About topologies
Topologies are collections of one or more feature classes in a geodatabase, with rules that model how the features share coincident geometry. A typical example of this is a topology containing public roads, parcels of land, and buildings as polygons. Parcels should not be allowed to overlap - neither should public roads and parcels - and buildings should be contained within a parcel. Topologies allow these types of rules to be defined and provide validation tools to identify features that violate the rules, as well as features that are explicitly allowed to violate the rules.
See Also:
Creating a topology in the geodatabaseChecking for topology error features in a geodatabase topology
Listening to the OnValidate event for a geodatabase topology