Data models

Data models

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  Mrs. Maninder Kaur [email protected] Maninder Kaur www.eazynotes.com 1
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  MODEL A Model isrepresentation 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
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  Components of DataModels 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
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  Purpose of DataModel To represent data. To make the data understandable. Maninder Kaur www.eazynotes.com 4
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  Types of DataModels Object Based Data Models Physical Data Models Record Based Logical Data Models Maninder Kaur www.eazynotes.com 5
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  Object Based DataModels 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
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  Physical Data Models  It describe how data is stored in the computer, representing information such as record structures, record ordering and access paths.  Less no. of models are there. Maninder Kaur www.eazynotes.com 7
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  Record Based LogicalData Models o 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
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  Types of RecordBased Data Models Hierarchical Model Network Model Relational Model Maninder Kaur www.eazynotes.com 9
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  Types of RecordBased Data Models Hierarchical Model Network Model Relational Model Maninder Kaur www.eazynotes.com 9