Table / Action / delete_item

delete_item#

DynamoDB.Table.delete_item(**kwargs)#

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

response = table.delete_item(
    Key={
        'string': 'string'|123|Binary(b'bytes')|True|None|set(['string'])|set([123])|set([Binary(b'bytes')])|[]|{}
    },
    Expected={
        'string': {
            'Value': 'string'|123|Binary(b'bytes')|True|None|set(['string'])|set([123])|set([Binary(b'bytes')])|[]|{},
            'Exists': True|False,
            'ComparisonOperator': 'EQ'|'NE'|'IN'|'LE'|'LT'|'GE'|'GT'|'BETWEEN'|'NOT_NULL'|'NULL'|'CONTAINS'|'NOT_CONTAINS'|'BEGINS_WITH',
            'AttributeValueList': [
                'string'|123|Binary(b'bytes')|True|None|set(['string'])|set([123])|set([Binary(b'bytes')])|[]|{},
            ]
        }
    },
    ConditionalOperator='AND'|'OR',
    ReturnValues='NONE'|'ALL_OLD'|'UPDATED_OLD'|'ALL_NEW'|'UPDATED_NEW',
    ReturnConsumedCapacity='INDEXES'|'TOTAL'|'NONE',
    ReturnItemCollectionMetrics='SIZE'|'NONE',
    ConditionExpression=Attr('myattribute').eq('myvalue'),
    ExpressionAttributeNames={
        'string': 'string'
    },
    ExpressionAttributeValues={
        'string': 'string'|123|Binary(b'bytes')|True|None|set(['string'])|set([123])|set([Binary(b'bytes')])|[]|{}
    }
)

Parameters:

Key (dict) –
[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.
- (string) –
  - *(valid DynamoDB type) – *- The value of the attribute. The valid value types are listed in the DynamoDB Reference Guide.
Expected (dict) –
This is a legacy parameter. Use ConditionExpression instead. For more information, see Expected in the Amazon DynamoDB Developer Guide.
- (string) –
  - (dict) –
    
    Represents a condition to be compared with an attribute value. This condition can be used with DeleteItem, PutItem, or UpdateItem operations; if the comparison evaluates to true, the operation succeeds; if not, the operation fails. You can use ExpectedAttributeValue in one of two different ways:
    - 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.
    - Value *(valid DynamoDB type) – *- The value of the attribute. The valid value types are listed in the DynamoDB Reference Guide.
    - Exists (boolean) –
      
      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 ConditionCheckFailedException.
      - 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 ConditionCheckFailedException.
      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 provide a Value. (You cannot expect an attribute to have a value, while also expecting it not to exist.)
    - ComparisonOperator (string) –
      
      A comparator for evaluating attributes in the AttributeValueList. For example, equals, greater than, less than, etc.
      
      The following comparison operators are available:
      
