[Koha-devel] Re: Koha documents?

[Pat Eyler]

On Tue, 4 Nov 2003, Auvo Finne wrote:

> Hello Pat,
>
> I'm sorry maybe to make "stupid" questions, but I have no previous
> acquaintance with Koha and I don't want yet to dowload and install it.

No problem, although grabbing a copy to download and install is a pretty
easy (and painless) process.

>
> Let's make first a dichotomy: database subsystem, other parts of the Koha
> system.
> Do you have any description of the database objects? I suppose it's a
> relational database with tables etc. Which are the tables, fields, field
> definitions? Are there other database objects the Koha system uses? Views?
> Procedures? How are they named? Does koha.mysql give the answer?
>

Yes, we use MySQL to handle the RDBMS.  There aren't yet good documents on
the database design.  We aren't yet using views, stored procedures, or
similar DB functionality.

> Next there must be an interface (Naming of database objects constitutes part
> of this interface) between database and the other parts of the system?
> How is this designed and implemented? ODBC? If Koha is written in Perl and
> HTML,
> what is the communication mechanism with database?

You could consider Koha to use three tiers:

   presentation     (HTML generated from perl and HTML::Template)
   business logic   (Perl and DBI)
   database         (MySQL)


>
> Regarding system outside database, it seems as if it had three subsystems,
> namely intranet/librarian, circulation and OPAC.

the intranet portion is the librarian's interface and includes
circulation, acquisitions, and other internal tools.  the OPAC handles all
of the user/patron facing bits.

>
> What does C4 mean? Circulation module? Is circulation module part of the
> intranet/librarian subsystem?
>

C4 is actually a historical name from the early days of development.  The
initial developers joked that it was all liable to blow up, and nick named
the project C4 after the plastic explosive.  Fortunately, it has proven
quite stable in spite of the name.

> Are the user interfaces of these subsystems somehow separated as a subsystem
> itself? I suppose the UI is mainly written in HTML.

we separate the UI propper by using HTML::Template, which allows us to
create HTMLish templates which are then used by the business logic (Perl)
code to present data to the end user (library staff or patron)

>
> Are these subsystems replaceable? Can someone for example write a new
> circulation
> module (let's say in Java) and replace the old one without disturbing the
> functioning of other subsystems?

We've tried to be very modular.  It is hoped that our next version (2.2)
will be even more so.  I know that one library wrote a flash based circ
front-end for a demo to their library board.  It was quite spiffy, and
worked very well with the rest of Koha.

>
> We can also describe the deployment of subsystems and components according
> to machines
> (clients, servers). Does everything happen on one machine? DBMS on one
> machine,
> Apache and Perl on another? Are there any client components? Is Koha
> browser independent?

Koha proper runs on a single server (there's no reason you couldn't split
this out though -- again one of the 2.2 goals is to make this easier).
The only client component is a web browser.  We've tried to stay browser
independant, but there is currently a bit of javascript on some pages
which limits us a little bit -- I don't think most libraries would be
running the borwsers that don't play well with javascript.


>
> Is Perl the only programming language used? Java? JavaScript? What else?

Perl and (a little bit of) javascript are the only languages current;y
used.  There is no reason that some functionality couldn't be implemented
in another language if a library wanted to do so, but it's not certain
that any such new development would make it back into the core.


I hope this answers your questions.  If anyone else on the devel list
would like to expand on what I've written, please do.

-pate

>
> Greetings,
>
> Auvo
>
> ----- Original Message -----
> From: "Pat Eyler" <address@hidden>
> To: "Auvo Finne" <address@hidden>
> Cc: <address@hidden>
> Sent: Friday, October 31, 2003 6:14 PM
> Subject: Re: Koha documents?
>
>
> > On Fri, 31 Oct 2003, Auvo Finne wrote:
> >
> > > Dear Pat,
> >
> > Hello Auvo,
> >
> > >
> > > I act as a consult and codeveloper for the Tumaini University (Tanzania)
> library system.
> > > One of our alternatives is Koha. To seriously assess the suitability of
> Koha for Tumaini
> > > I would like to see some architectural documents.
> > >
> >
> > Sadly, architectural documents are one of the things that we don't have
> > in abundance.  If you were willing to spend a bit of time asking questions
> > (even just passing a list of questions you need answers to), we could
> > probably use them to build a set of answers/documents that might help.
> >
> > I'm answering this on the koha-devl mailing list as well, hopefully this
> > will help generate a bit more help for you as well.
> >
> > thanks,
> > -pate
> >
> > > We are applying the universal software development process. This process
> is very much
> > > architecture centric and uses several general or detailed diagrams.
> > >
> > > Does it exists any descriptions of Koha main components and their
> purposes, roles,
> > > interaction? Descriptionsof the use of programming languages in
> implementing these
> > > components? Etc.
> > >
> > > I'll be grateful if you could help me in getting some of these
> documents.
> > >
> > > Very best wishes,
> > >
> > > Auvo Finne
> > > Pitkakatu 44, Jyvaskyla, Finland
> > > +358 400 646 815
> > > address@hidden
> > >
> > >
>