Amazonka.DynamoDB.UpdateItem

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

You can also return the item's attribute values in the same UpdateItem operation using the ReturnValues parameter.

Creating a Request

data UpdateItem

Represents the input of an UpdateItem operation.

See: newUpdateItem smart constructor.

Constructors

UpdateItem'

Fields

• attributeUpdates :: Maybe (HashMap Text AttributeValueUpdate)

  This is a legacy parameter. Use UpdateExpression instead. For more information, see AttributeUpdates in the Amazon DynamoDB Developer Guide.

• conditionExpression :: Maybe Text

  A condition that must be satisfied in order for a conditional update 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 Specifying Conditions in the Amazon DynamoDB Developer Guide.

• conditionalOperator :: Maybe ConditionalOperator

  This is a legacy parameter. Use ConditionExpression instead. For more information, see ConditionalOperator in the Amazon DynamoDB Developer Guide.

• expected :: Maybe (HashMap Text ExpectedAttributeValue)

  This is a legacy parameter. Use ConditionExpression instead. For more information, see Expected in the Amazon DynamoDB Developer Guide.

• expressionAttributeNames :: Maybe (HashMap Text Text)

  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.

  For more information about expression attribute names, see Specifying Item Attributes in the Amazon DynamoDB Developer Guide.

• expressionAttributeValues :: Maybe (HashMap Text AttributeValue)

  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.

• returnConsumedCapacity :: Maybe ReturnConsumedCapacity
• returnItemCollectionMetrics :: Maybe 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.

• returnValues :: Maybe ReturnValue

  Use ReturnValues if you want to get the item attributes as they appear before or after they are updated. For UpdateItem, 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 - Returns all of the attributes of the item, as they appeared before the UpdateItem operation.
  • UPDATED_OLD - Returns only the updated attributes, as they appeared before the UpdateItem operation.
  • ALL_NEW - Returns all of the attributes of the item, as they appear after the UpdateItem operation.
  • UPDATED_NEW - Returns only the updated attributes, as they appear after the UpdateItem operation.

  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 values returned are strongly consistent.

• updateExpression :: Maybe Text

  An expression that defines one or more attributes to be updated, the action to be performed on them, and new values for them.

  The following action values are available for UpdateExpression.

  • SET - Adds one or more attributes and values to an item. If any of these attributes already exist, they are replaced by the new values. You can also use SET to add or subtract from an attribute that is of type Number. For example: SET myNum = myNum + :val

    SET supports the following functions:

    • if_not_exists (path, operand) - if the item does not contain an attribute at the specified path, then if_not_exists evaluates to operand; otherwise, it evaluates to path. You can use this function to avoid overwriting an attribute that may already be present in the item.
    • list_append (operand, operand) - evaluates to a list with a new element added to it. You can append the new element to the start or the end of the list by reversing the order of the operands.

    These function names are case-sensitive.

  • REMOVE - Removes one or more attributes from an item.

  • ADD - Adds the specified value to the item, if the attribute does not already exist. If the attribute does exist, then the behavior of ADD depends on the data type of the attribute:

    • If the existing attribute is a number, and if Value is also a number, then Value is mathematically added to the existing attribute. If Value is a negative number, then it is subtracted from the existing attribute.

      If you use ADD to increment or decrement a number value for an item that doesn't exist before the update, DynamoDB uses 0 as the initial value.

      Similarly, if you use ADD for an existing item to increment or decrement an attribute value that doesn't exist before the update, DynamoDB uses 0 as the initial value. For example, suppose that the item you want to update doesn't have an attribute named itemcount, but you decide to ADD the number 3 to this attribute anyway. DynamoDB will create the itemcount attribute, set its initial value to 0, and finally add 3 to it. The result will be a new itemcount attribute in the item, with a value of 3.

    • If the existing data type is a set and if Value is also a set, then Value is added to the existing set. For example, if the attribute value is the set [1,2], and the ADD action specified [3], then the final attribute value is [1,2,3]. An error occurs if an ADD action is specified for a set attribute and the attribute type specified does not match the existing set type.

