E-R Model in DBMS vs. Relational Model in DBMS — What's the Difference?
By Tayyaba Rehman — Published on January 12, 2024
The E-R Model visualizes entities and relationships in a database; the Relational Model organizes data into tables with rows and columns.
Difference Between E-R Model in DBMS and Relational Model in DBMS
Table of Contents
ADVERTISEMENT
Key Differences
The Entity-Relationship (E-R) Model in DBMS is a conceptual design that represents the data structures and the relationships between them. The Relational Model, however, is a logical system that uses tables, also known as relations, to store data and relationships between them.
In the E-R Model, entities are defined as things that have an independent existence in the domain model. The Relational Model treats data as tuples, grouped into relations, without necessarily considering their real-world implications.
Relationships in the E-R Model are mapped out as associations between entities, which can be one-to-one, one-to-many, or many-to-many. In the Relational Model, relationships are represented by foreign keys and the natural join operation between tables.
Attributes in the E-R Model describe the properties of entities and relationships. The Relational Model uses columns in tables to define the attributes of the data it stores, with each row representing a unique record.
The E-R Model is typically used in the conceptual design phase of database development, providing a high-level view of the system. The Relational Model, being more concrete, is used to implement the actual structure of the database as it will be managed by the DBMS.
ADVERTISEMENT
Comparison Chart
Basic Unit
Entities and relationships.
Tables (relations) with rows and columns.
Representation
Conceptual diagrams.
Logical structure and schema.
Relationship Expression
Directly through lines or arrows.
Through foreign keys and joins.
Data Integrity
Defined through constraints on relationships.
Enforced by keys and referential integrity constraints.
Usage Phase
Used in the design phase.
Used in the implementation phase.
Compare with Definitions
E-R Model in DBMS
It represents real-world entities and the relationships between them.
Customer and Order were two entities related in our E-R Model.
Relational Model in DBMS
Uses primary keys to uniquely identify each row in a table.
Each customer record in our Relational Model has a unique customer ID.
E-R Model in DBMS
Focuses on the system's high-level structure.
The E-R Model provided a clear high-level view of our system's data architecture.
Relational Model in DBMS
Defines the schema that the DBMS enforces for data storage and retrieval.
The schema in the Relational Model specified how data is stored in our database.
E-R Model in DBMS
A conceptual framework that outlines the relationships between data in a database.
The team used the E-R Model to map out the database for our project.
Relational Model in DBMS
Facilitates data manipulation using operations like select, join, and project.
We used select and join operations to query the database in our Relational Model.
E-R Model in DBMS
Helps in understanding the information requirements.
The E-R Model clarified what data we needed and how it interrelated.
Relational Model in DBMS
Structures data into tables, known as relations, consisting of rows and columns.
We implemented the database design using the Relational Model.
E-R Model in DBMS
Utilizes diagrams to illustrate the database design.
Our database's E-R diagram helped identify key entities and relationships.
Relational Model in DBMS
Relies on foreign keys to establish relationships between tables.
Foreign keys helped us link Orders to Customers in our Relational Model.
Common Curiosities
How are relationships represented in the Relational Model?
Relationships in the Relational Model are represented using foreign keys and table joins.
What does the E-R Model stand for?
The E-R Model stands for Entity-Relationship Model.
Can the E-R Model exist without the Relational Model?
Yes, the E-R Model can be designed independently of the Relational Model.
Are attributes in the E-R Model the same as columns in the Relational Model?
Conceptually they are similar, with attributes in the E-R Model corresponding to columns in the Relational Model.
What is the fundamental difference between the E-R and Relational Models?
The E-R Model is a conceptual design of data relationships, while the Relational Model is a logical implementation using tables.
Is the E-R Model used for database normalization?
No, normalization is a concept applied in the Relational Model, not in the E-R Model.
How is data integrity maintained in the E-R Model?
In the E-R Model, data integrity is maintained through relationship constraints.
What is the primary advantage of the Relational Model?
The primary advantage of the Relational Model is its mathematical foundation, which allows for data independence and efficient querying.
Can I convert an E-R Model into a Relational Model?
Yes, the E-R Model can be converted into a Relational Model as part of the database design process.
Can the Relational Model handle complex relationships like the E-R Model?
Yes, the Relational Model can handle complex relationships using foreign keys and joins.
Does the Relational Model support the concept of inheritance?
Inheritance is not natively supported in the Relational Model as it is in some E-R modeling methodologies.
Are diagrams used in the Relational Model?
While not as central as in the E-R Model, schema diagrams can be used to represent the Relational Model visually.
How does the E-R Model handle many-to-many relationships?
Many-to-many relationships in the E-R Model are handled using associative entities.
What is the role of primary keys in the Relational Model?
Primary keys uniquely identify each record in a relational table.
Is SQL used in both the E-R and Relational Models?
SQL is not used in the E-R Model but is used to manipulate data in the Relational Model.
Share Your Discovery
Previous Comparison
IMAP vs. POP3
Next Comparison
Relations vs. FunctionsAuthor Spotlight
Written by
Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
