Type-Question

[Dermy sqlheld]

Hi all,

I have a table which looks like that:

CREATE TABLE `rr_radtour_tabelle` (
`fahrer` varchar(50) NOT NULL default '',
`strecke` dec(5,2) NOT NULL default '',
`gebrauchte_zeit` varchar(10) default NULL,
`bemerkung` varchar(255) default NULL,
`akt_gewicht` dec(5,2) NOT NULL default '',
`akt_groesse` dec(5,2) NOT NULL default '',
`akt_alter` int(10) NOT NULL default '',
`datum` varchar(255) NOT NULL default '',
`datum_eintrag` varchar(255) NOT NULL default '',
PRIMARY KEY (`fahrer`)
) type=MyISAM;

After a user entered his data in a formular, maybe strecke = 35,82, the value of strecke is set to 35.00
What am i doing wrong here? I thought dec(5,2) means, that numbers like 12345,12 are possible, but why is the part after the comma set to .00 ?!
A more generell question: How do i know, which types i need? If i want to make some calculations with values, can i take varchar for that or wont that work?

Many thanks in advance for replies,
Regards. Dermy.