      EQ | NE | LE | LT | GE | GT | NOT_NULL | NULL | CONTAINS | NOT_CONTAINS | BEGINS_WITH | IN | BETWEEN
      
      The following are descriptions of each comparison operator.
      - EQ : Equal. EQ is supported for all data types, including lists and maps. AttributeValueList can contain only one AttributeValue element of type String, Number, Binary, String Set, Number Set, or Binary Set. If an item contains an AttributeValue element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"} does not equal {"NS":["6", "2", "1"]}.
      - NE : Not equal. NE is supported for all data types, including lists and maps. AttributeValueList can contain only one AttributeValue of type String, Number, Binary, String Set, Number Set, or Binary Set. If an item contains an AttributeValue of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"} does not equal {"NS":["6", "2", "1"]}.
      - LE : Less than or equal. AttributeValueList can contain only one AttributeValue element of type String, Number, or Binary (not a set type). If an item contains an AttributeValue element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"} does not compare to {"NS":["6", "2", "1"]}.
      - LT : Less than. AttributeValueList can contain only one AttributeValue of type String, Number, or Binary (not a set type). If an item contains an AttributeValue element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"} does not compare to {"NS":["6", "2", "1"]}.
      - GE : Greater than or equal. AttributeValueList can contain only one AttributeValue element of type String, Number, or Binary (not a set type). If an item contains an AttributeValue element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"} does not compare to {"NS":["6", "2", "1"]}.
      - GT : Greater than. AttributeValueList can contain only one AttributeValue element of type String, Number, or Binary (not a set type). If an item contains an AttributeValue element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not equal {"N":"6"}. Also, {"N":"6"} does not compare to {"NS":["6", "2", "1"]}.
      - NOT_NULL : The attribute exists. NOT_NULL is supported for all data types, including lists and maps.
      Note
      This operator tests for the existence of an attribute, not its data type. If the data type of attribute “ a” is null, and you evaluate it using NOT_NULL, the result is a Boolean true. This result is because the attribute “ a” exists; its data type is not relevant to the NOT_NULL comparison operator.
      - NULL : The attribute does not exist. NULL is supported for all data types, including lists and maps.
      Note
      This operator tests for the nonexistence of an attribute, not its data type. If the data type of attribute “ a” is null, and you evaluate it using NULL, the result is a Boolean false. This is because the attribute “ a” exists; its data type is not relevant to the NULL comparison operator.
      - CONTAINS : Checks for a subsequence, or value in a set. AttributeValueList can contain only one AttributeValue element of type String, Number, or Binary (not a set type). If the target attribute of the comparison is of type String, then the operator checks for a substring match. If the target attribute of the comparison is of type Binary, then the operator looks for a subsequence of the target that matches the input. If the target attribute of the comparison is a set (” SS”, “ NS”, or “ BS”), then the operator evaluates to true if it finds an exact match with any member of the set. CONTAINS is supported for lists: When evaluating “ a CONTAINS b”, “ a” can be a list; however, “ b” cannot be a set, a map, or a list.
      - NOT_CONTAINS : Checks for absence of a subsequence, or absence of a value in a set. AttributeValueList can contain only one AttributeValue element of type String, Number, or Binary (not a set type). If the target attribute of the comparison is a String, then the operator checks for the absence of a substring match. If the target attribute of the comparison is Binary, then the operator checks for the absence of a subsequence of the target that matches the input. If the target attribute of the comparison is a set (” SS”, “ NS”, or “ BS”), then the operator evaluates to true if it does not find an exact match with any member of the set. NOT_CONTAINS is supported for lists: When evaluating “ a NOT CONTAINS b”, “ a” can be a list; however, “ b” cannot be a set, a map, or a list.
      - BEGINS_WITH : Checks for a prefix. AttributeValueList can contain only one AttributeValue of type String or Binary (not a Number or a set type). The target attribute of the comparison must be of type String or Binary (not a Number or a set type).
      - IN : Checks for matching elements in a list. AttributeValueList can contain one or more AttributeValue elements of type String, Number, or Binary. These attributes are compared against an existing attribute of an item. If any elements of the input are equal to the item attribute, the expression evaluates to true.
      - BETWEEN : Greater than or equal to the first value, and less than or equal to the second value. AttributeValueList must contain two AttributeValue elements of the same type, either String, Number, or Binary (not a set type). A target attribute matches if the target value is greater than, or equal to, the first element and less than, or equal to, the second element. If an item contains an AttributeValue element of a different type than the one provided in the request, the value does not match. For example, {"S":"6"} does not compare to {"N":"6"}. Also, {"N":"6"} does not compare to {"NS":["6", "2", "1"]}
    - AttributeValueList (list) –
      
      One or more values to evaluate against the supplied attribute. The number of values in the list depends on the ComparisonOperator being used.
      
      For type Number, value comparisons are numeric.
      
      String value comparisons for greater than, equals, or less than are based on ASCII character code values. For example, a is greater than A, and a is greater than B. For a list of code values, see http://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters.
      
      For Binary, DynamoDB treats each byte of the binary data as unsigned when it compares binary values.
      
      For information on specifying data types in JSON, see JSON Data Format in the Amazon DynamoDB Developer Guide.
      - *(valid DynamoDB type) – *- The value of the attribute. The valid value types are listed in the DynamoDB Reference Guide.
ConditionalOperator (string) – This is a legacy parameter. Use ConditionExpression instead. For more information, see ConditionalOperator in the Amazon DynamoDB Developer Guide.
ReturnValues (string) –
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.

