DBMS FUNCTIONS, ADVANTAGES AND DISADVANTAGES

 

DBMS FUNCTIONS

DATA DEFINITION

The DBMS must be able to accept data definitions(external, internal and conceptual schemas, and all associated mappings) in source form and convert to the appropriate object form.

 DATA MANIPULATION

The DBMS must be able to handle request from the user to retrieve and possibly update existing data in the database, or to add a new data to the database.

DATA SECURITY AND INTEGRITY 

The DBMS must be able to monitor user requests and reject any attempts to violate the security and integrity checks defined by the database administrator.

  DATA RECOVERY AND CONCURRENCY  

The DBMS must have the capability of recover from, or minimize the effects of a system crash. 

 DATA DICTIONARY 

The DBMS must provide a system database called the database dictionary.

ADVANTAGES OF DBMS

 REDUCED DATA REDUNDANCY 

In database system, data redundancy is avoided by keeping a single copy of the data.

 DATA INTEGRITY

 Since a single copy of a particular data is stored in the database, you can be certain that the changes to the data will be reflected in all future uses of that data.

  DATA INDEPENDENCE

 The structure of the database system requires that data be independent of other data in the database and the software used to access the database.

 DATA SECURITY

 A database system can have additional security measures as part of the database software product.

 DATA CONSISTENCY 

Data consistency is maintained in the database environment.

EASIER USE OF DATA 

Data is easier to use in the database environment.

 LESS STORAGE 

Since data redundancy is reduce if not eliminated, the database will occupy less storage space.

DISADVANTAGES OF DBMS

 COMPLEXITY

 Databases and their associated DBMS are extremely complex.

EXPENSE

 The installation of the DBMS and its databases onto the current system requires careful planning because of the possibility of the need for additional hardware. 

VULNERABILITY 

Because data in a database is in a central location, it is vulnerable to partial or complete destruction when a breakdown of hardware components occur or in software mistake.

 SIZE

 A typical mainframe database is very large.

 TRAINING COSTS 

When a company purchase a database product, it must first train one or more individuals to be the database administrator for the new product.

 COMPATIBILITY 

One of the pitfalls of most database systems is their incompatibility with other database systems.

 LOCKING-IN OF TECHNOLOGY 

What if the vendor expresses a desire to abandon the product? There is a possibility that they will have to redesign their system from scratch.