  We propose a new approach to querying graph databases. Our approach balances
competing goals of expressive power, language clarity and computational
complexity. A distinctive feature of our approach is the ability to express
properties of minimal (e.g. shortest) and maximal (e.g. most valuable) paths
satisfying given criteria. To express complex properties in a modular way, we
introduce labelling-generating ontologies. The resulting formalism is
computationally attractive - queries can be answered in non-deterministic
logarithmic space in the size of the database.
