- NLS settings
NLS settings supports the globalization of the db instance. It has variety of parameters like NLS_LANGUAGE, NLS_TERRITORY etc. The settings can be done at three level database, instance and session level. Session level takes precedance over the other two. The NLS settings are stored in
NLS_DATABASE_PARAMETERS,
NLS_INSTANCE_PARAMETERS,
NLS_SESSION_PARAMETERS.
The session can be set as
ALTER SESSION SET parameter_name = 'parameter_value'
Example:
ALTER SESSION SET NLS_TERRITORU = 'AMERICA'.
NLS settings governs lots of db settings like date, time format, calendar, start of week, etc
- LOCK TABLE
An update of any table can be prevented by putting lock on it using below command.
LOCK TABLE hr.per_medical_assessments IN EXCLUSIVE MODE;
The lock is removed by either a coomit or a rollback
- CALUCLATING AGE
Age can be calculated as
FLOOR ( MONTHS_BETWEEN(trunc(sysdate) , ppx.DATE_OF_BIRTH)/12) age
