1. A method for computing differences between result sets for at least one query on a data store as the data store changes, wherein said data store stores a plurality of documents in at least one storage unit, including: identifying at least one change to be made to the data store; generating a first representation of at least one document of the plurality of documents, wherein the first representation represents a state of the at least one document before the at least one change is made; generating a second representation of at least one document of the plurality of documents, wherein the second representation represents a state of the at least one document after the at least one change is made, whereby said first representation and said second representation together represent at least all of the documents affected by the at least one change; and comparing the first and second representations to form a third representation that includes representations of the differences between said first and second representations.