The Integrity of Database System

The integrity of the system refers to the correctness and uniformity of that particular system. The integrity of database system refers to the correctness and constancy of that particular data placed in the database.

The integrity check is categorized into two modes

• Implicit check mode
• Explicit check mode

Implicit checks are those which allow domain, tabular and referential constraints same as they applied in the rules of the relational model. Explicit checks are those, which enforces to apply the rules of the administration and management control provided by the DDBMS. As specified explicit checks are one of the two key elements (along with views) of certificate endorsement of the relational database architectures.

According to Bell and Grisom [BellGris92], security of data integrity is quite difficult in a heterogeneous distributed environment as compared to homogeneous one. The extent of main central control states the level of complexity to manage the integrity constraints. High main central control is inversely proportional to hard to manage the integrity checks. In homogenous distributed environment has very strong central control because the DBMS schemas of each database site are same. However, the integrity checks are easily satisfied in the homogenous environment. While on the other hand in heterogeneous distributed network the DBMS schemas of multiple organizations on some site are dissimilar, so in heterogeneous environment, many problems will arise that threaten the integrity of distributed data.

There is a list of 3 problems that arise due to heterogeneous behavior:

• Contradiction among local integrity checks
• Hard to defining global integrity checks
• Contradiction among local and global checks

Local integrity checks are easy to implement in a distributed environment because it is confined to respective site organization. While on the other hand global integrity checks are separated from the respective organizations. It was taken into account as a whole database. It may not ever be applicable to alter the structure of whole organization just to configure the distributed environment conformably.

Bell and Grisom explain that local integrity checks relatively differ in the heterogeneous distributed database. The differences check from the differences in the respective organizations. This contradiction can lead to the problems, peculiarly with particular composite queries that depend on data that reside on multiple sites in the database. The strategy adopted to accomplish global integrity checks can reduce the inconsistency between individual databases. But it is not as simple to implement as simple to say .while alternatively global integrity checks are placed estranged from the individual organizations. An accomplishment of the distributed environment by changing the architectural model of individual site databases is the very impractical way.

Eventually, it will result in a contradiction between local and global checks. The level of central control is related to the Inconsistencies present. If there is strong global control, the global integrity check will take primacy. If central control is not sufficiently strong, local integrity checks will be prior.