1. A method comprising: receiving, at a server via web service communications, client web service messages from a client; wherein receiving the client web service messages comprises: receiving a first client web service message to request a connection to the server; receiving a second client web service message that encapsulates an XQuery expression that conforms to the XQuery language; at the server, extracting the XQuery expression from the second client web service message; at the server, executing the XQuery expression against XML data; sending, from the server to the client via web service communications, a server web service message; wherein the server web service message contains a sequence of items; wherein the sequence of items contains at least part of results from execution of the XQuery expression; wherein the method is performed by one or more computing devices.