Answer:
A system is a collection of elements or components that are organized for a common purpose. ... A computer system consists of hardware components that have been carefully chosen so that they work well together and software components or programs that run in the computer.
Explanation:
1982 the Internet protocol was introduced as the standard network protocol on the ARPANET.
1981 access to the ARPANET was expanded.
By Pelago, INC. Founders of Pelago are: Jeff Holden<span> and </span><span>Darren Vengroff.</span>
Answer: all the answers are correct
Explanation:
Partial mesh networks is simply a packet switching networks which is connected and require that there should be establishment of a circuit before the exchange of packets.
Partial mesh networks are less expensive to implement when they're being compared to the full mesh networks and are also less redundant.
The correct statements regarding partial mesh networks are:
•the number of links connecting nodes in a partial mesh network depends upon the availability and reliability requirements of the network
• switches play an integral role in a partial mesh network, where several paths through the network are available
• redundant links and switches are used to improve the availability and reliability of partial mesh networks
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);
