Abstract: A client application may interact with a database service using a data interchange format with limited support for database data types or query representations. A map may be supported in the interchange format as a collection of name-value pairs. A database query may be parsed to form an abstract syntax tree. From the abstract syntax tree, a hierarchy of nested maps may be formed to represent the query, based on schemas mapping from regions of the abstract syntax tree to maps in the interchange format.

Abstract: A repository of key-value data may store a first object value having an internal structure of a hierarchy of sub-objects. The repository may receive a request to modify the first object, expressed as a projection of locations in the object to be updated and a function that, upon evaluation, returns values to be used to update the projected locations of the object. The repository may determine that the locations specified by the projections correspond to non-overlapping regions of the object and, based on the determination, update the object using the results of evaluating the function.