Find version of Oracle database instance
SELECT * FROM V$VERSION
or
SELECT version FROM V$INSTANCE
Find the current ORACLE_SID you are logged in
sqlplus sys as sysdba;
select name from v$database;
select instance from v$thread;
select ora_database_name from dual;
Find the current schema name you are logged in
select sys_context('userenv','instance_name') from dual;
select user from dual;
select * from global_name;
Find location of alert logs, alert log file name will be alert_ORACLE_SID.log
show parameter background;
To find out the location of diagnostic info like trace , logs etc.
select * from v$diag_info;
