[Lazarus] Web development and XML database (Mattias)

[Santiago A.]

El 16/11/2011 16:36, Graeme Geldenhuys escribió:
> But yes, SQL queries can take long too - depending on what it must do.
> I have worked on project where we had to do data conversion from a IBM
> mainframe system to a Intel based SQL Server 2000 database. A full
> data conversion had to be run on Friday's, and normally only ended on
> Monday morning (if no failures occurred). That's 2.5-3.0 days
> continuous running, resulting in a 8GB SQL Server database. But this
> is an extreme case. :)

Updates, inserts and deletes in RDBM are usually slower than many other
solutions due transaction tracking, integrity etc. Where retrieving data
I think that RDBM are much better where dealing with a lot of data, more
flexible and at least as faster as any other solutions. Obviously the
advantages of a RDBM have a price, particularly when updating. But IMHO
the advantages overcome disadvantages, particularly when dealing with a
lot of data. Nevertheless, for small amount of data and/or concrete
searches or updates you can design a particular solution that works better.

When we must move a lot of data, we remove all triggers, indexes, and
foreignkey controls. Then, after moving all data, we activate indexes,
triggers, foreign keys etc. Depending on the RDBM you  benchmark if it
is faster to commit small transactions or large transactions (usually
large transactions). In some RDBM you can even disable transactions. Of
course this options are for admin management, like migrations, massive
structure upgrade etc.

Sure that for small amount of data and single user (e.g. configuration
files), XML is a good option.

-- 
Saludos

Santago A.
svaa at ciberpiula.net