Basic Concept of Multilevel Database Security - Multilevel Security for Relational Databases - page 33

2.5

2

1.5

1

0.5

0

2 3 4

Number of Classi�cation Levels

5 6

SeaView
MLR

Jajodia-Sandhu
Belief-Consistent

Smith-Winslett

Figure 2.6 The impact of varying the number of classification levels on the performance of a
multilevel database.

and union operation between horizontal, single-level relations in the
recovery algorithm.

2.6 Summary

This chapter introduced a survey of relational database security and
focused on the mandatory access control models. Then this chapter gave
a survey about relational multilevel database security management sys-
tems, explained the use of polyinstantiation in relational databases with
multilevel security, and defined how the polyinstantiation can occur
and the types of polyinstantiation. Also, this chapter presented the most
common models for multilevel secure RDBMS (relational database
management systems) and made a comparative study to explain the
strength and weakness of each model. According to this comparative
study, the MLR data model is a simple, unambiguous, and powerful
model for implementing multilevel secure RDBMS.