Pat Eyler wrote:
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.
we aren't using views/stored proc because mySQL doesn't handle them :-)
I think that's the best reason :-)
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)
you can divide the business logic in 2 subparts :
- .pl scripts that builds pages & call .pm for DB stuff
- .pm in C4 directory that are used for all DB access (except for admin
scripts : i did those script when i begun my involvement in Koha, and
had missed the .pm theory)
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_.
* Apache & Perl on differents servers, i don't know if it's
possible. If you need high scalability, you can always have X front end
servers (apache/perl), accessing 1 mySQL server (for data consistency),
and use dns round-robin on front-ends.
* _javascript_ is used in MARC editor, and not "a little". This is a
"must have".
--
Paul POULAIN
Consultant indépendant en logiciels libres
responsable francophone de koha (SIGB libre http://www.koha-fr.org)
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