Where are these functions are stored in Oracle database?

Question

Where is the function sysdate stored, and in what package, e.g:

select sysdate from dual;
select systimestamp from dual;

Also, take this query:

select sys.login_user,sys.database_name ,sys.sysevent from dual;

• what is sys here?
• Is it a package?
• where is this package stored?
• can I view the source(text) in this package please provide me the query?

Answer 1

sys is a schema. sysdate is a glovbally available variable containing the current date/time.

Answer 2

SYSDATE and SYSTIMESTAMP are functions in the STANDARD package owned by SYS. However, this is a special package and so you don't need to specify standard.sysdate (in fact, you can't!)

You can view this package like this:

select text
from   all_source
where owner='SYS'
and name='STANDARD'
and type = 'PACKAGE BODY'
order by line;