Database Management Systems (DBMS) were introduced to address several issues with traditional file processing systems: 1. Data redundancy and inconsistency: Traditional systems often had duplicate data in multiple places, leading to inconsistencies. 2. Data isolation: Data was scattered across varioRead more
Database Management Systems (DBMS) were introduced to address several issues with traditional file processing systems:
1. Data redundancy and inconsistency: Traditional systems often had duplicate data in multiple places, leading to inconsistencies.
2. Data isolation: Data was scattered across various files with different formats, making retrieval and management difficult.
3. Difficulty in accessing data: Retrieving data required complex programming without a standard access method.
4. Integrity problems: Ensuring data accuracy and consistency was challenging due to the need for explicit programming of constraints.
5. Atomicity issues: Ensuring operations were completed fully or not at all was difficult, risking inconsistent data states.
6. Concurrent access anomalies: Handling multiple users accessing data simultaneously often led to conflicts and inconsistencies.
7. Security problems: Traditional systems lacked comprehensive security measures for controlling unauthorized access.
8. Data independence: Changes to data structures required modifications to application programs, lacking flexibility.
DBMS solved these problems by providing centralized data management, standardized data access, built-in integrity and security measures, concurrent access control, and data independence.
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Database Security Database security has many different layers, but the key aspects are: Authentication User authentication is to make sure that the person accessing the database is who he claims to be. Authentication can be done at the operating system level or even the database level itself. Many aRead more
Database Security Database security has many different layers, but the key aspects are:
Authentication
User authentication is to make sure that the person accessing the database is who he claims to be. Authentication can be done at the operating system level or even the database level itself. Many authentication systems such as retina scanners or bio-metrics are used to make sure unauthorized people cannot access the database.
Authorization
Authorization is a privilege provided by the Database Administer. Users of the database can only view the contents they are authorized to view. The rest of the database is out of bounds to them.
The different permissions for authorizations available are:
The categories of authorization that can be given to users are:
Database Integrity
Data integrity in the database is the correctness, consistency and completeness of data. Data integrity is enforced using the following three integrity constraints:
- Entity Integrity – This is related to the concept of primary keys. All tables should have their own primary keys which should uniquely identify a row and not be NULL.
- Referential Integrity – This is related to the concept of foreign keys. A foreign key is a key of a relation that is referred in another relation.
- Domain Integrity – This means that there should be a defined domain for all the columns in a database.
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