Database and Advantages of using DBMS approach
Database is a collection of related data.By data mean known fact that can be recorded and that have implicit meaning.This collection of related data with an implicit meaning is a database.
A database management system is a collection of programs that enables users to create and maintain a database.The DBMS is a general purpose software system.
That software system defining,manipulating,constructing,sharing database among various users and application.
Advantages of using the DBMS approach
- Controlling Redundancy.
- Restricting Unauthorized Access.
- Providing Backup and Recovery.
- Providing Multiple user interface.
- Enforcing Integrity Constraints.
- Representing complex relationships among Data.
- Providing persistent storage for program objects.
- Providing storage structures an search techniques for query processing.
Controlling Redundancy
In database approach the views of different user groups are integrated during database design.Database design that stores each logical data item in only one place in the database.This is known as data normalization and it ensure consistency and save storage space.Controlled redundancy improve the performance of queries.
Restricting unauthorized Access
When multiple users share a large database it is likely that most users will not be authorized to access all information in the database.Some users may only be permitted to retrieve data whereas others are allowed to retrieve and update.A DBMS should provide a security and authorization subsystem which the DBA uses to create accounts and specify accounts restrictions.
Providing Backup and Recovery
A DBMS must provide facilities for recovering from hardware or software failures.The backup and recovery subsystem of the DBMS is responsible for recovery.
Providing Multiple user Interface
Because many types of users with varying levels of technical knowledge use a database.A DBMS should provide a variety of user interfaces.These include query languages for casual users,programming language interface for application programmers,menu driven interfaces and natural language interfaces for standalone users.
Enforcing Integrity Constraints
Most database application have certain integrity constraints that must hold for the data.A DBMS should provide capabilities for defining and enforcing these constraints.(Uniqueness constraints,referential integrity constraints.).
Representing Complex Relationship among Data
A database may include varieties of data that are interrelated in many ways.A DBMS must have the capability to represent a variety of complex relationships among the data to define new relationship as they arise and to retrieve and update related data easily and efficiently.
Providing persistent storage for program object
Database can be used to provide persistent storage for program objects and data structures.Programming languages have complex data structures such as record types in c++ or java.The values of program variables or objects are discarded once a program terminates unless the programmer explicitly stores them in permanent files.Hence a complex object in C++ can be stored permanently in object oriented DBMS.Such as object is said to be persistent since it survives the termination of program execution and can later be directly retrieved by another C++ program.
Providing Storage Structures and Search Techniques for efficient Query Processing.
Database typically stored on disk the DBMS must provide specialized data structures and search techniques to speed up disk search for the desired records.Auxiliary files called indexes are used for this purpose.In order to process the database records needed by a particular query those record must be copied from disk to main memory.Therefore DBMS often has a caching module that maintains parts of the database in main memory buffers.
The query processing and optimization module of the DBMS is responsible for choosing an efficient query execution plan for each query based on the existing storage structures.
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