C# (CSharp) Amazon.DynamoDBv2.Model Namespace

Represents the data for an attribute. You can set one, and only one, of the elements.

Attribute values cannot be null; string and binary type attributes must have lengths greater than zero; and set type attributes must not be empty. Requests with empty values will be rejected with a ValidationException exception.

The BatchGetItem 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 1 MB of data, which can comprise as many as 100 items. BatchGetItem 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 UnprocessedKeys . You can use this value to retry the operation starting with the next item to get.

For example, if you ask to retrieve 100 items, but each individual item is 50 KB in size, the system returns 20 items (1 MB) and an appropriate UnprocessedKeys 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 dataset.

If no items can be processed because of insufficient provisioned throughput on each of the tables involved in the request, BatchGetItem throws ProvisionedThroughputExceededException .

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

In order to minimize response latency, BatchGetItem fetches items in parallel.

When designing your application, keep in mind that Amazon DynamoDB does not return attributes in any particular order. To help parse the response by item, include the primary key values for the items in your request in the AttributesToGet 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 Capacity Units Calculations in the Amazon DynamoDB Developer Guide.

The individual PutItem and DeleteItem operations specified in BatchWriteItem are atomic; however BatchWriteItem 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 UnprocessedItems response parameter. You can investigate and optionally resend the requests. Typically, you would call BatchWriteItem in a loop. Each iteration would check for unprocessed items and submit a new BatchWriteItem request with those unprocessed items until all items have been processed.

Note that if none of the items can be processed due to insufficient provisioned throughput on all of the tables in the request, then BatchWriteItem will return a ProvisionedThroughputExceededException.

With BatchWriteItem, 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, BatchWriteItem does not behave in the same way as individual PutItem and DeleteItem calls would. For example, you cannot specify conditions on individual put and delete requests, and BatchWriteItem 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, BatchWriteItem provides an alternative where the API 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:

• One or more tables specified in the BatchWriteItem request does not exist.

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

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

• There are more than 25 requests in the batch.

• Any individual item in a batch exceeds 400 KB.

• The total request size exceeds 16 MB.

Represents the output of a BatchWriteItem operation.

• For a Query operation, Condition is used for specifying the KeyConditions to use when querying a table or an index. For KeyConditions, only the following comparison operators are supported:

  EQ | LE | LT | GE | GT | BEGINS_WITH | BETWEEN

  Condition is also used in a QueryFilter, which evaluates the query results and returns only the desired values.

• For a Scan operation, Condition is used in a ScanFilter, which evaluates the scan results and returns only the desired values.

The table name that consumed provisioned throughput, and the number of capacity units consumed by it. ConsumedCapacity is only returned if it was asked for in the request. For more information, see Provisioned Throughput in the Amazon DynamoDB Developer Guide.

The CreateTable 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.

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

If you want to create multiple tables with local secondary indexes on them, you must create them sequentially. Only one table with local secondary indexes can be in the CREATING state at any given time.

You can use the DescribeTable API to check the table status.

Represents the output of a CreateTable operation.

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 ReturnValues parameter.

Unless you specify conditions, the DeleteItem is an idempotent operation; running it multiple times on the same item or attribute does not result in an error response.

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

Represents the output of a DeleteItem operation.

Represents a request to perform a DeleteItem operation on an item.

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

NOTE: Amazon DynamoDB might continue to accept data read and write operations, such as GetItem and PutItem, on a table in the DELETING state until the table deletion is complete.

When you delete a table, any local secondary indexes on that table are also deleted.

Use the DescribeTable API to check the status of the table.

Represents the output of a DeleteTable operation.

Each shard in the stream has a SequenceNumberRange associated with it. If the SequenceNumberRange has a StartingSequenceNumber but no EndingSequenceNumber, then the shard is still open (able to receive more stream records). If both StartingSequenceNumber and EndingSequenceNumber are present, then that shard is closed and can no longer receive more data.

Represents the output of a DescribeTable operation.

• Use AttributeValueList to specify one or more values to compare against an attribute. Use ComparisonOperator to specify how you want to perform the comparison. If the comparison evaluates to true, then the conditional operation succeeds.

• Use Value to specify a value that DynamoDB will compare against an attribute. If the values match, then ExpectedAttributeValue evaluates to true and the conditional operation succeeds. Optionally, you can also set Exists to false, indicating that you do not expect to find the attribute value in the table. In this case, the conditional operation succeeds only if the comparison evaluates to false.

Value and Exists are incompatible with AttributeValueList and ComparisonOperator. Note that if you use both sets of parameters at once, DynamoDB will return a ValidationException exception.

