Amazon DynamoDB
API Reference (API Version 2012-08-10)
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PutItem

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.

Request Syntax

{
    "Expected": 
        {
            "string" :
                {
                    "Exists": "boolean",
                    "Value": {
                        "B": "blob",
                        "BS": [
                            "blob"
                        ],
                        "N": "string",
                        "NS": [
                            "string"
                        ],
                        "S": "string",
                        "SS": [
                            "string"
                        ]
                    }
                }
        },
    "Item": 
        {
            "string" :
                {
                    "B": "blob",
                    "BS": [
                        "blob"
                    ],
                    "N": "string",
                    "NS": [
                        "string"
                    ],
                    "S": "string",
                    "SS": [
                        "string"
                    ]
                }
        },
    "ReturnConsumedCapacity": "string",
    "ReturnItemCollectionMetrics": "string",
    "ReturnValues": "string",
    "TableName": "string"
}
			

Request Parameters

The request accepts the following data in JSON format.

Note

In the following list, the required parameters are described first.

Item

A map of attribute name/value pairs, one for each attribute. Only the primary key attributes are required; you can optionally provide other attribute name-value pairs for the item.

You must provide all of the attributes for the primary key. For example, with a hash type primary key, you only need to specify the hash attribute. For a hash-and-range type primary key, you must specify both the hash attribute and the range attribute.

If you specify any attributes that are part of an index key, then the data types for those attributes must match those of the schema in the table's attribute definition.

For more information about primary keys, see Primary Key in the Amazon DynamoDB Developer Guide.

Each element in the Item map is an AttributeValue object.

Type: String to AttributeValue object map

Required: Yes

TableName

The name of the table to contain the item.

Type: String

Length constraints: Minimum length of 3. Maximum length of 255.

Required: Yes

Expected

A map of attribute/condition pairs. This is the conditional block for the PutItem operation. All the conditions must be met for the operation to succeed.

Expected allows you to provide an attribute name, and whether or not DynamoDB should check to see if the attribute value already exists; or if the attribute value exists and has a particular value before changing it.

Each item in Expected represents an attribute name for DynamoDB to check, along with the following:

  • Value - A value for DynamoDB to compare with an attribute. When performing the comparison, strongly consistent reads are used.

  • Exists - Causes DynamoDB to evaluate the value before attempting a conditional operation:

    • If Exists is true, DynamoDB will check to see if that attribute value already exists in the table. If it is found, then the operation succeeds. If it is not found, the operation fails with a ConditionalCheckFailedException.

    • If Exists is false, DynamoDB assumes that the attribute value does not exist in the table. If in fact the value does not exist, then the assumption is valid and the operation succeeds. If the value is found, despite the assumption that it does not exist, the operation fails with a ConditionalCheckFailedException.

    The default setting for Exists is true. If you supply a Value all by itself, DynamoDB assumes the attribute exists: You don't have to set Exists to true, because it is implied.

    DynamoDB returns a ValidationException if:

    • Exists is true but there is no Value to check. (You expect a value to exist, but don't specify what that value is.)

    • Exists is false but you also specify a Value. (You cannot expect an attribute to have a value, while also expecting it not to exist.)

If you specify more than one condition for Exists, then all of the conditions must evaluate to true. (In other words, the conditions are ANDed together.) Otherwise, the conditional operation will fail.

Type: String to ExpectedAttributeValue object map

Required: No

ReturnConsumedCapacity

If set to TOTAL, the response includes ConsumedCapacity data for tables and indexes. If set to INDEXES, the response includes ConsumedCapacity for indexes. If set to NONE (the default), ConsumedCapacity is not included in the response.

Type: String

Valid Values: INDEXES | TOTAL | NONE

Required: No

ReturnItemCollectionMetrics

If set to SIZE, statistics about item collections, if any, that were modified during the operation are returned in the response. If set to NONE (the default), no statistics are returned.

Type: String

Valid Values: SIZE | NONE

Required: No

ReturnValues

Use ReturnValues if you want to get the item attributes as they appeared before they were updated with the PutItem request. For PutItem, the valid values are:

  • NONE - If ReturnValues is not specified, or if its value is NONE, then nothing is returned. (This is the default for ReturnValues.)

  • ALL_OLD - If PutItem overwrote an attribute name-value pair, then the content of the old item is returned.

