Concept of Dbms

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Angeles University Foundation

College of Computer Studies

Bachelor of Science in Information Technology

DMS 410 – Database Management System 1

Chapter 1 - Introduction to Database Management
Answers to Review Questions

What is redundancy? What problems are associated with redundancy?

1. Redundancy is the duplication of data or the storing of the same data in more than one place. Redundancy wastes space, makes the updating of data more cumbersome and time-consuming, and can lead to inconsistencies.

Besides redundancy, what other problems are associated with the non-database approach to processing data?

2. The problems, other than redundancy, associated with the nondatabase approach to processing data include difficulties accessing related data, limited security features to protect data from access by unauthorized users, limited ability for multiple users to update the same data at the same time, and size limitations.

What is an entity? An attribute?

3. An entity is a person, place, object, event, or idea for which you want to store and process data. An attribute, which is also called a field or column in many database systems, is a characteristic or property of an entity.

What is a relationship? A one-to-many relationship?

4. A relationship is an association between entities. A one-to-many relationship exists between two entities when each row in the first entity matches many rows in the second entity and each row in the second entity matches only one row in the first entity.

What is a database?

5. A database is a structure that can store information about multiple types of entities, the attributes of those entities, and the relationships among the entities.

How do you create a one-to-many relationship in a database system?

6. In a database system, you create a one-to-many relationship by using common columns in the two tables.

What is an E-R diagram?

7. An E-R diagram represents a database in a visual way by using a rectangle for each entity, using a line to connect two entities that have a relationship, and placing a dot at the end of a line to indicate the “many” part of a one-to-many relationship.

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What is a DBMS?

8. A database management system (DBMS) is a program, or a collection of programs, through which users interact with a database.

What is a database design?

9. Database design is the process of determining the table structure of the desired database.

What is a form?

10. A form is a screen object used to maintain, view, and print data from a database.

How is it possible to get more information from the same amount of data by using a database approach as opposed to a non-database approach?

11. It is possible to get more information from the same amount of data by using a database approach as opposed to a nondatabase approach because all data is stored in a single database, instead of being stored in dozens of separate files, making the process of obtaining information quicker, easier, and even possible in certain situations.

What is meant by the sharing of data?

12. Sharing of data means that several users can have access to the same piece of data and use it in a variety of ways.

What is a DBA? What kinds of responsibilities does a DBA have in a database environment?

13. The DBA (database administrator or database administration) is the central person or group in an organization in charge of the database and the DBMS that runs the database. The DBA attempts to balance the needs of individuals and the overall needs of the organization.

How does consistency result from controlling redundancy?

14. Multiple copies of the same data in an organization leads to inconsistency because each piece of data can have different values. Controlling redundancy is the result of eliminating, or at least reducing, the multiple copies. Improved consistency is the result of this controlled...
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