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

Represents the output of a GetItem operation.

Specify a shard iterator using the ShardIterator parameter. The shard iterator specifies the position in the shard from which you want to start reading stream records sequentially. If there are no stream records available in the portion of the shard that the iterator points to, GetRecords returns an empty list. Note that it might take multiple calls to get to a portion of the shard that contains stream records.

A KeySchemaElement represents exactly one attribute of the primary key. For example, a simple primary key would be represented by one KeySchemaElement (for the partition key). A composite primary key would require one KeySchemaElement for the partition key, and another KeySchemaElement for the sort key.

A KeySchemaElement must be a scalar, top-level attribute (not a nested attribute). The data type must be one of String, Number, or Binary. The attribute cannot be nested within a List or a Map.

Represents a set of primary keys and, for each key, the attributes to retrieve from the table.

Returns an array of all the tables associated with the current account and endpoint.

Represents the output of a ListTables operation.

Represents the properties of a secondary index.

The provisioned throughput settings for the specified table. The settings can be modified using the UpdateTable operation.

For current minimum and maximum provisioned throughput values, see Limits in the Amazon DynamoDB Developer Guide.

Describes the provisioned throughput settings for the table, consisting of read and write capacity units, along with data about increases and decreases.

Creates a new item, or replaces an old item with a new item. If an item already exists in the specified table with the same primary key, the new item completely replaces the existing item. You can perform a conditional put (insert a new item if one with the specified primary key doesn't exist), or replace an existing item if it has certain attribute values.

In addition to putting an item, you can also return the item's attribute values in the same operation, using the ReturnValues parameter.

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 ValidationException .

You can request that PutItem return either a copy of the old item (before the update) or a copy of the new item (after the update). For more information, see the ReturnValues description.

NOTE: To prevent a new item from replacing an existing item, use a conditional put operation with Exists set to false for the primary key attribute, or attributes.

For more information about using this API, see Working with Items in the Amazon DynamoDB Developer Guide.

Represents a request to perform a PutItem operation on an item.

A Query operation directly accesses items from a table using the table primary key, or from an index using the index key. You must provide a specific hash key value. You can narrow the scope of the query by using comparison operators on the range key value, or on the index key. You can use the ScanIndexForward parameter to get results in forward or reverse order, by range key or by index key.

Queries that do not return results consume the minimum read capacity units according to the type of read.

If the total number of items meeting the query criteria exceeds the result set size limit of 1 MB, the query stops and results are returned to the user with a LastEvaluatedKey to continue the query in a subsequent operation. Unlike a Scan operation, a Query operation never returns an empty result set and a LastEvaluatedKey . The LastEvaluatedKey is only provided if the results exceed 1 MB, or if you have used Limit .

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 ConsistentRead to true and obtain a strongly consistent result. Global secondary indexes support eventually consistent reads only, so do not specify ConsistentRead when querying a global secondary index.

Represents the output of a Query operation.

The Scan operation returns one or more items and item attributes by accessing every item in the table. To have Amazon DynamoDB return fewer items, you can provide a ScanFilter .

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 with a LastEvaluatedKey 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.

The result set is eventually consistent.

Represents the output of a Scan operation.

Contains the properties of a table.

Edits an existing item's attributes, or inserts a new item if it does not already exist. You can put, delete, or add attribute values. You can also perform a conditional update (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).

In addition to updating an item, you can also return the item's attribute values in the same operation, using the ReturnValues parameter.

Represents the output of an UpdateItem operation.

Updates the provisioned throughput for the given table. Setting the throughput for a table helps you manage performance and is part of the provisioned throughput feature of Amazon DynamoDB.

The provisioned throughput values can be upgraded or downgraded based on the maximums and minimums listed in the Limits section in the Amazon DynamoDB Developer Guide.

The table must be in the ACTIVE state for this operation to succeed. UpdateTable is an asynchronous operation; while executing the operation, the table is in the UPDATING state. While the table is in the UPDATING state, the table still has the provisioned throughput from before the call. The new provisioned throughput setting is in effect only when the table returns to the ACTIVE state after the UpdateTable operation.

You cannot add, modify or delete local secondary indexes using UpdateTable . Local secondary indexes can only be defined at table creation time.

Represents the output of an UpdateTable operation.

Represents an operation to perform - either DeleteItem or PutItem . You can only specify one of these operations, not both, in a single WriteRequest . If you do need to perform both of these operations, you will need to specify two separate WriteRequest objects.