Chapter 2

1. is a matrix consisting of a series of row/column intersections.
4. level operates at the lowest level of abstraction, describing the way data are saved on storage media such as disks or tapes.
7. depicts a set of one-to-many (1:M) relationship between a parent and its children segments. (Each parent can have many children,but each child has only one parent.)
9. is a restriction placed on the data.
10. is a characteristic of an entity.

2. is database desigh tool. It is easier to examine structures graphically than to describe them in text,database designers prefer to use a graphical tool in which entities and their relationships are pictured.
3. describes and association among entities.
5. is the end user's view of the data environment.
6. is a brief,precise, and unambiguous description of a policy, procedure, or principle within a specific organization.
8. an employee may learn many job skills, and each job skill may be learned by many employess.