Characteristics of the Database Approach
1. Manages Information
A database manages all the information in their required fields (according to column definition and ids).
2. Easy Operation Implementation
All the operations like insert, delete, update, search, etc. by SQL queries. It is a flexible and easy way. For this user required information of column name and appropriate value. Queries make it more powerful.
3. Multiple Views of Database
A view is a subset of the database or interface. It is defined according to user requirements. Different users of the system may have different views of the same system.
Every view contains only the data of interest to a user or a group of users.
4. Data for Specific Purpose
A database is designed for a specific purpose according to the group of user and application interests.
For example, a database of the student management systems is designed to maintain the record of students’ marks, fees, and attendance, etc. This data has the specific purpose of maintaining student records.
For example, the library system has three types of users, 1. official administration of the college, 2. librarian, and 3. students.
5. Represent Real World Applications
A database represents real-world applications. If any change in the real world then it is reflected in the database. Example: - railway reservation system - Maintaining records of passengers, waiting list, train arrival and departure time, certain day, etc. related to each train.
6. Logical Relationship Between Records and Data
A database maintains a logical relationship between records and data. So a user can access various records according to various logical conditions by a single query from the database.
7. Insulation Between Program and Data
In the database approach, the data structure is stored in the system catalog, not in the programs. If we want to change the structure of a file then no need to change the program. This feature is called program-data independence.
It is not found in the file-based system.
8. Self-describing nature of a database system
A database system is referred to as self-describing by metadata. Metadata defines and describes the data and relationships between tables in the database.
This information is used by the DBMS software or database users if needed.
This type of nature is not found in file-based systems.
9. Sharing of data and multiuser system
Current database systems can access by multiple users at the same time. This feature is called concurrency control strategies. These strategies ensure that the data accessed are always correct and integrated.
10. Control of data redundancy
In the database approach, each data item is stored in only one place in the database. So single data does not repeat more than one time. This feature improves system performance.
Redundancy is controlled by application programming and minimized when designing the database.
11. Enforcement of integrity constraints
database approach provides the ability to define and enforce certain constraints to ensure that users enter valid information and maintain data integrity.
A database constraint is a restriction or rule that dictates what can be entered or edited in a table such as a postal code using a certain format or adding a valid city in the City field.
12. Restriction of unauthorized access
A database approach should provide security to create and control different types of user accounts and restrict unauthorized access.
It provides privileges to access or use data from a database these are read-only access (i.e., the ability to read a file but not make changes), and read and write privileges, (both read and modify a file).
13. Transaction processing
A database approach supports a concurrency control subsystem that ensures that data remains consistent and valid during transaction processing even if several users update the same information.
14. Backup and recovery facilities
Backup and recovery are methods that are used to protect your data from loss. Backup means storing database copy to another drive or place. If a hard drive fails or is not accessible then it recovers the database from backup places.
If a computer system fails in a complex update process, the recovery method is accessed and restored to its original state.
============================================
Advantages
A number of advantages of DBMS. These are:
1. Controlling data redundancy.
Redundancy means storing the same type of data on the different parts DBA avoids unnecessary duplication of data and reduces the storage space.
Redundancy leads to several problems:- duplication of efforts, storage space waste, and inconsistent data.
2. Minimise data inconsistency
Inconsistency means different versions of the same data appear in different places.
data consistency is obtained if a data item appears only once. Any update to its value has to be performed only once.
3. Restricting unauthorized access
Data is stored centrally so enforcing forcibly Security constraints is easier.
The system does not provide to accessing same privileges to all users.
Provides a security subsystem to create and control the user accounts such as user ID and password.
Different checks can be established for each type of access as addition modification deletion
To each piece of information in the database.
4. Improve data access
DBMS provides quick answers to queries for data manipulation.
5. Support multiple views of data
A view is a subset of a database that contains virtual data derived from the database file but it does not exist in physical form.
Accessed by any user and have different viewpoints for use of data.
Users may not need to be aware of how and where the data they refer to is stored.
6. Enforcing integrity constraint
Various integrity constraints are identified by database design during database design.
these data integrity constraints can be and forced automatically by the DBMS and others may have to be checked by the application programs.
7. Providing backup and recovery
Recovering from hardware and software failure such as power failure, software error.
saving the data to some other machine periodically is known as backup data.
DBMS recover subsystem either revert back up revert back the database to the state which exists prior to the start of a transaction or resume the transaction from the point it was interesting so that it's completely a fact can be recorded in the database
8. Integration of data
Data in the database is stored in the table.
A single database contains multiple tables and the relationship can be created between the tables.
It makes it easy to retrieve and update data.
9. Concurrent access and crash recovery
Data is accessed by only one user at a time.
DBMS protects users from the effects of some system failures
Concurrency control software to ensure that several users are trying to update the same data at the same time.
It should be maintained in a controlled manner
10. Reduced application development time
Develop the application program according to the user's needs.
Other issues like concurrent access security data integrity etc. are handled by the DBMS itself so application development time is reduced.
11. Better service to the user
It improves service data can be shared and the techniques easier to respond to expected information requests.
12. Standard can be enforced
Standards are easier to enforce.
It may be related to the naming of data, the format of data, the structure of data, etc.
It is usually desirable for the purpose of data interchange for migration between systems.
13. Data model must be developed
Building an overall view of an organization’s data is usually cost-effective in the long term.
14. Data sharing
Data is shared among multiple users or application programs.
New applications can be developed to use the same store data.
Satisfy the data requirements of a new application without having to create any additional data or with minimal modification.
15. Data independence.
The system data descriptions are separated from the application programs so if any changes in the data structure are not reflected in the application program.
16. Transaction processing.
The DBMS includes a concurrency control subsystem to ensure that several users trying to update the same data do so in a controlled manner so that the result of the update is correct.
17. Providing data security.
Unauthorized persons must not access such confidential data.
The DBA (Database Administrator) is the controller of the database.
He ensures that the proper access procedures are followed.
Performs some checks before permitting access to sensitive data,
Different levels of security according to the significance of various types of data.
For example, a manager in the company can access only the salary structure of employees in his/her department but cannot access the medical history of any employee.
Disadvantage of DBMS
1.
Cost of hardware and
software
A processor with the
highest speed of data processing and memory of large size is required to
run the DBMS software.
DBMS software is also
very costly.
2. Cost of data conversion
For this, we have to higher a database and
database designer to convert data from one format to another format.
A lot of money and
developing software’s are required
3. Cost of staff training
Complex systems required
training for users.
Training is required at
all levels including programming application development, database
administration, and database design. For this
lot of amount for the training of staff is required
4. Appointing technical staff
Train technical person
such as database administrator, application programmer, database designer, and data
entry operators are required to handle the DBMS software of organization and
these salaries are very high.
5. Database damage
All
data is integrated into a single database.
If the database is damaged due to electronic failures or the database is corrupt on the
storage media then our valuable data may be lost forever.
6. Privacy and security is reduced
In a database information
is stored centrally but it is available to the remote users then it is possible
to the destruction of data.
So, required technical
administrative, and legal measures.
==============================================================
0 Comments