How do you find the numbert of rows in a Table ?

How do you find the numbert of rows in a Table ? 

A bad answer is count them (SELECT COUNT(*) FROM table_name)
A good answer is :-
'By generating SQL to ANALYZE TABLE table_name COUNT STATISTICS by querying Oracle System Catalogues (e.g. USER_TABLES or ALL_TABLES).
The best answer is to refer to the utility which Oracle released which makes it unnecessary to do ANALYZE TABLE for each Table individually.

What is the maximum buffer size that can be specified using the DBMS_OUTPUT.ENABLE function? 

1,000,00

What are cursor attributes? 

-%ROWCOUNT
-%NOTFOUND
-%FOUND
-%ISOPEN

There is a % sign in one field of a column. What will be the query to find it? 

'' Should be used before '%'.

What is ON DELETE CASCADE ? 

When ON DELETE CASCADE is specified ORACLE maintains referential integrity by automatically removing dependent foreign key values if a referenced primary or unique key value is removed.

What is the fastest way of accessing a row in a table ? 

Using ROWID.CONSTRAINTS