      Both sets must have the same primitive data type. For example, if the existing data type is a set of strings, the Value must also be a set of strings.

    The ADD action only supports Number and set data types. In addition, ADD can only be used on top-level attributes, not nested attributes.

  • DELETE - Deletes an element from a set.

    If a set of values is specified, then those values are subtracted from the old set. For example, if the attribute value was the set [a,b,c] and the DELETE action specifies [a,c], then the final attribute value is [b]. Specifying an empty set is an error.

    The DELETE action only supports set data types. In addition, DELETE can only be used on top-level attributes, not nested attributes.

  You can have many actions in a single expression, such as the following: SET a=:value1, b=:value2 DELETE :value3, :value4, :value5

  For more information on update expressions, see Modifying Items and Attributes in the Amazon DynamoDB Developer Guide.

• tableName :: Text

  The name of the table containing the item to update.

• key :: HashMap Text AttributeValue

  The primary key of the item to be updated. Each element consists of an attribute name and a value for that attribute.

  For the primary key, you must provide all of the 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.

Instances

ToJSON UpdateItem

Defined in Amazonka.DynamoDB.UpdateItem

Methods

toJSON :: UpdateItem -> Value

toEncoding :: UpdateItem -> Encoding

toJSONList :: [UpdateItem] -> Value

toEncodingList :: [UpdateItem] -> Encoding

ToHeaders UpdateItem

Defined in Amazonka.DynamoDB.UpdateItem

Methods

toHeaders :: UpdateItem -> [Header]

ToPath UpdateItem

Defined in Amazonka.DynamoDB.UpdateItem

Methods

toPath :: UpdateItem -> ByteString

ToQuery UpdateItem

Defined in Amazonka.DynamoDB.UpdateItem

Methods

toQuery :: UpdateItem -> QueryString

AWSRequest UpdateItem

Defined in Amazonka.DynamoDB.UpdateItem

Associated Types

type AWSResponse UpdateItem

Methods

request :: (Service -> Service) -> UpdateItem -> Request UpdateItem

response :: MonadResource m => (ByteStringLazy -> IO ByteStringLazy) -> Service -> Proxy UpdateItem -> ClientResponse ClientBody -> m (Either Error (ClientResponse (AWSResponse UpdateItem)))

Generic UpdateItem

Defined in Amazonka.DynamoDB.UpdateItem

Associated Types

type Rep UpdateItem :: Type -> Type

Methods

from :: UpdateItem -> Rep UpdateItem x

to :: Rep UpdateItem x -> UpdateItem

Read UpdateItem

Defined in Amazonka.DynamoDB.UpdateItem

Methods

readsPrec :: Int -> ReadS UpdateItem

readList :: ReadS [UpdateItem]

readPrec :: ReadPrec UpdateItem

readListPrec :: ReadPrec [UpdateItem]

Show UpdateItem

Defined in Amazonka.DynamoDB.UpdateItem

Methods

showsPrec :: Int -> UpdateItem -> ShowS

show :: UpdateItem -> String

showList :: [UpdateItem] -> ShowS

NFData UpdateItem

Defined in Amazonka.DynamoDB.UpdateItem

Methods

rnf :: UpdateItem -> ()

