  We study the relational to RDF data exchange problem, where the tar- get
constraints are specified using Shape Expression schema (ShEx). We investi-
gate two fundamental problems: 1) consistency which is checking for a given
data exchange setting whether there always exists a solution for any source
instance, and 2) constructing a universal solution which is a solution that
represents the space of all solutions. We propose to use typed IRI constructors
in source-to- target tuple generating dependencies to create the IRIs of the
RDF graph from the values in the relational instance, and we translate ShEx
into a set of target dependencies. We also identify data exchange settings that
are key covered, a property that is decidable and guarantees consistency.
Furthermore, we show that this property is a sufficient and necessary condition
for the existence of universal solutions for a practical subclass of
weakly-recursive ShEx.