Type: String

Valid Values: NONE | ALL_OLD | UPDATED_OLD | ALL_NEW | UPDATED_NEW

Required: No

Response Syntax

{
    "Attributes": 
        {
            "string" :
                {
                    "B": "blob",
                    "BS": [
                        "blob"
                    ],
                    "N": "string",
                    "NS": [
                        "string"
                    ],
                    "S": "string",
                    "SS": [
                        "string"
                    ]
                }
        },
    "ConsumedCapacity": {
        "CapacityUnits": "number",
        "GlobalSecondaryIndexes": 
            {
                "string" :
                    {
                        "CapacityUnits": "number"
                    }
            },
        "LocalSecondaryIndexes": 
            {
                "string" :
                    {
                        "CapacityUnits": "number"
                    }
            },
        "Table": {
            "CapacityUnits": "number"
        },
        "TableName": "string"
    },
    "ItemCollectionMetrics": {
        "ItemCollectionKey": 
            {
                "string" :
                    {
                        "B": "blob",
                        "BS": [
                            "blob"
                        ],
                        "N": "string",
                        "NS": [
                            "string"
                        ],
                        "S": "string",
                        "SS": [
                            "string"
                        ]
                    }
            },
        "SizeEstimateRangeGB": [
            "number"
        ]
    }
}
			

Response Elements

The following data is returned in JSON format by the service.

Attributes

The attribute values as they appeared before the PutItem operation, but only if ReturnValues is specified as ALL_OLD in the request. Each element consists of an attribute name and an attribute value.

Type: String to AttributeValue object map

ConsumedCapacity

Represents the capacity units consumed by an operation. The data returned includes the total provisioned throughput consumed, along with statistics for the table and any indexes involved in the operation. ConsumedCapacity is only returned if it was asked for in the request. For more information, see Provisioned Throughput in the Amazon DynamoDB Developer Guide.

Type: ConsumedCapacity object

ItemCollectionMetrics

Information about item collections, if any, that were affected by the operation. ItemCollectionMetrics is only returned if it was asked for in the request. If the table does not have any local secondary indexes, this information is not returned in the response.

Each ItemCollectionMetrics element consists of:

  • ItemCollectionKey - The hash key value of the item collection. This is the same as the hash key of the item.

  • SizeEstimateRange - An estimate of item collection size, measured in gigabytes. This is a two-element array containing a lower bound and an upper bound for the estimate. The estimate includes the size of all the items in the table, plus the size of all attributes projected into all of the local secondary indexes on that table. Use this estimate to measure whether a local secondary index is approaching its size limit.

    The estimate is subject to change over time; therefore, do not rely on the precision or accuracy of the estimate.

Type: ItemCollectionMetrics object

Errors

For information about the errors that are common to all actions, see Common Errors.

ConditionalCheckFailedException

A condition specified in the operation could not be evaluated.

HTTP Status Code: 400

InternalServerError

An error occurred on the server side.

HTTP Status Code: 500

ItemCollectionSizeLimitExceededException

An item collection is too large. This exception is only returned for tables that have one or more local secondary indexes.

HTTP Status Code: 400

ProvisionedThroughputExceededException

The request rate is too high, or the request is too large, for the available throughput to accommodate. The AWS SDKs automatically retry requests that receive this exception; therefore, your request will eventually succeed, unless the request is too large or your retry queue is too large to finish. Reduce the frequency of requests by using the strategies listed in Error Retries and Exponential Backoff in the Amazon DynamoDB Developer Guide.

HTTP Status Code: 400

ResourceNotFoundException

The operation tried to access a nonexistent table or index. The resource may not be specified correctly, or its status may not be ACTIVE.

HTTP Status Code: 400

Examples

Put an Item

This example puts a new item into the Thread table. To prevent this new item from overwriting an existing item, "Exists" is set to false for the primary key attributes.

Sample Request

POST / HTTP/1.1
Host: dynamodb.<region>.<domain>;
X-Amz-Date: <Date>
Authorization: AWS4-HMAC-SHA256 Credential=<Credential>, SignedHeaders=content-length;content-type;host;user-agent;x-amz-content-sha256;x-amz-date;x-amz-target, Signature=<Signature>
User-Agent: <UserAgentString>
x-amz-content-sha256: <PayloadHash>
Content-Type: application/x-amz-json-1.0
Content-Length: <PayloadSizeBytes>     
Connection: Keep-Alive
X-Amz-Target: DynamoDB_20120810.PutItem 

{
    "TableName": "Thread",
    "Item": {
        "LastPostDateTime": {
            "S": "201303190422"
        },
        "Tags": {
            "SS": ["Update","Multiple Items","HelpMe"]
        },
        "ForumName": {
            "S": "Amazon DynamoDB"
        },
        "Message": {
            "S": "I want to update multiple items in a single API call. What's the best way to do that?"
        },
        "Subject": {
            "S": "How do I update multiple items?"
        },
        "LastPostedBy": {
            "S": "fred@example.com"
        }
    },
    "Expected": {
        "ForumName": {
            "Exists": false
        },
        "Subject": {
            "Exists": false
        }
    }
}
        

Sample Response

HTTP/1.1 200 OK
x-amzn-RequestId: <RequestId> 
x-amz-crc32: <Checksum>
Content-Type: application/x-amz-json-1.0
Content-Length: <PayloadSizeBytes>
Date: <Date>

{
}