When you use this option to create a view with a where
condition, the system wont allow to perform any action which
will invalidate the definition of the view.

ex:
create view test
as 
select firstname,lastname from Employees where sal<10000
with Check option

If this returns 10 rows when you are updating the view if
any action is being done which updates the sal so that the
view returns lesser number of records is not allowed.

The CHECKPOINT statement saves time in a subsequent 
recovery by creating a point at which all modifications to 
data and log pages are guaranteed to have been written to 
disk.

Checkpoints also occur: 

When a database option is changed with ALTER DATABASE. A 
checkpoint is executed in the database in which the option 
is changed.


When a server is stopped, a checkpoint is executed in each 
database on the server. These methods of stopping Microsoft 
SQL Server 2000 checkpoint each database