Get a list of tables: select table_name from all_tables.

Get a table's structure: desc tablename.

To see dates in a useful format alter session set nls_date_format='MM-DD-YYYY HH24:MI:SS';. Otherwise the default date format is: '7-Dec-2001'.

Oracle lives on the machine's filesystem at $ORACLE_BASE. $ORACLE_HOME is the root for the version that's currenlty being used.

When starting up a database, Oracle will look in =$ORACLE_HOME/dbs for the init.ora file.

JDBC connection URL format: jdbc:oracle:thin:@hostname:port:instance e.g. jdbc:oracle:thin:@poohpa:1521:CABOT. Oracle packages their jdbc driver in a .zip file (why should they follow the standards?), so look for a file named classes111.zip or something like that.

init.ora parameters: http://otn.oracle.com/doc/server.815/a67790/ch1.htm

"Oracle views": http://otn.oracle.com/doc/server.815/a67790/ch1.htm

To export a database use exp, exp help=y will give you help.

To see what database you're currently connected to, select name from u$database

In sqlplus, set timing on gives elapsed time for sql commands.

In-doubt xactions

If you end up with "in-doubt transactions" then you could be in a world of hurt since I've seen cases where they locked tables and hung around for days. You can't always force commits or rollbacks in OEM, so here's a recipe for getting rid of them when they happen (props to Kurt Stam):

Log in as sys sysdba.

select local_tran_id from dba_2pc_pending;
rollback force ' local id from previous query ';

This might not work; in that case you need to get a little more aggressive:

If the server is in "auto undo mode" then you'll need to put it in manual mode (comment out the entries in the init.ora that put it in auto mode - manual is the default) and bounce it.

Then connect as sys sysdba again and:

execute dbms_transaction.purge_lost_db_entry( ' local id from previous query ');
commit; (don't forget this!)

-- TobyCabot - 23 May 2002 - 08 Nov 2002