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 deleting items only if specific conditions are met. If those conditions are met, DynamoDB performs the delete. Otherwise, the item is not deleted.
Request Syntax{
"ConditionalOperator": "string",
"ConditionExpression": "string",
"Expected": {
"string" : {
"AttributeValueList": [
{
"B": blob,
"BOOL": boolean,
"BS": [ blob ],
"L": [
"AttributeValue"
],
"M": {
"string" : "AttributeValue"
},
"N": "string",
"NS": [ "string" ],
"NULL": boolean,
"S": "string",
"SS": [ "string" ]
}
],
"ComparisonOperator": "string",
"Exists": boolean,
"Value": {
"B": blob,
"BOOL": boolean,
"BS": [ blob ],
"L": [
"AttributeValue"
],
"M": {
"string" : "AttributeValue"
},
"N": "string",
"NS": [ "string" ],
"NULL": boolean,
"S": "string",
"SS": [ "string" ]
}
}
},
"ExpressionAttributeNames": {
"string" : "string"
},
"ExpressionAttributeValues": {
"string" : {
"B": blob,
"BOOL": boolean,
"BS": [ blob ],
"L": [
"AttributeValue"
],
"M": {
"string" : "AttributeValue"
},
"N": "string",
"NS": [ "string" ],
"NULL": boolean,
"S": "string",
"SS": [ "string" ]
}
},
"Key": {
"string" : {
"B": blob,
"BOOL": boolean,
"BS": [ blob ],
"L": [
"AttributeValue"
],
"M": {
"string" : "AttributeValue"
},
"N": "string",
"NS": [ "string" ],
"NULL": boolean,
"S": "string",
"SS": [ "string" ]
}
},
"ReturnConsumedCapacity": "string",
"ReturnItemCollectionMetrics": "string",
"ReturnValues": "string",
"ReturnValuesOnConditionCheckFailure": "string",
"TableName": "string"
}The request accepts the following data in JSON format.
NoteIn the following list, the required parameters are described first.
A map of attribute names to AttributeValue objects, representing the primary key of the item to delete.
For the primary key, you must provide all of the key attributes. For example, with a simple primary key, you only need to provide a value for the partition key. For a composite primary key, you must provide values for both the partition key and the sort key.
Type: String to AttributeValue object map
Key Length Constraints: Maximum length of 65535.
Required: Yes
The name of the table from which to delete the item. You can also provide the Amazon Resource Name (ARN) of the table in this parameter.
Type: String
Length Constraints: Minimum length of 1. Maximum length of 1024.
Required: Yes
This is a legacy parameter. Use ConditionExpression instead. For more information, see ConditionalOperator in the Amazon DynamoDB Developer Guide.
Type: String
Valid Values: AND | OR
Required: No
A condition that must be satisfied in order for a conditional DeleteItem to succeed.
An expression can contain any of the following:
Functions: attribute_exists | attribute_not_exists | attribute_type | contains | begins_with | size
These function names are case-sensitive.
Comparison operators: = | <> | < | > | <= | >= | BETWEEN | IN
Logical operators: AND | OR | NOT
For more information about condition expressions, see Condition Expressions in the Amazon DynamoDB Developer Guide.
Type: String
Required: No
This is a legacy parameter. Use ConditionExpression instead. For more information, see Expected in the Amazon DynamoDB Developer Guide.
Type: String to ExpectedAttributeValue object map
Key Length Constraints: Maximum length of 65535.
Required: No
One or more substitution tokens for attribute names in an expression. The following are some use cases for using ExpressionAttributeNames:
To access an attribute whose name conflicts with a DynamoDB reserved word.
To create a placeholder for repeating occurrences of an attribute name in an expression.
To prevent special characters in an attribute name from being misinterpreted in an expression.
