Structured Query Language (SQL) is simply a
language to communicate with computers. It's quite
an old language in terms of modern computers
history.
One of the first implementation of higher
abstraction level language was DEDUCOM (Deductive
Communicator). It was operating around the year
1965. The program DEDUCOM was written in LISP. This
deductive program had capacity for 68 facts and it
was able to answer 10 questions.
The deductive programs development was directed
towards increasing capacity of the whole systems to
absorb higher number of the input facts.
The concept became base for the idea of programs
where input is given in simple queries. The result
were programs allowing to answer questions by ad-hoc
search programs construction.
This type of programs construction had
complications in the correct answer search
implementation. Some queries doesn't gives answers
and some do in the case of correct facts sorting.
The DEDUCOM program solved this by propositional
calculus usage. Implementation complications arrised
when the facts had to be transformed into the
logical equivalent in propositional calculus and it
was necessary to input many redundant facts. In any
case DEDUCOM became proof of concept for these
programs.
Interestingly the DEDUCOM was the result of
artifical intelligence research in LISP language.
