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:
SQL injection is a form of hacking that uses user input fields.
Explanation:
SQL injection is when a piece of code or entire algorithm is input where a program prompts for user input. They can be used to change or access data. To prevent this, a programmer should scrub inputs. Scrubbing data removes slashes and arrows, which or commonly used in code.
Answer:
Specialized fr just want point lol
Explanation:
Explanation:
We can divide the multiplex in different categorize, for example:
- FREQUENCY DIVISION MULTIPLEXERS (FDM)
-
TIME DIVISION MULTIPLEXERS (TDM)
-
STATISTICAL TIME DIVISION MULTIPLEXERS (STDM).
But in this case, we're going to explain about the time and frequency, because the time division multiplex differ to frequency, because the circuit is divided horizontally, and the time is vertically
b. splits the communication circuit vertically (with time slots) instead of horizontally
Answer:
The answer is "Option A".
Explanation:
The dynamic search ads also known as interactive contextual ads, that utilizes google advanced website browsing technologies to dynamically address relevant results requests based on the quality of a chain's website. These ads are beneficial for strategies, and other choices were wrong which can be described as follows:
- In option B, It helps to upload all the dynamic search ads URLs quickly.
- In option C, It helps to control computer service.
- In option D, It increases the network traffic.
