Computer Science – 8.2 Database Management Systems (DBMS) | e-Consult
8.2 Database Management Systems (DBMS) (1 questions)
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Hierarchical and Network Models: These were early database models that were prevalent before the relational model gained popularity. They organize data in a tree-like (hierarchical) or graph-like (network) structure.
Hierarchical Model:
- Advantages: Simple to understand and implement. Efficient for representing one-to-many relationships (e.g., a company has many employees).
- Disadvantages: Inflexible; difficult to represent many-to-many relationships. Data redundancy can be an issue. Modifying the structure can be complex.
Network Model:
- Advantages: More flexible than the hierarchical model; can represent many-to-many relationships.
- Disadvantages: Complex to design and implement. Difficult to navigate and maintain. Data redundancy can still be a problem.
Comparison with the Relational Model:
The relational model differs significantly from the hierarchical and network models in the following ways:
- Flexibility: The relational model is much more flexible than the hierarchical and network models. It allows for complex queries and data manipulation.
- Data Redundancy: The relational model minimizes data redundancy through normalization. The hierarchical and network models often have significant data redundancy.
- Ease of Use: The relational model uses SQL, a standardized query language, which is easier to learn and use than the navigation languages used in hierarchical and network models.
- Data Independence: The relational model provides better data independence, meaning that changes to the database structure have less impact on applications.
In summary, while hierarchical and network models were important steps in database development, the relational model's flexibility, data integrity features, and ease of use have made it the dominant model in modern DBMSs.