Characteristics of the Database Approach

Characteristics of the Database Approach


Self-Describing Nature of a Database System
Insulation between Programs and Data, and Data Abstraction
Support of Multiple Views of the Data
Sharing of Data and Multiuser Transaction Processing

Self-Describing Nature of a Database System


A complete definition or description of the database structure and constraints
DBMS software works equally well with any number of database applications
DBMS catalog stores the description of the database. The description is called meta-data


Insulation between Programs and Data, and Data Abstraction
Program-data independence
Allows changing data storage structures and operations without having to change the DBMS access

programs
Program - operation independence :-
The interface (or signature) of an operation includes the operation name and the data types of its

arguments (or parameters).
The implementation (or method) of the operation is specified separately and can be changed without affecting the interface.
Data Abstraction
A data model is used to hide storage details and present the users with a conceptual view of the database

Support of Multiple Views of the Data


A database typically has many users, each of whom may require a different perspective or view of the database.
A view may be a subset of the database or it may contain virtual data that is derived from the database files but is not explicitly stored
A multiuser DBMS whose users have a variety of applications must provide facilities for defining multiple views

Sharing of Data and Multiuser Transaction Processing

Allow multiple users to access the database at the same time
Concurrency control
Allowing a set of concurrent users to retrieve and to update the database.
Concurrency control within the DBMS guarantees that each transaction is correctly executed or completely aborted.
OLTP (Online Transaction Processing) is a major part of database applications.