1 research outputs found
Can One Escape Red Chains? Regular Path Queries Determinacy is Undecidable
For a given set of queries (which are expressions in some query language)
, and for another query we say
that determines if -- informally speaking -- for every
database , the information contained in the views
is sufficient to compute . Query
Determinacy Problem is the problem of deciding, for given and
, whether determines . Many versions of this problem,
for different query languages, were studied in database theory. In this paper
we solve a problem stated in [CGLV02] and show that Query Determinacy Problem
is undecidable for the Regular Path Queries -- the paradigmatic query language
of graph databases