{-# LANGUAGE DataKinds #-} {-# LANGUAGE DeriveGeneric #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE GeneralizedNewtypeDeriving #-} {-# LANGUAGE LambdaCase #-} {-# LANGUAGE NoImplicitPrelude #-} {-# LANGUAGE OverloadedStrings #-} {-# LANGUAGE RecordWildCards #-} {-# LANGUAGE TypeFamilies #-} {-# OPTIONS_GHC -fno-warn-unused-imports #-} -- Module : Network.AWS.DynamoDB.UpdateItem -- Copyright : (c) 2013-2014 Brendan Hay <brendan.g.hay@gmail.com> -- License : This Source Code Form is subject to the terms of -- the Mozilla Public License, v. 2.0. -- A copy of the MPL can be found in the LICENSE file or -- you can obtain it at http://mozilla.org/MPL/2.0/. -- Maintainer : Brendan Hay <brendan.g.hay@gmail.com> -- Stability : experimental -- Portability : non-portable (GHC extensions) -- -- Derived from AWS service descriptions, licensed under Apache 2.0. -- | 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 (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. -- -- <http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_UpdateItem.html> module Network.AWS.DynamoDB.UpdateItem ( -- * Request UpdateItem -- ** Request constructor , updateItem -- ** Request lenses , uiAttributeUpdates , uiConditionExpression , uiConditionalOperator , uiExpected , uiExpressionAttributeNames , uiExpressionAttributeValues , uiKey , uiReturnConsumedCapacity , uiReturnItemCollectionMetrics , uiReturnValues , uiTableName , uiUpdateExpression -- * Response , UpdateItemResponse -- ** Response constructor , updateItemResponse -- ** Response lenses , uirAttributes , uirConsumedCapacity , uirItemCollectionMetrics ) where import Network.AWS.Prelude import Network.AWS.Request.JSON import Network.AWS.DynamoDB.Types import qualified GHC.Exts data UpdateItem = UpdateItem { _uiAttributeUpdates :: Map Text AttributeValueUpdate , _uiConditionExpression :: Maybe Text , _uiConditionalOperator :: Maybe ConditionalOperator , _uiExpected :: Map Text ExpectedAttributeValue , _uiExpressionAttributeNames :: Map Text Text , _uiExpressionAttributeValues :: Map Text AttributeValue , _uiKey :: Map Text AttributeValue , _uiReturnConsumedCapacity :: Maybe ReturnConsumedCapacity , _uiReturnItemCollectionMetrics :: Maybe ReturnItemCollectionMetrics , _uiReturnValues :: Maybe ReturnValue , _uiTableName :: Text , _uiUpdateExpression :: Maybe Text } deriving (Eq, Read, Show) -- | 'UpdateItem' constructor. -- -- The fields accessible through corresponding lenses are: -- -- * 'uiAttributeUpdates' @::@ 'HashMap' 'Text' 'AttributeValueUpdate' -- -- * 'uiConditionExpression' @::@ 'Maybe' 'Text' -- -- * 'uiConditionalOperator' @::@ 'Maybe' 'ConditionalOperator' -- -- * 'uiExpected' @::@ 'HashMap' 'Text' 'ExpectedAttributeValue' -- -- * 'uiExpressionAttributeNames' @::@ 'HashMap' 'Text' 'Text' -- -- * 'uiExpressionAttributeValues' @::@ 'HashMap' 'Text' 'AttributeValue' -- -- * 'uiKey' @::@ 'HashMap' 'Text' 'AttributeValue' -- -- * 'uiReturnConsumedCapacity' @::@ 'Maybe' 'ReturnConsumedCapacity' -- -- * 'uiReturnItemCollectionMetrics' @::@ 'Maybe' 'ReturnItemCollectionMetrics' -- -- * 'uiReturnValues' @::@ 'Maybe' 'ReturnValue' -- -- * 'uiTableName' @::@ 'Text' -- -- * 'uiUpdateExpression' @::@ 'Maybe' 'Text' -- updateItem :: Text -- ^ 'uiTableName' -> UpdateItem updateItem p1 = UpdateItem { _uiTableName = p1 , _uiKey = mempty , _uiAttributeUpdates = mempty , _uiExpected = mempty , _uiConditionalOperator = Nothing , _uiReturnValues = Nothing , _uiReturnConsumedCapacity = Nothing , _uiReturnItemCollectionMetrics = Nothing , _uiUpdateExpression = Nothing , _uiConditionExpression = Nothing , _uiExpressionAttributeNames = mempty , _uiExpressionAttributeValues = mempty } -- | There is a newer parameter available. Use /UpdateExpression/ instead. Note -- that if you use /AttributeUpdates/ and /UpdateExpression/ at the same time, -- DynamoDB will return a /ValidationException/ exception. -- -- This parameter can be used for modifying top-level attributes; however, it -- does not support individual list or map elements. -- -- The names of attributes to be modified, the action to perform on each, and -- the new value for each. If you are updating an attribute that is an index key -- attribute for any indexes on that table, the attribute type must match the -- index key type defined in the /AttributesDefinition/ of the table description. -- You can use /UpdateItem/ to update any nonkey attributes. -- -- Attribute values cannot be null. String and Binary type attributes must have -- lengths greater than zero. Set type attributes must not be empty. Requests -- with empty values will be rejected with a /ValidationException/ exception. -- -- Each /AttributeUpdates/ element consists of an attribute name to modify, along -- with the following: -- -- /Value/ - The new value, if applicable, for this attribute. -- -- /Action/ - A value that specifies how to perform the update. This action is -- only valid for an existing attribute whose data type is Number or is a set; -- do not use 'ADD' for other data types. -- -- If an item with the specified primary key is found in the table, the -- following values perform the following actions: -- -- 'PUT' - Adds the specified attribute to the item. If the attribute already -- exists, it is replaced by the new value. -- -- 'DELETE' - Removes the attribute and its value, if no value is specified for 'DELETE'. The data type of the specified value must match the existing value's -- data type. -- -- 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. -- -- '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, with a value of '3'. -- -- If the existing data type is a set, and if /Value/ is also a set, then /Value/ -- is appended 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, /Value/ must also be a set of strings. -- -- If no item with the specified key is found in the table, the following -- values perform the following actions: -- -- 'PUT' - Causes DynamoDB to create a new item with the specified primary key, -- and then adds the attribute. -- -- 'DELETE' - Nothing happens, because attributes cannot be deleted from a -- nonexistent item. The operation succeeds, but DynamoDB does not create a new -- item. -- -- 'ADD' - Causes DynamoDB to create an item with the supplied primary key and -- number (or set of numbers) for the attribute value. The only data types -- allowed are Number and Number Set. -- -- 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. uiAttributeUpdates :: Lens' UpdateItem (HashMap Text AttributeValueUpdate) uiAttributeUpdates = lens _uiAttributeUpdates (\s a -> s { _uiAttributeUpdates = a }) . _Map -- | A condition that must be satisfied in order for a conditional update to -- succeed. -- -- An expression can contain any of the following: -- -- Boolean functions: 'attribute_exists | attribute_not_exists | contains |begins_with' -- -- These function names are case-sensitive. -- -- Comparison operators: ' = | <> | < | > | <= | >= | BETWEEN | IN' -- -- Logical operators: 'AND | OR | NOT' -- -- For more information on condition expressions, go to <http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html Specifying Conditions> -- in the /Amazon DynamoDB Developer Guide/. uiConditionExpression :: Lens' UpdateItem (Maybe Text) uiConditionExpression = lens _uiConditionExpression (\s a -> s { _uiConditionExpression = a }) -- | There is a newer parameter available. Use /ConditionExpression/ instead. Note -- that if you use /ConditionalOperator/ and / ConditionExpression / at the same -- time, DynamoDB will return a /ValidationException/ exception. -- -- This parameter does not support lists or maps. -- -- A logical operator to apply to the conditions in the /Expected/ map: -- -- 'AND' - If all of the conditions evaluate to true, then the entire map -- evaluates to true. -- -- 'OR' - If at least one of the conditions evaluate to true, then the entire map -- evaluates to true. -- -- If you omit /ConditionalOperator/, then 'AND' is the default. -- -- The operation will succeed only if the entire map evaluates to true. uiConditionalOperator :: Lens' UpdateItem (Maybe ConditionalOperator) uiConditionalOperator = lens _uiConditionalOperator (\s a -> s { _uiConditionalOperator = a }) -- | There is a newer parameter available. Use / ConditionExpression / instead. -- Note that if you use /Expected/ and / ConditionExpression / at the same time, -- DynamoDB will return a /ValidationException/ exception. -- -- This parameter does not support lists or maps. -- -- A map of attribute/condition pairs. /Expected/ provides a conditional block -- for the /UpdateItem/ operation. -- -- Each element of /Expected/ consists of an attribute name, a comparison -- operator, and one or more values. DynamoDB compares the attribute with the -- value(s) you supplied, using the comparison operator. For each /Expected/ -- element, the result of the evaluation is either true or false. -- -- If you specify more than one element in the /Expected/ map, then by default -- all of the conditions must evaluate to true. In other words, the conditions -- are ANDed together. (You can use the /ConditionalOperator/ parameter to OR the -- conditions instead. If you do this, then at least one of the conditions must -- evaluate to true, rather than all of