Use the # character in an expression to dereference an attribute name. For example, consider the following attribute name:
The name of this attribute conflicts with a reserved word, so it cannot be used directly in an expression. (For the complete list of reserved words, see Reserved Words in the Amazon DynamoDB Developer Guide). To work around this, you could specify the following for ExpressionAttributeNames:
You could then use this substitution in an expression, as in this example:
NoteTokens that begin with the : character are expression attribute values, which are placeholders for the actual value at runtime.
For more information on expression attribute names, see Specifying Item Attributes in the Amazon DynamoDB Developer Guide.
Type: String to string map
Value Length Constraints: Maximum length of 65535.
Required: No
One or more values that can be substituted in an expression.
Use the : (colon) character in an expression to dereference an attribute value. For example, suppose that you wanted to check whether the value of the ProductStatus attribute was one of the following:
Available | Backordered | Discontinued
You would first need to specify ExpressionAttributeValues as follows:
{ ":avail":{"S":"Available"}, ":back":{"S":"Backordered"}, ":disc":{"S":"Discontinued"} }
You could then use these values in an expression, such as this:
ProductStatus IN (:avail, :back, :disc)
For more information on expression attribute values, see Condition Expressions in the Amazon DynamoDB Developer Guide.
Type: String to AttributeValue object map
Required: No
Determines the level of detail about either provisioned or on-demand throughput consumption that is returned in the response:
INDEXES - The response includes the aggregate ConsumedCapacity for the operation, together with ConsumedCapacity for each table and secondary index that was accessed.
Note that some operations, such as GetItem and BatchGetItem, do not access any indexes at all. In these cases, specifying INDEXES will only return ConsumedCapacity information for table(s).
TOTAL - The response includes only the aggregate ConsumedCapacity for the operation.
NONE - No ConsumedCapacity details are included in the response.
Type: String
Valid Values: INDEXES | TOTAL | NONE
Required: No
Determines whether item collection metrics are returned. If set to SIZE, the response includes 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
Use ReturnValues if you want to get the item attributes as they appeared before they were deleted. For DeleteItem, the valid values are:
NONE - If ReturnValues is not specified, or if its value is NONE, then nothing is returned. (This setting is the default for ReturnValues.)
ALL_OLD - The content of the old item is returned.
There is no additional cost associated with requesting a return value aside from the small network and processing overhead of receiving a larger response. No read capacity units are consumed.
NoteThe ReturnValues parameter is used by several DynamoDB operations; however, DeleteItem does not recognize any values other than NONE or ALL_OLD.
Type: String
Valid Values: NONE | ALL_OLD | UPDATED_OLD | ALL_NEW | UPDATED_NEW
Required: No
An optional parameter that returns the item attributes for a DeleteItem operation that failed a condition check.
There is no additional cost associated with requesting a return value aside from the small network and processing overhead of receiving a larger response. No read capacity units are consumed.
Type: String
Valid Values: ALL_OLD | NONE
Required: No
{
"Attributes": {
"string" : {
"B": blob,
"BOOL": boolean,
"BS": [ blob ],
"L": [
"AttributeValue"
],
"M": {
"string" : "AttributeValue"
},
"N": "string",
"NS": [ "string" ],
"NULL": boolean,
"S": "string",
"SS": [ "string" ]
}
},
"ConsumedCapacity": {
"CapacityUnits": number,
"GlobalSecondaryIndexes": {
"string" : {
"CapacityUnits": number,
"ReadCapacityUnits": number,
"WriteCapacityUnits": number
}
},
"LocalSecondaryIndexes": {
"string" : {
"CapacityUnits": number,
"ReadCapacityUnits": number,
"WriteCapacityUnits": number
}
},
"ReadCapacityUnits": number,
"Table": {
"CapacityUnits": number,
"ReadCapacityUnits": number,
"WriteCapacityUnits": number
},
"TableName": "string",
"WriteCapacityUnits": number
},
"ItemCollectionMetrics": {
"ItemCollectionKey": {
"string" : {
"B": blob,
"BOOL": boolean,
"BS": [ blob ],
"L": [
"AttributeValue"
],
"M": {
"string" : "AttributeValue"
},
"N": "string",
"NS": [ "string" ],
"NULL": boolean,
"S": "string",
"SS": [ "string" ]
}
},
"SizeEstimateRangeGB": [ number ]
}
}If the action is successful, the service sends back an HTTP 200 response.
