A collection of data designed to be used by different programmers is called DATABASE. We will define it as a collection of interrelated data stored together with controlled redundancy to serve one or more applications in an optimal manner; The data is stored so that it is independent of the programs that use the data; A common, controlled approach is used to add new data and modify and retrieve existing data within the database. It is said that a system contains a collection of databases if each one of them is completely separated in its structure. The database has many applications in the client server model. In order to increase the speed of data recovery we use the distributed database technique. The distributed database has expanded due to the growing requirement in database management systems. To increase the response times of the systems, the distributed database is used. The distributed database is the best method to handle the data in the network and reduces the load on the single server. A central control will be present to organise the distributed data. In this article we will see how data is distributed across the network and how it is used when required.
Uses DBMS
Data independence and efficient access
Data integrity and security
Uniform data management
Concurrent access, accident recovery
Purpose of the DBMS
Redundancy and inconsistency of data
Difficulty in the new program to carry out each new task
Data isolation
Integrity issues
Security issues
Data Models
There are three types of models.
Hierarchical model
Network model
Relational Model
Architecture
External level
Conceptual level
Internal level
DBMS Components
Hardware
Software
Data
People
Procedure
Advantages of DBMS
Control of redundancy
Sharing of data
Consistency of data
Data integration
Integration constraints
Data security
Report Writers
Disadvantage of DBMS
Cost of hardware and software
Cost of data conversion
Cost of staff training
Designation of technical personnel
Damage to the database