Proof of serializability for semistructured databases

Semistructured databases require tailor-made concurrency control mechanisms since traditional solutions for the relational model have been shown to be inadequate. Such mechanisms need to take full advantage of the hierarchical structure of semistructured data, for instance allowing concurrent updates of subtrees of, or even individual elements in, XML documents. We present a general framework to study concurrency control. This framework is documentindependent in the sense that two schedules of semistructured transactions are equivalent if they are equivalent on all possible documents. We prove that it is decidable in polynomial time and space whether two given schedules in this framework are equivalent. This also solves the serializability for semistructured schedules polynomially in the number of actions and exponentially in the number of transactions.