1. A method comprising: receiving a query that specifies one or more XML nodes that are binary-encoded; in response to receiving the query, requesting binary-encoded XML data from one or more data sources; receiving at least a subset of the binary-encoded XML data; determining, from node information associated with the subset of the binary-encoded XML data, that a particular node, of the one or more XML nodes, is simple, wherein a node is simple if the node has no child elements and no associated attributes; and in response to determining that the particular node is simple, identifying the scalar value of the particular node in the subset of the binary-encoded XML data.