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.
TableName: [required] 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.
Key: [required] 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.
Expected: This is a legacy parameter. Use ConditionExpression instead. For more information, see Expected
in the Amazon DynamoDB Developer Guide.
ConditionalOperator: This is a legacy parameter. Use ConditionExpression instead. For more information, see ConditionalOperator
in the Amazon DynamoDB Developer Guide.
ReturnValues: Use ReturnValues if you want to get the item attributes as they appeared before they were deleted. For delete_item, 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.
The ReturnValues parameter is used by several DynamoDB operations; however, delete_item does not recognize any values other than NONE or ALL_OLD.
ReturnConsumedCapacity:
ReturnItemCollectionMetrics: 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.
ConditionExpression: A condition that must be satisfied in order for a conditional delete_item to succeed.
ExpressionAttributeNames: 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:
Percentile
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:
{"#P":"Percentile"}
You could then use this substitution in an expression, as in this
example:
#P = :val
Tokens that begin with the : character are expression attribute values, which are placeholders for the actual value at runtime.
ExpressionAttributeValues: 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:
ReturnValuesOnConditionCheckFailure: An optional parameter that returns the item attributes for a delete_item 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.