-- | 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
-- <http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ReservedWords.html 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 on expression attribute names, see
-- <http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.AccessingItemAttributes.html Accessing Item Attributes>
-- in the /Amazon DynamoDB Developer Guide/.
qExpressionAttributeNames :: Lens' Query (HashMap Text Text)
qExpressionAttributeNames = lens _qExpressionAttributeNames (\ s a -> s{_qExpressionAttributeNames = a}) . _Default . _Map
qExpressionAttributeNames :: Lens' Query (HashMap Text Text)
qExpressionAttributeNames = lens _qExpressionAttributeNames (\ s a -> s{_qExpressionAttributeNames = a}) . _Default . _Map
qExpressionAttributeNames = lens _qExpressionAttributeNames (\ s a -> s{_qExpressionAttributeNames = a}) . _Default . _Map