Note
The ReturnValues parameter is used by several DynamoDB operations; however, DeleteItem does not recognize any values other than NONE or ALL_OLD.
ReturnConsumedCapacity (string) –
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.
ReturnItemCollectionMetrics (string) – 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 (condition from boto3.dynamodb.conditions.Attr method) – The condition(s) an attribute(s) must meet. Valid conditions are listed in the DynamoDB Reference Guide.
ExpressionAttributeNames (dict) –
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
Note
Tokens 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.
- (string) –
  - (string) –
ExpressionAttributeValues (dict) –
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.
- (string) –
  - *(valid DynamoDB type) – *- The value of the attribute. The valid value types are listed in the DynamoDB Reference Guide.

Return type:

dict

Returns:

Response Syntax

{
    'Attributes': {
        'string': 'string'|123|Binary(b'bytes')|True|None|set(['string'])|set([123])|set([Binary(b'bytes')])|[]|{}
    },
    'ConsumedCapacity': {
        'TableName': 'string',
        'CapacityUnits': 123.0,
        'ReadCapacityUnits': 123.0,
        'WriteCapacityUnits': 123.0,
        'Table': {
            'ReadCapacityUnits': 123.0,
            'WriteCapacityUnits': 123.0,
            'CapacityUnits': 123.0
        },
        'LocalSecondaryIndexes': {
            'string': {
                'ReadCapacityUnits': 123.0,
                'WriteCapacityUnits': 123.0,
                'CapacityUnits': 123.0
            }
        },
        'GlobalSecondaryIndexes': {
            'string': {
                'ReadCapacityUnits': 123.0,
                'WriteCapacityUnits': 123.0,
                'CapacityUnits': 123.0
            }
        }
    },
    'ItemCollectionMetrics': {
        'ItemCollectionKey': {
            'string': 'string'|123|Binary(b'bytes')|True|None|set(['string'])|set([123])|set([Binary(b'bytes')])|[]|{}
        },
        'SizeEstimateRangeGB': [
            123.0,
        ]
    }
}

Response Structure

(dict) –

Represents the output of a DeleteItem operation.
- Attributes (dict) –
  
  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.
  - (string) –
    - *(valid DynamoDB type) – *- The value of the attribute. The valid value types are listed in the DynamoDB Reference Guide.
- ConsumedCapacity (dict) –
  
  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 Throughput in the Amazon DynamoDB Developer Guide.
  - TableName (string) –
    
    The name of the table that was affected by the operation.
  - CapacityUnits (float) –
    
    The total number of capacity units consumed by the operation.
  - ReadCapacityUnits (float) –
    
    The total number of read capacity units consumed by the operation.
  - WriteCapacityUnits (float) –
    
    The total number of write capacity units consumed by the operation.
  - Table (dict) –
    
    The amount of throughput consumed on the table affected by the operation.
    - ReadCapacityUnits (float) –
      
      The total number of read capacity units consumed on a table or an index.
    - WriteCapacityUnits (float) –
      
      The total number of write capacity units consumed on a table or an index.
    - CapacityUnits (float) –
      
      The total number of capacity units consumed on a table or an index.
  - LocalSecondaryIndexes (dict) –
    
    The amount of throughput consumed on each local index affected by the operation.
    - (string) –
      - (dict) –
        
        Represents the amount of provisioned throughput capacity consumed on a table or an index.
        
        ReadCapacityUnits (float) –
        
        The total number of read capacity units consumed on a table or an index.
        
        WriteCapacityUnits (float) –
        
        The total number of write capacity units consumed on a table or an index.
        
        CapacityUnits (float) –
        
        The total number of capacity units consumed on a table or an index.
  - GlobalSecondaryIndexes (dict) –
    
    The amount of throughput consumed on each global index affected by the operation.
    - (string) –
      - (dict) –
        
        Represents the amount of provisioned throughput capacity consumed on a table or an index.
        
        ReadCapacityUnits (float) –
        
        The total number of read capacity units consumed on a table or an index.
        
        WriteCapacityUnits (float) –
        
        The total number of write capacity units consumed on a table or an index.
        
        CapacityUnits (float) –
        
        The total number of capacity units consumed on a table or an index.
- ItemCollectionMetrics (dict) –
  
  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.
  - ItemCollectionKey (dict) –
    
    The partition key value of the item collection. This value is the same as the partition key value of the item.
    - (string) –
      - *(valid DynamoDB type) – *- The value of the attribute. The valid value types are listed in the DynamoDB Reference Guide.
  - SizeEstimateRangeGB (list) –
    
    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.
    - (float) –