Translating natural language queries (NLQ) into structured query language
(SQL) in interfaces to relational databases is a challenging task that has been
widely studied by researchers from both the database and natural language
processing communities. Numerous works have been proposed to attack the natural
language interfaces to databases (NLIDB) problem either as a conventional
pipeline-based or an end-to-end deep-learning-based solution. Nevertheless,
regardless of the approach preferred, such solutions exhibit black-box nature,
which makes it difficult for potential users targeted by these systems to
comprehend the decisions made to produce the translated SQL. To this end, we
propose xDBTagger, an explainable hybrid translation pipeline that explains the
decisions made along the way to the user both textually and visually. We also
evaluate xDBTagger quantitatively in three real-world relational databases. The
evaluation results indicate that in addition to being fully interpretable,
xDBTagger is effective in terms of accuracy and translates the queries more
efficiently compared to other state-of-the-art pipeline-based systems up to
10000 times.Comment: 20 pages, 6 figures. This work is the extended version of
arXiv:2101.04226 that appeared in PVLDB'2