2 questions: data block corruption + good oracle troubleshoooting sites

Hello.

2 questions:

• I'm having the following error when accessing Oracle using SQL Navigator:

ORA-01578: ORACLE data block corrupted (file # 1, block # 40401) ORA-01110: data file 1: '/home/oracle/data1/oradata/ORCL/system01.dbf'

I know that there is data block corruption (duh!) and that i have to restore the segment with block # 40401, but i don't know if this recovering of the segment will cause loss of data. Is that the case?

• Can anyone point me to some good oracle/sql sites? You know, those that you go to when you have a doubt or are looking for faqs, one that it's not limited to theory. I've been brwosing around http://technet.oracle.com but i'd like some more "solutions".

Thanks in advance...

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jpa