Retrieves rows in hierarchical order.e.g. select empno, ename from emp where.
"connect by prior" is clause which is used in hierarchical queries.Example
start with job='PRESIDENT'
connect by prior empno=mgr;
ROWID is a pseudo column generated at the run time(during inserting value). Its a hexadecimal value which is unique identification for each record
%IS OPEN,%FOUND,%NOT FOUND,%ROW COUNT
Database Link is a named path through which a remote database can be accessed
Correlated subquery is the subquery, where the subquery has been executed for the every row processed by the parent statement.