Abstract
This paper concerns an expansion of first-order Belnap-Dunn logic, named
BD$^{\supset,F}_\bot$, and an application of this logic in the area of
relational database theory.
The notion of a relational database, the notion of a query applicable to
a relational database, and several notions of an answer to a query with
respect to a relational database are considered from the perspective of
this logic, taking into account that a database may be an inconsistent
database or a database with null values.
The chosen perspective enables among other things the definition
of a notion of a consistent answer to a query with respect to a possibly
inconsistent database without resort to database repairs.
For each of the notions of an answer considered, being an answer to a
query with respect to a database of the kind considered is decidable.