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Dbms database models
This document discusses different database models including hierarchical, network, entity-relationship, and relational models. The hierarchical model organizes data in a tree-like structure with parent-child relationships. The network model extends the hierarchical model by allowing nodes to have more than one parent. The entity-relationship model divides data into entities and attributes and represents relationships visually. The relational model, introduced by E.F. Codd in 1970, organizes data into two-dimensional tables related through common fields and is the most widely used database model today.
Dbms database models
- 1. DBMS DATABASE MODELS Presentedby:- Surender Sanjeev Harsh manish Presented to:- Arbind sharma
- 2. DATABASE MODELS ADatabase model defines the logical design and structure of a database and defines how data will be stored, accessed and updated in a database management system.
- 3. TYPES OF DATABASEMODELS:- Hierarchical Model Network Model Entity-relationship Model Relational Model
- 4. HIERARCHICAL MODEL Thisdatabase model organizes data into a tree- like-structure, with a single root, to which all the other data is linked. The hierarchy starts from the Root data, and expands like a tree, adding child nodes to the parent nodes.
- 5. In hierarchicalmodel, data is organized into tree-like structure with one one-to-many relationship between two different types of data, for example, one department can have many courses, many professors and of-course many students.
- 6. NETWORK MODEL Thisis an extension of the Hierarchical model. In this model data is organized more like a graph, and are allowed to have more than one parent node.
- 7. In thisdatabase model data is more related as more relationships are established in this database model. Also, as the data is more related, hence accessing the data is also easier and fast. This database model was used to map many-to-many data relationships.
- 8. ENTITY-RELATIONSHIP MODEL Inthis database model, relationships are created by dividing object of interest into entity and its characteristics into attributes.
- 9. E-R Modelsare defined to represent the relationships into pictorial form to make it easier for different stakeholders to understand. This model is good to design a database, which can then be turned into tables in relational model
- 10. RELATIONAL MODEL Inthis model, data is organized in two- dimensional tables and the relationship is maintained by storing a common field. This model was introduced by E.F Codd in 1970, and since then it has been the most widely used database model, infact, we can say the only database model used around the world.
- 11. The basicstructure of data in the relational model is tables. All the information related to a particular type is stored in rows of that table. Hence, tables are also known as relations in relational model.
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