Some questions from database newbie

A while ago our database person left us and in the interim until a new person is hired I got stuck with looking after the databases on top of everything else. After several weeks of crash course in databases, SQL, Oracle, etc (eg like having a real life test of my predecessor's backup strategies), I have come up with a number of questions which are probably quite basic but haven't been able to locate in the mounds of reference materials, and I thought I ask here. (I have a couple of Oracle contacts on campus, but am saving them for the more stressful questions--- like 'My database just crashed. What should I do?')

Running Oracle 7.3.3 on Digital Unix.

1. The existing database code makes reference to a table sys.dual. I can't find any references to this table in my books, and this table seems to behave really strangely: eg describe sys.dual lists a single column DUMMY, yet select user from sys.dual; returns my userid. What's going on here?
2. After spending close to an hour trying to enter a stored procedure in sqlplus, I eventually learned that I need to terminate the definition with a '/', although can't find any explanation of this in books. Did see something about terminating with a '.', which actually succeeds in terminating (ie no longer left with Oracle prompting me for rest of command), but also seems to discard what I did. Since a ';' seems sufficient to terminate most every other command, I there's some logic to all this that I am missing.
3. In my crash recovery, it seems that a sequence that was used to ensure the primary key of a table got reset several days. I assume this is because I restored from a several day old cold backup and then imp'ed fromuser= the user who owns all the important tables from a full export done shortly before the crash (which I think is just a lucky coincidence, but who knows). At least, I think that is what happened, but it also seemed to only have happened to a single sequence. (Fortunately, the affected table is not referenced by any other table and is actually somewhat redundant, so I don't believe manually massaging the data to make primary key unique again will be a problem).
4. Does this hypothesis seem reasonable? I.e, would an imp fromuser=dba not update the sequences owned by user? Should I have the misfortune of being here when this database crashes again, is there a better way to do the import?
5. I need to reset the sequence (set it ahead 100 or so). The best way I see of doing that is to alter sequence's increment to something like 100, call nextval for the sequence, then reset increment to 1. Is there an easier way?

Thanks in advance for any help I receive.

Tom Payerle

Dept of Physics				payerle_at_physics.umd.edu
University of Maryland			(301) 405-6973
College Park, MD 20742-4111		Fax: (301) 314-9525

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Tom Payerle

Dept of Physics				payerle_at_physics.umd.edu
University of Maryland			(301) 405-6973
College Park, MD 20742-4111		Fax: (301) 314-9525