CPE 365 Professor M. Liu -- FREQUENTLY ASKED QUESTIONS
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Q: I'm trying to log-in to Oracle 10g with SQL*Plus, and keep
   running into the following error message:
     ERROR:
     ORA-28000: the account is locked
A: The problem you reported  happens when you have gotten dropped from a
   SQL*Plus session to which you are still connected.  You can avoid this
   problem by making sure that you EXIT from sql*Plus before logging out
   of vogon.  Sometimes the problem cannot be avoided if your connection
   is cut off by the network or the system itself.

   To get out of your jam so that you can connect to Oracle again,  you
   can do this:
   While in vogon, enter this Linux command:
        ps -ux
   This will show you the Linux processes currently running in your
   account, something like this:
      USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
      mliu       371  0.0  0.1  15028  2060 ?        SN   09:59   0:00 sshd:
      mliu@pts/
      mliu       373  1.0  0.1   8920  1544 pts/12   SNs  09:59   0:00 -bash
      mliu       481  0.0  0.0   8588   904 pts/12   RN+  09:59   0:00 ps -ux

   Chances are if you got the error you reported ,you have a sqlplus
   process active.  So look for a line of the output where the value
   under the COMMAND column is sqlplus.  The process's ID is then the
   value on the same row under the column heading PID.

   Now, you can stop that process by entering this command in Linux:
      kill  -9  <PID>
   replacing <PID> with the aforementioned process ID.

Q: I think it would be helpful to have more problems on homework assignments.
   I have found when learning a new language paradigm (e.g. linear, functional,
   DML) that it helps to do a lot of simple problems and gradually work up to more
   difficult ones. 
   If you don't want to assign them to the whole class -- extra problems that
   don't count for a grade would be fine too.  
A: Different students have different levels of needs for practice.  I believe
   that the examples we discussed in class, coupled with the lab problems (whose
   solutions are posted) should be sufficient for the understanding of the topics that
   we cover.
   If you need more practice, I recommend this:
   - The textbook by Ullman and Widom has examples.  I would especially
     recommend taking a look at the reference book Oracle 9i Programming by Sunderraman (or
     earlier editions), which has many examples using the databases that we have been
     using in class.
   - The tutorials section on the course page has links to some tutorials.
   - There are tutorials on the web on various topics.  Database is a
     well-studied field and information is plentiful, although you should be careful with
     selecting the good information.
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A: I'm wondering if you would put the solutions for the examples that we skip
   in class. I think it would help me alot to see if i have the example answers right
   before going on to do the lab problems. 
Q: I am afraid I cannot remember which examples have been skipped.  I leave
   out the answers from the lecture notes that I post so that there will be motivation
   for students to pay attention to our discussion in class.
   You are always welcome to ask me questions in the lab or during my office
   hours.  If you don't ask, I assume you know.  
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