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# Data models

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### Data models

1. 1. Mrs. Maninder Kaur professormaninder@gmail.comManinder Kaur www.eazynotes.com 1
2. 2. MODELA Model is representation of reality, ’real world’ objects and events and their associations.A database model is an organizing principle that specifies particular mechanism of data storage and retrieval.The model explains, in terms of services available to an interfacing application, how to access a data element when other related elements are known. Maninder Kaur www.eazynotes.com 2
3. 3. Components of Data ModelsStructure Part: Consisting of set of rules according to which databases can be constructed.Manipulative Part: Define the types of operation that are allowed on the data.Set of Integrity Rules: Which ensures that data is accurate. Maninder Kaur www.eazynotes.com 3
4. 4. Purpose of Data ModelTo represent data.To make the data understandable. Maninder Kaur www.eazynotes.com 4
5. 5. Types of Data ModelsObject Based Data ModelsPhysical Data ModelsRecord Based Logical Data Models Maninder Kaur www.eazynotes.com 5
6. 6. Object Based Data ModelsIt use concepts such as entities, attributes and relationships.Types of Object Based Data Models: * Entity Relationship * Object Oriented * Semantic *Functional Maninder Kaur www.eazynotes.com 6
7. 7. Physical Data Models It describe how data is stored in thecomputer, representing information such asrecord structures, record ordering and accesspaths. Less no. of models are there. Maninder Kaur www.eazynotes.com 7
8. 8. Record Based Logical Data Modelso It is used to specify the overall logical structure of the database and to provide a higher-level description of the implementation.o Structured database in fixed formats. Maninder Kaur www.eazynotes.com 8
9. 9. Types of Record Based Data ModelsHierarchical ModelNetwork ModelRelational Model Maninder Kaur www.eazynotes.com 9
10. 10. Types of Record Based Data ModelsHierarchical ModelNetwork ModelRelational Model Maninder Kaur www.eazynotes.com 9