This paper describes a prototypal system which has been implemented in order to explore the possibility of using topological integrity constraints as interactive drivers to support spatial database updates. The idea of using constraints to drive updates is applied also in traditional (non-spatial) databases; for example, in order to preserve referential integrity, the user can be forced to select a value in a given set, instead of permitting him to write an arbitrary value and then checking that the value satisfies the constraint. This idea seems to be much more relevant in spatial databases, both because spatial data possesses a much richer set of constraints, and because spatial updates are more complex and error-prone than traditional, alphanumeric updates. The paper first defines formally a rather general spatial database environment with integrity constraints, then describes a prototypal system which has been built in order to explore the practical effectiveness of the general idea (the feasibility includes performance, because the constraints are used during the interaction with the user). The prototype which has been implemented is capable of driving updates on simple polygons and uses a restricted class of integrity constraints; however, it is sufficiently powerful to demonstrate the feasibility of the approach.