Data model
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This document presents an overview of data models. It defines a data model as how the logical structure of a database is modeled, introducing abstraction in a DBMS. Several types of data models are described, including hierarchical, network, relational, entity-relationship, object-oriented, document, entity-attribute-value, star schema, and object-relational models. The entity-relationship model is explained in more detail, noting that it is based on entities, attributes, and relationships between entities. Entities represent real-world objects and are described by attributes, while relationships define associations between entities.
Data model
- 1. Data Model Presentation By:- Sumit Rana BCA (2015-18)
- 2. A Three-dimensional Representation Of A Person Or Thing Or Of A Proposed Structure, Typically On A Smaller Scale Than The Original. What is a Model ?
- 3. What is Data Model? • Data models define how the logical structure of a database is modeled. • Data Models are fundamental entities to introduce abstraction in a DBMS. • Data models define how data is connected to each other and how they are processed and stored inside the system.
- 4. Types of Data Models • Hierarchical Model • Network Model • Relational Model • Entity-relationship model • Object-oriented database model • Document model • Entity-attribute-value model • Star schema • The object-relational model, which combines the two that make up its name
- 5. Hierarchical Model • In this model each entity has only one parent but can have several children . At the top of hierarchy there is only one entity which is called Root.
- 6. Network Model • In the network model, entities are organized in a graph, in which some entities can be accessed through several path
- 7. Relational Model • In this model, data is organized in two-dimesional tables called relations. The tables or relation are related to each other. • The most common model, the relational model sorts data into tables, also known as relations, each of which consists of columns and rows.
- 8. Entity-Relationship Model • Entity-Relationship (ER) Model is based on the idea of real-world entities and relationships among them. While preparing real- world scenario into the database model, the ER Model creates entity set, relationship set, general attributes and constraints.
- 9. ER Model is based on − •Entities •Attributes •Relationships
- 10. Entities • An entity can be a real-world object, that can be easily identifiable. • For example, in a school database, students, teachers, classes, and courses offered can be considered as entities. All these entities have some attributes or properties that give them their identity.
- 11. Attributes • Entities are represented by means of their properties, called attributes. All attributes have values. • For example, a student entity may have name, class, and age as attributes.
- 12. Relationships • The association among entities is called a relationship. • For example, an employee works_at a department, a student enrolls in a course. Here, Works_at and Enrolls are called relationships.
- 13. Sources • www.lucidchart.com • www.tutorialspoint.com • www.studytonight.com
- 14. Any Questions? In Any Thing I Explained
- 15. Thanks You Presentation By:- Sumit Rana BCA (2015-18)