them.) -- -- If the /Expected/ map evaluates to true, then the conditional operation -- succeeds; otherwise, it fails. -- -- /Expected/ contains the following: -- -- /AttributeValueList/ - 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 http://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters>. -- -- For type Binary, DynamoDB treats each byte of the binary data as unsigned -- when it compares binary values, for example when evaluating query expressions. -- -- /ComparisonOperator/ - A comparator for evaluating attributes in the /AttributeValueList/. When performing the comparison, DynamoDB uses strongly consistent reads. -- -- 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 datatypes, 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 specified -- 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 datatypes, 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 specified 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 specified 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 specified 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 specified 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 specified 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 datatypes, -- including lists and maps. -- -- 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 datatypes, -- including lists and maps. -- -- 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 within two sets. -- -- /AttributeValueList/ can contain one or more /AttributeValue/ elements of type -- String, Number, or Binary (not a set type). These attributes are compared -- against an existing set type attribute of an item. If any elements of the -- input set are present in 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 specified 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"]}' -- -- For usage examples of /AttributeValueList/ and /ComparisonOperator/, see <http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/LegacyConditionalParameters.html Legacy Conditional Parameters> in the /Amazon DynamoDB Developer Guide/. -- -- For backward compatibility with previous DynamoDB releases, the following -- parameters can be used instead of /AttributeValueList/ and /ComparisonOperator/: -- -- /Value/ - A value for DynamoDB to compare with an attribute. -- -- /Exists/ - A Boolean value that causes DynamoDB to evaluate the value before -- attempting the 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 condition evaluates to -- true; otherwise the condition evaluate to false. -- -- 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 condition evaluates to true. If the value is found, despite -- the assumption that it does not exist, the condition evaluates to false. -- -- Note that the default value for /Exists/ is 'true'. -- -- The /Value/ and /Exists/ parameters are incompatible with /AttributeValueList/ -- and /ComparisonOperator/. Note that if you use both sets of parameters at once, -- DynamoDB will return a /ValidationException/ exception. uiExpected :: Lens' UpdateItem (HashMap Text ExpectedAttributeValue) uiExpected = lens _uiExpected (\s a -> s { _uiExpected = a }) . _Map -- | One or more substitution tokens for simplifying complex expressions. The -- following are some use cases for using /ExpressionAttributeNames/: -- -- To shorten an attribute name that is very long or unwieldy in an -- expression. -- -- 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 expression: -- -- 'order.customerInfo.LastName = "Smith" OR order.customerInfo.LastName ="Jones"' -- -- Now suppose that you specified the following for /ExpressionAttributeNames/: -- -- '{"#name":"order.customerInfo.LastName"}' -- -- The expression can now be simplified as follows: -- -- '#name = "Smith" OR #name = "Jones"' -- -- For more information on expression attribute names, go to <http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.AccessingItemAttributes.html Accessing ItemAttributes> in the /Amazon DynamoDB Developer Guide/. uiExpressionAttributeNames :: Lens' UpdateItem (HashMap Text Text) uiExpressionAttributeNames = lens _uiExpressionAttributeNames (\s a -> s { _uiExpressionAttributeNames = a }) . _Map -- | 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, go to <http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html SpecifyingConditions> in the /Amazon DynamoDB Developer Guide/. uiExpressionAttributeValues :: Lens' UpdateItem (HashMap Text AttributeValue) uiExpressionAttributeValues = lens _uiExpressionAttributeValues (\s a -> s { _uiExpressionAttributeValues = a }) . _Map -- | 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 