Eq UpdateItem

Defined in Amazonka.DynamoDB.UpdateItem

Methods

(==) :: UpdateItem -> UpdateItem -> Bool

(/=) :: UpdateItem -> UpdateItem -> Bool

Hashable UpdateItem

Defined in Amazonka.DynamoDB.UpdateItem

Methods

hashWithSalt :: Int -> UpdateItem -> Int

hash :: UpdateItem -> Int

type AWSResponse UpdateItem

Defined in Amazonka.DynamoDB.UpdateItem

type AWSResponse UpdateItem = UpdateItemResponse

type Rep UpdateItem

Defined in Amazonka.DynamoDB.UpdateItem

type Rep UpdateItem = D1 ('MetaData "UpdateItem" "Amazonka.DynamoDB.UpdateItem" "amazonka-dynamodb-2.0-GNxlseyeFiu302JKQwQrUS" 'False) (C1 ('MetaCons "UpdateItem'" 'PrefixI 'True) (((S1 ('MetaSel ('Just "attributeUpdates") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe (HashMap Text AttributeValueUpdate))) :*: (S1 ('MetaSel ('Just "conditionExpression") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe Text)) :*: S1 ('MetaSel ('Just "conditionalOperator") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe ConditionalOperator)))) :*: (S1 ('MetaSel ('Just "expected") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe (HashMap Text ExpectedAttributeValue))) :*: (S1 ('MetaSel ('Just "expressionAttributeNames") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe (HashMap Text Text))) :*: S1 ('MetaSel ('Just "expressionAttributeValues") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe (HashMap Text AttributeValue)))))) :*: ((S1 ('MetaSel ('Just "returnConsumedCapacity") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe ReturnConsumedCapacity)) :*: (S1 ('MetaSel ('Just "returnItemCollectionMetrics") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe ReturnItemCollectionMetrics)) :*: S1 ('MetaSel ('Just "returnValues") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe ReturnValue)))) :*: (S1 ('MetaSel ('Just "updateExpression") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe Text)) :*: (S1 ('MetaSel ('Just "tableName") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 Text) :*: S1 ('MetaSel ('Just "key") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (HashMap Text AttributeValue)))))))

newUpdateItem

Arguments

:: Text

UpdateItem

-> UpdateItem

Create a value of UpdateItem with all optional fields omitted.

Use generic-lens or optics to modify other optional fields.

The following record fields are available, with the corresponding lenses provided for backwards compatibility:

$sel:attributeUpdates:UpdateItem', updateItem_attributeUpdates - This is a legacy parameter. Use UpdateExpression instead. For more information, see AttributeUpdates in the Amazon DynamoDB Developer Guide.

UpdateItem, updateItem_conditionExpression - A condition that must be satisfied in order for a conditional update 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 Specifying Conditions in the Amazon DynamoDB Developer Guide.

$sel:conditionalOperator:UpdateItem', updateItem_conditionalOperator - This is a legacy parameter. Use ConditionExpression instead. For more information, see ConditionalOperator in the Amazon DynamoDB Developer Guide.

$sel:expected:UpdateItem', updateItem_expected - This is a legacy parameter. Use ConditionExpression instead. For more information, see Expected in the Amazon DynamoDB Developer Guide.

UpdateItem, updateItem_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.

For more information about expression attribute names, see Specifying Item Attributes in the Amazon DynamoDB Developer Guide.

UpdateItem, updateItem_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:

{ ":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.

$sel:returnConsumedCapacity:UpdateItem', updateItem_returnConsumedCapacity - Undocumented member.

$sel:returnItemCollectionMetrics:UpdateItem', updateItem_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.

$sel:returnValues:UpdateItem', updateItem_returnValues - Use ReturnValues if you want to get the item attributes as they appear before or after they are updated. For UpdateItem, 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 - Returns all of the attributes of the item, as they appeared before the UpdateItem operation.
• UPDATED_OLD - Returns only the updated attributes, as they appeared before the UpdateItem operation.
• ALL_NEW - Returns all of the attributes of the item, as they appear after the UpdateItem operation.
• UPDATED_NEW - Returns only the updated attributes, as they appear after the UpdateItem operation.

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 values returned are strongly consistent.

UpdateItem, updateItem_updateExpression - An expression that defines one or more attributes to be updated, the action to be performed on them, and new values for them.

The following action values are available for UpdateExpression.

• SET - Adds one or more attributes and values to an item. If any of these attributes already exist, they are replaced by the new values. You can also use SET to add or subtract from an attribute that is of type Number. For example: SET myNum = myNum + :val

  SET supports the following functions:

  • if_not_exists (path, operand) - if the item does not contain an attribute at the specified path, then if_not_exists evaluates to operand; otherwise, it evaluates to path. You can use this function to avoid overwriting an attribute that may already be present in the item.
  • list_append (operand, operand) - evaluates to a list with a new element added to it. You can append the new element to the start or the end of the list by reversing the order of the operands.

  These function names are case-sensitive.

