Answer:
Explanation:
Multinational Companies tend to have millions of users from all over the globe who use their services and in doing so provide their information. This information gets saved on the databases of these companies. It is then up to the company on how they will use this information. This is where ethicality comes into play. A company can act ethically and protect the information that has been entrusted to them by their user, or they can act unethically and use the users' personal data to make profits. It has recently come to light that some companies have been using users' private data and would sell it to other companies for profit. These buying companies would then use the data for a variety of things such as ad targeting and statistics. These companies profited massively and the actual owners of the data did not, which makes this incredibly unethical.
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);
The correct answer or solution to the question above is marked A