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. uiKey :: Lens' UpdateItem (HashMap Text AttributeValue) uiKey = lens _uiKey (\s a -> s { _uiKey = a }) . _Map uiReturnConsumedCapacity :: Lens' UpdateItem (Maybe ReturnConsumedCapacity) uiReturnConsumedCapacity = lens _uiReturnConsumedCapacity (\s a -> s { _uiReturnConsumedCapacity = a }) -- | A value that 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. uiReturnItemCollectionMetrics :: Lens' UpdateItem (Maybe ReturnItemCollectionMetrics) uiReturnItemCollectionMetrics = lens _uiReturnItemCollectionMetrics (\s a -> s { _uiReturnItemCollectionMetrics = a }) -- | Use /ReturnValues/ if you want to get the item attributes as they appeared -- either before or after they were 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' - If /UpdateItem/ overwrote an attribute name-value pair, then the -- content of the old item is returned. -- -- 'UPDATED_OLD' - The old versions of only the updated attributes are returned. -- -- 'ALL_NEW' - All of the attributes of the new version of the item are -- returned. -- -- 'UPDATED_NEW' - The new versions of only the updated attributes are returned. -- -- uiReturnValues :: Lens' UpdateItem (Maybe ReturnValue) uiReturnValues = lens _uiReturnValues (\s a -> s { _uiReturnValues = a }) -- | The name of the table containing the item to update. uiTableName :: Lens' UpdateItem Text uiTableName = lens _uiTableName (\s a -> s { _uiTableName = a }) -- | An expression that defines one or more attributes to be updated, the action -- to be performed on them, and new value(s) 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 -- attribute 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. -- -- '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 Number and 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, go to <http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.Modifying.html Modifying Items andAttributes> in the /Amazon DynamoDB Developer Guide/. uiUpdateExpression :: Lens' UpdateItem (Maybe Text) uiUpdateExpression = lens _uiUpdateExpression (\s a -> s { _uiUpdateExpression = a }) data UpdateItemResponse = UpdateItemResponse { _uirAttributes :: Map Text AttributeValue , _uirConsumedCapacity :: Maybe ConsumedCapacity , _uirItemCollectionMetrics :: Maybe ItemCollectionMetrics } deriving (Eq, Read, Show) -- | 'UpdateItemResponse' constructor. -- -- The fields accessible through corresponding lenses are: -- -- * 'uirAttributes' @::@ 'HashMap' 'Text' 'AttributeValue' -- -- * 'uirConsumedCapacity' @::@ 'Maybe' 'ConsumedCapacity' -- -- * 'uirItemCollectionMetrics' @::@ 'Maybe' 'ItemCollectionMetrics' -- updateItemResponse :: UpdateItemResponse updateItemResponse = UpdateItemResponse { _uirAttributes = mempty , _uirConsumedCapacity = Nothing , _uirItemCollectionMetrics = Nothing } -- | A map of attribute values as they appeared before the /UpdateItem/ operation. -- This map only appears if /ReturnValues/ was specified as something other than 'NONE' in the request. Each element represents one attribute. uirAttributes :: Lens' UpdateItemResponse (HashMap Text AttributeValue) uirAttributes = lens _uirAttributes (\s a -> s { _uirAttributes = a }) . _Map uirConsumedCapacity :: Lens' UpdateItemResponse (Maybe ConsumedCapacity) uirConsumedCapacity = lens _uirConsumedCapacity (\s a -> s { _uirConsumedCapacity = a }) uirItemCollectionMetrics :: Lens' UpdateItemResponse (Maybe ItemCollectionMetrics) uirItemCollectionMetrics = lens _uirItemCollectionMetrics (\s a -> s { _uirItemCollectionMetrics = a }) instance ToPath UpdateItem where toPath = const "/" instance ToQuery UpdateItem where toQuery = const mempty instance ToHeaders UpdateItem instance ToJSON UpdateItem where toJSON UpdateItem{..} = object [ "TableName" .= _uiTableName , "Key" .= _uiKey , "AttributeUpdates" .= _uiAttributeUpdates , "Expected" .= _uiExpected , "ConditionalOperator" .= _uiConditionalOperator , "ReturnValues" .= _uiReturnValues , "ReturnConsumedCapacity" .= _uiReturnConsumedCapacity , "ReturnItemCollectionMetrics" .= _uiReturnItemCollectionMetrics , "UpdateExpression" .= _uiUpdateExpression , "ConditionExpression" .= _uiConditionExpression , "ExpressionAttributeNames" .= _uiExpressionAttributeNames , "ExpressionAttributeValues" .= _uiExpressionAttributeValues ] instance AWSRequest UpdateItem where type Sv UpdateItem = DynamoDB type Rs UpdateItem = UpdateItemResponse request = post "UpdateItem" response = jsonResponse instance FromJSON UpdateItemResponse where parseJSON = withObject "UpdateItemResponse" $ \o -> UpdateItemResponse <$> o .:? "Attributes" .!= mempty <*> o .:? "ConsumedCapacity" <*> o .:? "ItemCollectionMetrics"