• REMOVE - Removes one or more attributes from an item.

• ADD - Adds the specified value to the item, if the attribute does not already exist. If the attribute does exist, then the behavior of ADD depends on the data type of the attribute:

  • If the existing attribute is a number, and if Value is also a number, then Value is mathematically added to the existing attribute. If Value is a negative number, then it is subtracted from the existing attribute.

    If you use ADD to increment or decrement a number value for an item that doesn't exist before the update, DynamoDB uses 0 as the initial value.

    Similarly, if you use ADD for an existing item to increment or decrement an attribute value that doesn't exist before the update, DynamoDB uses 0 as the initial value. For example, suppose that the item you want to update doesn't have an attribute named itemcount, but you decide to ADD the number 3 to this attribute anyway. DynamoDB will create the itemcount attribute, set its initial value to 0, and finally add 3 to it. The result will be a new itemcount attribute in the item, with a value of 3.

  • If the existing data type is a set and if Value is also a set, then Value is added to the existing set. For example, if the attribute value is the set [1,2], and the ADD action specified [3], then the final attribute value is [1,2,3]. An error occurs if an ADD action is specified for a set attribute and the attribute type specified does not match the existing set type.

    Both sets must have the same primitive data type. For example, if the existing data type is a set of strings, the Value must also be a set of strings.

  The ADD action only supports Number and set data types. In addition, ADD can only be used on top-level attributes, not nested attributes.

• DELETE - Deletes an element from a set.

  If a set of values is specified, then those values are subtracted from the old set. For example, if the attribute value was the set [a,b,c] and the DELETE action specifies [a,c], then the final attribute value is [b]. Specifying an empty set is an error.

  The DELETE action only supports set data types. In addition, DELETE can only be used on top-level attributes, not nested attributes.

You can have many actions in a single expression, such as the following: SET a=:value1, b=:value2 DELETE :value3, :value4, :value5

For more information on update expressions, see Modifying Items and Attributes in the Amazon DynamoDB Developer Guide.

UpdateItem, updateItem_tableName - The name of the table containing the item to update.

UpdateItem, updateItem_key - The primary key of the item to be updated. Each element consists of an attribute name and a value for that attribute.

For the primary key, you must provide all of the 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.

Request Lenses

updateItem_attributeUpdates :: Lens' UpdateItem (Maybe (HashMap Text AttributeValueUpdate))

This is a legacy parameter. Use UpdateExpression instead. For more information, see AttributeUpdates in the Amazon DynamoDB Developer Guide.

updateItem_conditionExpression :: Lens' UpdateItem (Maybe Text)

A condition that must be satisfied in order for a conditional update 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 Specifying Conditions in the Amazon DynamoDB Developer Guide.

updateItem_conditionalOperator :: Lens' UpdateItem (Maybe ConditionalOperator)

This is a legacy parameter. Use ConditionExpression instead. For more information, see ConditionalOperator in the Amazon DynamoDB Developer Guide.

updateItem_expected :: Lens' UpdateItem (Maybe (HashMap Text ExpectedAttributeValue))

This is a legacy parameter. Use ConditionExpression instead. For more information, see Expected in the Amazon DynamoDB Developer Guide.

updateItem_expressionAttributeNames :: Lens' UpdateItem (Maybe (HashMap Text Text))

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.

For more information about expression attribute names, see Specifying Item Attributes in the Amazon DynamoDB Developer Guide.

updateItem_expressionAttributeValues :: Lens' UpdateItem (Maybe (HashMap Text AttributeValue))

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.

updateItem_returnConsumedCapacity :: Lens' UpdateItem (Maybe ReturnConsumedCapacity)

Undocumented member.

updateItem_returnItemCollectionMetrics :: Lens' UpdateItem (Maybe 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.

updateItem_returnValues :: Lens' UpdateItem (Maybe ReturnValue)

Use ReturnValues if you want to get the item attributes as they appear before or after they are updated. For UpdateItem, 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 - Returns all of the attributes of the item, as they appeared before the UpdateItem operation.
• UPDATED_OLD - Returns only the updated attributes, as they appeared before the UpdateItem operation.
• ALL_NEW - Returns all of the attributes of the item, as they appear after the UpdateItem operation.
• UPDATED_NEW - Returns only the updated attributes, as they appear after the UpdateItem operation.

