A composite primary key<span> is a set of several primary </span>keys<span> that, together, uniquely identifies each record.</span>
Primary keys are used as identifiers of composite entities. In this case each primary key combination is allowed only once in the *:* relationship.
Other case where primary keys are used is as identifiers of weak entities, where the weak entity has a strong identifying relationship with the parent entity.
Answer:
Contrast is a tool that photographers use to direct viewers' attention to their subject. There are two types: Tonal Contrast and Color Contrast. TC refers to the difference in tones from the lightest tone to the darkest tone, in other words, the difference in tones from white to gray to black.
Explanation:
heheh there you go
Answer: The statement implies that the hackers psychologically manipulate the human to access the information they need.
Explanation: The author states that the hacker does not only exploits technology to get system access or to gather information. But there is another pivotal part of hacking. He refers to this part as "social engineering".
Social engineering from information security perspective means manipulate human emotions and convincing them to disclose some confidential information. Hacker often hacks or defrauds after gaining confidence and trust of a person.
Phishing is an example. It is a fraudulent technique for getting some secret information. Phisher sends an email pretending to be from some reputable organization to persuade people to divulge private information like passwords and credit card numbers, ATM card pin etc.
