Re: [Firefly-dev] Patrons management

[firefly-dev]

That patron.xml was a mook up of a idea I had. It is not going to be
something that stays. I did not even mean for it to go into cvs. I know
what you are saying about how slow it is. What would you like to discuss
about OOP?
John Hornbeck


On Mon, 2003-03-31 at 16:57, address@hidden wrote:
> Hi,
> 
> I would like to ask you one thing about patrons management.
> In the cvs repository there is a file called patron.xml whose purpose is
> still not very clear to me.
> I really hope you do not intend to manage patrons with xml files, it
> would be a nightmare. 
> 
> Just think about a simple loan, in the db you have to store the user_id
> of the patron who loaned the book, and where do you take it from if it
> is not in the db ?  from the xml file ?  
> This mean that you have to parse the xml file(which require to create a
> sax parser to go through the file until it founds what we need, or even
> worse create a dom representation of the entire file in the memory) and
> put in the query the results of the parsing operation.
> This is *terribly* slower than a simple db operation, at least a million
> time to be optimistic, and don't forget the overhead caused by the
> network connection(and the encriptions of the data with ssl).
> Also you must take care of concurrent access to files, what if two of
> the staff modify at the same time a patron's details ? In the worst case
> this may empty or erase the file...
> 
> I use often xml at work and it sure has many uses but it can't and must
> not replace a db.
> 
> Actually I see two possible uses for xml in this project:
> 
> 1. an hipothetical "registry" that serves as a glue between core app and
> plugins. 
> This is absolutely required if a plugin is written in a different
> language than the core, plugins and core can exchange data between
> themselves in an xml format (soap, wddx etc...), without requiring CORBA
> or stuff like that.
> 
> 2. we can retrieve data from the db in an xml format suitable to be
> transformed with an xslt stylesheet(this can be easily been done with
> openjade but I don't think windows has something like that...) in the
> formats we want.
> 
> Another thing, considering the features of this app and especially its
> "modular" nature, I would like to discuss with you about a more object
> oriented development approach.
> 
> 
> Let me know what do you think.
> 
> 
> Marco
> 
> 
> 
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-- 
John Hornbeck <address@hidden>