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 values returned are strongly consistent.

updateItem_updateExpression :: Lens' UpdateItem (Maybe Text)

An expression that defines one or more attributes to be updated, the action to be performed on them, and new values for them.

The following action values are available for UpdateExpression.

• SET - Adds one or more attributes and values to an item. If any of these attributes already exist, they are replaced by the new values. You can also use SET to add or subtract from an attribute that is of type Number. For example: SET myNum = myNum + :val

  SET supports the following functions:

  • if_not_exists (path, operand) - if the item does not contain an attribute at the specified path, then if_not_exists evaluates to operand; otherwise, it evaluates to path. You can use this function to avoid overwriting an attribute that may already be present in the item.
  • list_append (operand, operand) - evaluates to a list with a new element added to it. You can append the new element to the start or the end of the list by reversing the order of the operands.

  These function names are case-sensitive.

• REMOVE - Removes one or more attributes from an item.

• ADD - Adds the specified value to the item, if the attribute does not already exist. If the attribute does exist, then the behavior of ADD depends on the data type of the attribute:

  • If the existing attribute is a number, and if Value is also a number, then Value is mathematically added to the existing attribute. If Value is a negative number, then it is subtracted from the existing attribute.

    If you use ADD to increment or decrement a number value for an item that doesn't exist before the update, DynamoDB uses 0 as the initial value.

    Similarly, if you use ADD for an existing item to increment or decrement an attribute value that doesn't exist before the update, DynamoDB uses 0 as the initial value. For example, suppose that the item you want to update doesn't have an attribute named itemcount, but you decide to ADD the number 3 to this attribute anyway. DynamoDB will create the itemcount attribute, set its initial value to 0, and finally add 3 to it. The result will be a new itemcount attribute in the item, with a value of 3.

  • If the existing data type is a set and if Value is also a set, then Value is added to the existing set. For example, if the attribute value is the set [1,2], and the ADD action specified [3], then the final attribute value is [1,2,3]. An error occurs if an ADD action is specified for a set attribute and the attribute type specified does not match the existing set type.

    Both sets must have the same primitive data type. For example, if the existing data type is a set of strings, the Value must also be a set of strings.

  The ADD action only supports Number and set data types. In addition, ADD can only be used on top-level attributes, not nested attributes.

• DELETE - Deletes an element from a set.

  If a set of values is specified, then those values are subtracted from the old set. For example, if the attribute value was the set [a,b,c] and the DELETE action specifies [a,c], then the final attribute value is [b]. Specifying an empty set is an error.

  The DELETE action only supports set data types. In addition, DELETE can only be used on top-level attributes, not nested attributes.

You can have many actions in a single expression, such as the following: SET a=:value1, b=:value2 DELETE :value3, :value4, :value5

For more information on update expressions, see Modifying Items and Attributes in the Amazon DynamoDB Developer Guide.

updateItem_tableName :: Lens' UpdateItem Text

The name of the table containing the item to update.

updateItem_key :: Lens' UpdateItem (HashMap Text AttributeValue)

The primary key of the item to be updated. Each element consists of an attribute name and a value for that attribute.

For the primary key, you must provide all of the 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.

Destructuring the Response

data UpdateItemResponse

Represents the output of an UpdateItem operation.

See: newUpdateItemResponse smart constructor.

Constructors

UpdateItemResponse'

Fields

• attributes :: Maybe (HashMap Text AttributeValue)

  A map of attribute values as they appear before or after the UpdateItem operation, as determined by the ReturnValues parameter.

  The Attributes map is only present if ReturnValues was specified as something other than NONE in the request. Each element represents one attribute.

• consumedCapacity :: Maybe ConsumedCapacity

  The capacity units consumed by the UpdateItem 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.

• itemCollectionMetrics :: Maybe ItemCollectionMetrics

  Information about item collections, if any, that were affected by the UpdateItem 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.

