Database Management System (DBMS)
Database is collection of related data.More specifically, a database is an electronic system that allows data to be easily retrieved, manipulated and managed .
In other word: A database is a data structure that stores related and organized data. Most of databases includes multiple tables, And each tables include several different fields. Modern databases are managed using a database management system (DBMS).
What Is DBMS?
A database management system (DBMS)is defined as system software which provides a way to interact with the database, That allows a computer to retrieve, manupulate and update data.
On other hand: A database management system (DBMS) is a collection of programs that allows you to store, modify, and extract information from a database.There are the following DBMS, Which is available in the market today:
Types of DBMS:
Goals of DBMS:
The primary goal of a DBMS is to provide a way to store and retrieve database information that is both convenient and efficient
- Manage large bodies of information
- Provide convenient and efficient ways to store and access information
- Secure information against system failure or tampering
- Permit data to be shared among multiple users
Need of DBMS:
- Before the advent of DBMS, organizations typically stored information using a “File Processing Systems”.
Example of such systems is File Handling in High Level Languages like C, Basic and COBOL etc., these systems have Major disadvantages to perform the Data Manipulation. So to overcome those drawbacks now we are using the DBMS.
- Database systems are designed to manage large bodies of information.
- In addition to that the database system must ensure the safety of the information stored,despite system crashes or attempts at unauthorized access. If data are to be shared among several users, the system must avoid possible anomalous results.
Advantages and Disadvantages of Database Management Systems:
Advantages of a DBMS:
1. Control of data redundancy :
In traditional computer file processing system , each application program has its own files. In this case, the duplicated copies of the same data are created at many places. In DBMS, all the data of an organization is integrated into a single database. And avoids unnecessary duplication of data and effectively reduces the total amount of data storage required. It also eliminates the extra processing necessary to trace the required data in a large storage of data.
2. Data consistency:
By eliminating redundancy, the database approach reduces the risk of inconsistencies occurring in data files. It ensure that these multiple copies arr consistent.
3. Data Sharing:
In DBMS, data can be shared by authorized users to the organization. The DBA(Data Base Administator) manages the all data and gives the rights to users to access the data. Most of users can be authorized to access the same set of data simultaneously. Similarly, the data of same database can be shared between different application programs.
4. Data Integrity:
In DBMS, data in database is stored in tables. A single database contains many tables and relationships can be created between tables. This is very easy to retrieve and update data.
5. Data Atomicity:
DBMS ensure either the transaction is fully complete or it is rolled back to the previous committed state. It does not allow the system to be in a partially committed state. In our example above, DBMS commits marks change transaction before calculating the total. If there is any crash or shutdown of the system, before committing the marks, then updated marks will be rolled back to the original marks. Hence it makes sure atomicity of the transaction is achieved.
6. Data Independence:
Data Independence is usually includes two type of view, Which are followings:
- Physical Data Independence.
- Logical Data Independence.
1.Physical Data Independence:
Physical data independence allows changes in the physical storage devices without changes in the conceptual view or any of the external views. Thus, the files may migrate from one type of physical media to another or the file structure may change without any need for changes in the application program.
2. Logical Data Independence.
Logical data independence ensure that the conceptual schema can be changed without affecting the existing external schemas.
Disadvantages of a DBMS:
A significant disadvantage of the DBMS system is cost,And the cost of DBMS varies significantly, depending on the environment and functionality provided. Also need a processor with high speed of data processing and large amount of memory. It also needs large memory to run efficiently. It means that you have to up grade the hardware used for file-based system. Similarly, DBMS software is also very costly.
In many organization, all data is integrated into a single database. If database is damaged due to any of reason like electric failure or database is corrupted on the storage media, then your valuable data may be lost forever.
DBMS provide the multiple functionality to give the user the best.the underlying behaviour of the software has become a bit complex.he designers and developers should have thorough knowledge about the software to get the most out of it.
4)Cost of Trainings:
Most of the database management system are often complex so the training is required for users to use the DBMS. Such as database administrator, application programmers, data entry operations etc. are required to handle the DBMS. So organization has to pay a good salaries to these persons. Thus, the system cost increases.
Difference between File system & DBMS:
|File system is a collection of data. Any management with the file system, user has to write the procedures.||DBMS is a collection of data and user is not with the file system, user has to write the procedures required to write the procedures for managing the database.|
|File system gives the details of the data.||DBMS provides an abstract view of data that hides representation and Storage of data. the details.|
|In File system storing and retrieving of data cannot be done efficiently.||DBMS is efficient to use since there are wide be done efficiently.varieties of sophisticated techniques to store and retrieve the data.|
|Concurrent access to the data in the file system has deleting some information, updating some information||DBMS takes care of Concurrent access using some many problems like : Reading the file while other form of locking.|
|Protecting a file under file system is very difficult.||DBMS has a good protection mechanism.|