Databases Reference
In-Depth Information
CHAPTER
7
LEARNING OBJECTIVES
Objectives
Introduce the functions, or services, provided by a DBMS
●
Describe how a DBMS handles updating and retrieving data
●
Examine the catalog feature of a DBMS
●
Illustrate the concurrent update problem and describe how a DBMS handles this problem
●
Explain the data recovery process in a database environment
●
Describe the security services provided by a DBMS
●
Examine the data integrity features provided by a DBMS
●
Discuss the extent to which a DBMS achieves data independence
●
Define and describe data replication
●
Present the utility services provided by a DBMS
●
INTRODUCTION
In Chapter 6, you learned the steps that the database designer completed to design the Premiere Products database.
Management next asks the database administrator (DBA) to explain the functions that a DBMS performs in managing a
database. The DBA describes nine functions performed by a DBMS; this chapter explains these nine functions. Some of the
functions have been introduced in previous chapters; however, they are re-emphasized here because they are key processing
components of a DBMS. The nine functions of a DBMS are:
Update and retrieve data.
A DBMS must provide users with the ability to update and retrieve data in a database.
●
Provide catalog services.
A DBMS must store data about the data in a database and make this data accessible to users.
●
Support concurrent update.
A DBMS must ensure that the database is updated correctly when multiple users update
●
the database at the same time.
Recover data.
A DBMS must provide methods to recover a database in the event the database is damaged in any way.
●
Provide security services.
A DBMS must provide ways to ensure that only authorized users can access the database.
●
Provide data integrity features.
A DBMS must follow rules so that it updates data accurately and consistently.
●