• httpStatus :: Int

  The response's http status code.

Instances

Generic UpdateItemResponse

Defined in Amazonka.DynamoDB.UpdateItem

Associated Types

type Rep UpdateItemResponse :: Type -> Type

Methods

from :: UpdateItemResponse -> Rep UpdateItemResponse x

to :: Rep UpdateItemResponse x -> UpdateItemResponse

Read UpdateItemResponse

Defined in Amazonka.DynamoDB.UpdateItem

Methods

readsPrec :: Int -> ReadS UpdateItemResponse

readList :: ReadS [UpdateItemResponse]

readPrec :: ReadPrec UpdateItemResponse

readListPrec :: ReadPrec [UpdateItemResponse]

Show UpdateItemResponse

Defined in Amazonka.DynamoDB.UpdateItem

Methods

showsPrec :: Int -> UpdateItemResponse -> ShowS

show :: UpdateItemResponse -> String

showList :: [UpdateItemResponse] -> ShowS

NFData UpdateItemResponse

Defined in Amazonka.DynamoDB.UpdateItem

Methods

rnf :: UpdateItemResponse -> ()

Eq UpdateItemResponse

Defined in Amazonka.DynamoDB.UpdateItem

Methods

(==) :: UpdateItemResponse -> UpdateItemResponse -> Bool

(/=) :: UpdateItemResponse -> UpdateItemResponse -> Bool

type Rep UpdateItemResponse

Defined in Amazonka.DynamoDB.UpdateItem

type Rep UpdateItemResponse = D1 ('MetaData "UpdateItemResponse" "Amazonka.DynamoDB.UpdateItem" "amazonka-dynamodb-2.0-GNxlseyeFiu302JKQwQrUS" 'False) (C1 ('MetaCons "UpdateItemResponse'" 'PrefixI 'True) ((S1 ('MetaSel ('Just "attributes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe (HashMap Text AttributeValue))) :*: S1 ('MetaSel ('Just "consumedCapacity") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe ConsumedCapacity))) :*: (S1 ('MetaSel ('Just "itemCollectionMetrics") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 (Maybe ItemCollectionMetrics)) :*: S1 ('MetaSel ('Just "httpStatus") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedStrict) (Rec0 Int))))

newUpdateItemResponse

Arguments

:: Int

$sel:httpStatus:UpdateItemResponse'

-> UpdateItemResponse

Create a value of UpdateItemResponse with all optional fields omitted.

Use generic-lens or optics to modify other optional fields.

The following record fields are available, with the corresponding lenses provided for backwards compatibility:

$sel:attributes:UpdateItemResponse', updateItemResponse_attributes - A map of attribute values as they appear before or after the UpdateItem operation, as determined by the ReturnValues parameter.

The Attributes map is only present if ReturnValues was specified as something other than NONE in the request. Each element represents one attribute.

$sel:consumedCapacity:UpdateItemResponse', updateItemResponse_consumedCapacity - The capacity units consumed by the UpdateItem 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.

$sel:itemCollectionMetrics:UpdateItemResponse', updateItemResponse_itemCollectionMetrics - Information about item collections, if any, that were affected by the UpdateItem 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.

$sel:httpStatus:UpdateItemResponse', updateItemResponse_httpStatus - The response's http status code.

Response Lenses

updateItemResponse_attributes :: Lens' UpdateItemResponse (Maybe (HashMap Text AttributeValue))

A map of attribute values as they appear before or after the UpdateItem operation, as determined by the ReturnValues parameter.

The Attributes map is only present if ReturnValues was specified as something other than NONE in the request. Each element represents one attribute.

updateItemResponse_consumedCapacity :: Lens' UpdateItemResponse (Maybe ConsumedCapacity)

The capacity units consumed by the UpdateItem 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.

updateItemResponse_itemCollectionMetrics :: Lens' UpdateItemResponse (Maybe ItemCollectionMetrics)

Information about item collections, if any, that were affected by the UpdateItem 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.

updateItemResponse_httpStatus :: Lens' UpdateItemResponse Int

The response's http status code.