The following data is returned in JSON format by the service.
A map of attribute names to AttributeValue objects, representing the item as it appeared before the DeleteItem operation. This map appears in the response only if ReturnValues was specified as ALL_OLD in the request.
Type: String to AttributeValue object map
Key Length Constraints: Maximum length of 65535.
The capacity units consumed by the DeleteItem 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 the ReturnConsumedCapacity parameter was specified. For more information, see Provisioned capacity mode in the Amazon DynamoDB Developer Guide.
Type: ConsumedCapacity object
Information about item collections, if any, that were affected by the DeleteItem operation. ItemCollectionMetrics is only returned if the ReturnItemCollectionMetrics parameter was specified. 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 partition key value of the item collection. This is the same as the partition key value of the item itself.
SizeEstimateRangeGB - An estimate of item collection size, in gigabytes. This value 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
For information about the errors that are common to all actions, see Common Errors.
A condition specified in the operation failed to be evaluated.
HTTP Status Code: 400
An error occurred on the server side.
HTTP Status Code: 500
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
The request was denied due to request throttling. For detailed information about why the request was throttled and the ARN of the impacted resource, find the ThrottlingReason field in the returned exception. The AWS SDKs for DynamoDB automatically retry requests that receive this exception. Your request is eventually successful, unless your retry queue is too large to finish. Reduce the frequency of requests and use exponential backoff. For more information, go to Error Retries and Exponential Backoff in the Amazon DynamoDB Developer Guide.
HTTP Status Code: 400
The request was rejected because one or more items in the request are being modified by a request in another Region.
HTTP Status Code: 400
Throughput exceeds the current throughput quota for your account. For detailed information about why the request was throttled and the ARN of the impacted resource, find the ThrottlingReason field in the returned exception. Contact Support to request a quota increase.
HTTP Status Code: 400
The operation tried to access a nonexistent table or index. The resource might not be specified correctly, or its status might not be ACTIVE.
HTTP Status Code: 400
The request was denied due to request throttling. For detailed information about why the request was throttled and the ARN of the impacted resource, find the ThrottlingReason field in the returned exception.
HTTP Status Code: 400
Operation was rejected because there is an ongoing transaction for the item.
HTTP Status Code: 400
The following example deletes an item from the Thread table, but only if that item does not already have an attribute named Replies. Because ReturnValues is set to ALL_OLD, the response contains the item as it appeared before the delete.
POST / HTTP/1.1
Host: dynamodb.<region>.<domain>;
Accept-Encoding: identity
Content-Length: <PayloadSizeBytes>
User-Agent: <UserAgentString>
Content-Type: application/x-amz-json-1.0
Authorization: AWS4-HMAC-SHA256 Credential=<Credential>, SignedHeaders=<Headers>, Signature=<Signature>
X-Amz-Date: <Date>
X-Amz-Target: DynamoDB_20120810.DeleteItem
{
"TableName": "Thread",
"Key": {
"ForumName": {
"S": "Amazon DynamoDB"
},
"Subject": {
"S": "How do I update multiple items?"
}
},
"ConditionExpression": "attribute_not_exists(Replies)",
"ReturnValues": "ALL_OLD"
}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>
{
"Attributes": {
"LastPostedBy": {
"S": "fred@example.com"
},
"ForumName": {
"S": "Amazon DynamoDB"
},
"LastPostDateTime": {
"S": "201303201023"
},
"Tags": {
"SS": ["Update","Multiple Items","HelpMe"]
},
"Subject": {
"S": "How do I update multiple items?"
},
"Message": {
"S": "I want to update multiple items in a single call. What's the best way to do that?"
}
}
}For more information about using this API in one of the language-specific AWS SDKs, see the following:
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