and <code>LatestRestorableDateTime</code>.

</p

<code>LatestRestorableDateTime</code> is typically 5 minutes before the current time. You can restore your table to any point in time during the last 35 days..

[slot] UpdateGlobalTableResponse *DynamoDBClient::updateGlobalTable(const UpdateGlobalTableRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an UpdateGlobalTableResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Adds or removes replicas in the specified global table. The global table must already exist to be able to use this operation. Any replica to be added must be empty, must have the same name as the global table, must have the same key schema, and must have DynamoDB Streams enabled and must have same provisioned and maximum write capacity

units> <note>

Although you can use <code>UpdateGlobalTable</code> to add replicas and remove replicas in a single request, for simplicity we recommend that you issue separate requests for adding or removing

replicas> </note>

If global secondary indexes are specified, then the following conditions must also be met:

</p <ul> <li>

The global secondary indexes must have the same name.

</p </li> <li>

The global secondary indexes must have the same hash key and sort key (if present).

</p </li> <li>

The global secondary indexes must have the same provisioned and maximum write capacity units.

[slot] UpdateGlobalTableSettingsResponse *DynamoDBClient::updateGlobalTableSettings(const UpdateGlobalTableSettingsRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an UpdateGlobalTableSettingsResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Updates settings for a global

[slot] UpdateItemResponse *DynamoDBClient::updateItem(const UpdateItemRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an UpdateItemResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Edits an existing item's attributes, or adds a new item to the table if it does not already exist. You can put, delete, or add attribute values. You can also perform a conditional update on an existing item (insert a new attribute name-value pair if it doesn't exist, or replace an existing name-value pair if it has certain expected attribute

values)>

You can also return the item's attribute values in the same <code>UpdateItem</code> operation using the <code>ReturnValues</code>

[slot] UpdateTableResponse *DynamoDBClient::updateTable(const UpdateTableRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an UpdateTableResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

Modifies the provisioned throughput settings, global secondary indexes, or DynamoDB Streams settings for a given

table>

You can only perform one of the following operations at

once> <ul> <li>

Modify the provisioned throughput settings of the

table> </li> <li>

Enable or disable Streams on the

table> </li> <li>

Remove a global secondary index from the

table> </li> <li>

Create a new global secondary index on the table. Once the index begins backfilling, you can use <code>UpdateTable</code> to perform other

operations> </li> </ul>

<code>UpdateTable</code> is an asynchronous operation; while it is executing, the table status changes from <code>ACTIVE</code> to <code>UPDATING</code>. While it is <code>UPDATING</code>, you cannot issue another <code>UpdateTable</code> request. When the table returns to the <code>ACTIVE</code> state, the <code>UpdateTable</code> operation is

[slot] UpdateTimeToLiveResponse *DynamoDBClient::updateTimeToLive(const UpdateTimeToLiveRequest &request)

Sends request to the DynamoDBClient service, and returns a pointer to an UpdateTimeToLiveResponse object to track the result.

Note: The caller is to take responsbility for the resulting pointer.

The UpdateTimeToLive method will enable or disable TTL for the specified table. A successful <code>UpdateTimeToLive</code> call returns the current <code>TimeToLiveSpecification</code>; it may take up to one hour for the change to fully process. Any additional <code>UpdateTimeToLive</code> calls for the same table during this one hour duration result in a <code>ValidationException</code>.

</p

TTL compares the current time in epoch time format to the time stored in the TTL attribute of an item. If the epoch time value stored in the attribute is less than the current time, the item is marked as expired and subsequently

deleted> <note>

The epoch time format is the number of seconds elapsed since 12:00:00 AM January 1st, 1970 UTC.

</p </note>

DynamoDB deletes expired items on a best-effort basis to ensure availability of throughput for other data operations.

</p <b>

DynamoDB typically deletes expired items within two days of expiration. The exact duration within which an item gets deleted after expiration is specific to the nature of the workload. Items that have expired and not been deleted will still show up in reads, queries, and

scans> </b>

As items are deleted, they are removed from any Local Secondary Index and Global Secondary Index immediately in the same eventually consistent way as a standard delete

operation>

For more information, see <a href="http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/TTL.html">Time To Live</a> in the Amazon DynamoDB Developer Guide.