Database Reference
In-Depth Information
6. Functional dependency is a relationship between two attributes such that the value of one
attribute determines the value in the other. (T/F)
7. Integrity constraint is a data integrity rule (T/F)
8. join dependency is not a cyclical relationship between three relations (T/F)
Long answer type questions
1. What normalization is, its benefits and potential hazards
2. What do you mean by Non-loss Decomposition? Explain with an example.
3. What is functional dependency?
4. What is the difference Transitive dependence and Multiple valued dependency?
5. Explain term anomalies and it types.
6. Explain different types of normalization.
7. Explain process of normalization.
Chapter 6
DATABASE ACCESS AND SECURITY
6.1 Database security
Security has become an essential consideration in modern systems. The foundation of any
security system is user authorization and authentication. This is the process by which a
user is validated to ensure that he is allowed to perform the operation on database. Some
DBMSs integrate with operating system security for this, others maintain their own user
and password lists, and still others integrate with external directory services servers. Enfor-
cing security restrictions and implementing a security scheme are the responsibility of the
DBMS software. Each time the DBMS retrieves, inserts, deletes, or updates data, it does
so on behalf of some user. The DBMS permits or prohibits the action depending on which
user is making the request. Security is usually applied to tables and views, but other ob-
jects such as forms, application programs, and entire databases can also be protected. Most
users will have permission to use certain database objects but will be prohibited from using
others. Privileges are the actions that a user is permitted to carry out for a given database
object
6.1.1 Why Is Security Necessary?
Here are some reasons why security must be designed into your computer systems:
Databases access through the Internet, or through any network, are vulnerable to hackers
and other criminals those can damage or steal the data.
