For the view of Exercise 4.18, explain why the database system would not allow a tuple to be inserted into the database through this view.
For reference
For the database of Figure 4.12, write a query to find the ID of each employee with no manager. Note that an employee may simply have no manager listed or may have a null manager. Write your query using an outer join and then write it again using no outer join at all.
OUTER JOIN
select e.ID from employee e left outer join manages m on e.ID = m.ID
where m.manager_id is null;
NO OUTER
select e.ID from employee e where e.ID not in (select m.ID from manages m) or e.ID in (select m.ID from manages m where m.manager_id is null);
Answer:
freeware
Explanation:
a freeware is a software that is available free of charge but is not distributed with the source code.
RDO.
RDO uses the lower-level DAO and ODBC for direct access to databases.
Answer:
two million years ago
Thomas Edison, American inventor who, singly or jointly, held a world-record 1,093 patents. In addition, he created the world's first industrial research laboratory.
Answer:
B. DDI
Explanation:
A(n) DDI event is an alert that is produce or invoke when the gossip traffic allow a platform to conclude that an attack or potential attack is under way.
A device driver is a computer program that operates or controls a particular type of device that is attached to a computer system.
A driver provides or supply a software interface to hardware devices which enable the operating systems and other computer programs to access hardware functions without needing to know the exact details in respect of the hardware being used.
DDI means Device Driver Interface
A driver relate or communicate with the device via the computer bus or communications subsystem to which the hardware is connected. Whenever a calling program invokes a routine in the driver, the driver will subsequently transmit commands to the device.
