I want to create a global trigger in oracle 11g ,which can be used for auditing of around 100 tables
Is there a reason you want to reinvent the wheel? Why not make use of Oracle's inbuilt auditing?
Oracle Base provides some basic info as to how to get started on Auditing:
Auditing can enabled by setting the AUDIT_TRAIL static parameter, which has the following allowed values.
AUDIT_TRAIL = { none | os | db | db,extended | xml | xml,extended }
The following list provides a description of each setting:
none or false - Auditing is disabled.
db or true - Auditing is enabled, with all audit records stored in the database audit trial (SYS.AUD$).
db,extended - As db, but the SQL_BIND and SQL_TEXT columns are also populated.
xml- Auditing is enabled, with all audit records stored as XML format OS files.
xml,extended - As xml, but the SQL_BIND and SQL_TEXT columns are also populated.
os- Auditing is enabled, with all audit records directed to the operating system's audit trail.
To enable auditing to database audit trail enable auditing to db
SQL> ALTER SYSTEM SET audit_trail=db,extended SCOPE=SPFILE;
System altered.
Shutdown & restart the db
SQL> SHUTDOWN
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> STARTUP
ORACLE instance started.
Now to audit SELECTS
, INSERTS
, UPDATES
, DELETES
by user cube
do this:
CONNECT sys/password AS SYSDBA
AUDIT ALL BY cube BY ACCESS;
AUDIT SELECT TABLE, UPDATE TABLE, INSERT TABLE, DELETE TABLE BY cube BY ACCESS;
The audited logs can be brought up by querying DBA_AUDIT_TRAIL
Further reading: