asterisk users - Oct 2011 - Asterisk 1.8 and CDR Mysql: Unqiue ID and if any commands required in extensions.conf

Hi All;

I am using asterisk version 1.8 and I selected CDR mysql from the menuselect
when I was doing the compilation and installation.

How can I know if the unique id will be added to the cdr, and how I can know
which information will be logged, also from where I can new field to be logged
and its location (before or after specific field)?

One more thing: to have cdr, then do I have to write any syntax in the
extensions.conf or there is a defualt fields will be logged without need to
write any syntax? For example I found the below lines and I need to know if I
have to add them or not (actually it might be used only for trunk version which
I am not use but I need to confirm):

some_context
;dial trunk
exten => _X.,1,Dial(SIP/trunk/${EXTEN})

;exten h must be in same context!
exten => h,1,noop("extended CDR")
exten => h,n,set(CDR(hangupcause)=${HANGUPCAUSE}) ; hangupcause
exten => h,n,set(CDR(peerip)=${CHANNEL(peerip)}) ; like 10.0.0.5 if behind
nat
exten => h,n,set(CDR(recvip)=${CHANNEL(recvip)}) ; like 194.79.52.192 -
public ip
exten => h,n,set(CDR(from)=${CHANNEL(from)}) ; like sip:1111 at sip.proxy.cz
exten => h,n,set(CDR(uri)=${CHANNEL(uri)}) ; like sip:1111 at 10.0.0.5
exten => h,n,set(CDR(useragent)=${CHANNEL(useragent)}) ; useragent like
Aastra_57i
exten => h,n,set(CDR(codec1)=${CHANNEL(audioreadformat)}) ; codec *
exten => h,n,set(CDR(codec2)=${CHANNEL(audiowriteformat)}) ;
exten => h,n,set(CDR(llp)=${CHANNEL(rtpqos,audio,local_lostpackets)}) ; lost
packets by local end **
exten => h,n,set(CDR(rlp)=${CHANNEL(rtpqos,audio,remote_lostpackets)}) ; lost
packets by remote end
exten => h,n,set(CDR(ljitt)=${CHANNEL(rtpqos,audio,local_jitter)}) ; the same
for jitter
exten => h,n,set(CDR(rjitt)=${CHANNEL(rtpqos,audio,remote_jitter)})

Regards
Bilal