page contains up to date information on LEAP. What it is, what
you can and cannot do with it, who uses it, what they use it for,
and much more.
What is LEAP?
What does LEAP contain?
What is LEAP not?
Potential uses for LEAP
Brief History of LEAP
New Features in 1.2.3
New features coming in 1.3
Versions for new features....
Release dates for versions
Source code availability
LEAP is a relational database management system (RDBMS). LEAP
supports relations, has a query language by which information can
be extracted from the relations, and has a support environment for
users querying the data. At such a basic level, LEAP is just
like the large, complex, mission critical RDBMS offerings from Sybase,
Oracle and IBM.
Clearly, however, it isn't as powerful as these heavyweight offerings.
LEAP is different in the sense that it was originally written
as an educational tool by a student.
The query language makes LEAP what it is. It is a full implementation
of the relational algebra, which is the theoretical basis for
far more advanced query languages such as SQL. When studying
database theory, students will generally encounter the relational
algebra along with the relational calculus as means by which the behavioural
component of the relational model can be implemented.
implementation of the algebra used in LEAP is very similair
to that used by many of the popular educational texts on Databases,
notably: C.J.Date's "An introduction to database systems";
and S.Stanczyk's "Theory and Practice of Relational Databases".
A sample session from LEAP, which
uses examples from these texts, is available.
has been incorporated into courses at a number of Universities around
the world. In providing students with a tool by which they can experiment
with the relational algebra, a course that can otherwise be rather
lacking in practical exercies, can be made far more interesting.
Further information can be found in the on-line version of the user
manual. Of course the user manual is included in the standard distribution
which can be downloaded.
can also see a demonstration of LEAP on the LEAP
does LEAP contain?
download LEAP, you'll get:
Full 'C' source code - well documented, well commented,
and freely available under the GNU
General Public License.
Three example databases from
well known educational text, including C.J Date and Stefan Stanczyk
Full html user documentation
Support for all popular Unix
variants, including Solaris, SunOS, HP-UX, AIX, Linux and more.
Pre-compiled 32 bit Windows 95/NT console binaries in the
is LEAP not?
The LEAP mailing list once received an e-mail from somebody
involved with the PostreSQL
publicity project, suggesting that LEAP was a duplication of
an effort already well advanced. LEAP is most certainly not
a fully fledged RDBMS, and has quite a different goal in mind to that
LEAP will always be an RDBMS geared to educational purposes.
If it ever reaches a point where it offers advanced features
such as locking, multi-users, transactions etc., then it will tackle
it from the perspective of a teaching tool.
who is after a heavy duty, free RDBMS, would be well advised
to look elsewhere, such as the PostreSQL
project, or the GNU
RDBMS system currently under development.
uses for LEAP
has been used, very successfully in the various courses on Databases
run at Oxford Brookes
University, and in an increasing number of establishments around
the world. Students have used LEAP to improve their understanding
of relational theory, and relational query languages. Universities
as far apart as France, New Zealand, Australia, Brazil, Sweden and
America have all informed me that they are using LEAP.
I am aware that some Postgraduate work with LEAP is going on
at a number of universities, but I have no further information at
this stage. As soon as I know, I'll update this page.
includes the full C source code, it's entirely free, which makes
it an ideal tool for more detailed study of database system theory.
history of LEAP
I originally wrote LEAP as an undergraduate project at Oxford
Brookes University. Whilst my supervisor jokingly described my
attempt at implementing an RDBMS as due to annoyance with Oracle,
it was more of an interest in the internals of database systems that
spurred the particular project.
The original ideas I had were far in excess of what was practical
in the time available. Therefore, I whittled it down to a suitably
small subset. LEAP had to be implemented on the resources most
appropriate, and a PC was convenient and available. Pascal licenses
were also available, and it just seemed to make sense to use them.
Once LEAP was "finished", I released a preliminary DOS only
version onto the Internet. I was then asked to present it to the 1995
Database course students, as a tool they might want to use. It was
well received. Some adventurous students used it (buggy as it then
was) to prove that their course-work on relational algebra
was correct. (Incidentally, they received an extra mark for the effort.)
submission and graduation, I continued to work on LEAP. Several
incarnations later LEAP is used by quite a few people worldwide
(rapidly approaching at least 100 different sites, to my knowledge),
and several establishments are actively investigating how to expand
it further. It has been completely rewritten in 'C', and supports
many more operating systems (principally Unix implementations).
It is also now freely available under the terms of the GNU
General Public License.
LEAP 1.2 has recently been released. The changes from 1.0
have made the system more efficient and portable, and provide a better
foundation for further development and enhancement.
For a full list of the latest developments and changes, take a look
at the news page. For a complete list of user-visible
changes, see the change history.
Wednesday, 3rd April, 2002
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