RDBMS UNIT 3 Diploma Fourth Semester ALL NOTES+ASSIGNMENT+PPT - DOWNLIAD AND LEARN - #DIGITALISEDATA

 

RDBMS UNIT 3 Diploma Fourth Semester ALL NOTES+ASSIGNMENT+PPT - DOWNLIAD AND LEARN - #DIGITALISEDATA

Notes

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PPT

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Assignment

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What is Data Modelling?

Data modeling (data modelling) is the process of creating a data model for the data to be stored in a database. This data model is a conceptual representation of Data objects, the associations between different data objects, and the rules. Data modeling helps in the visual representation of data and enforces business rules, regulatory compliances, and government policies on the data. Data Models ensure consistency in naming conventions, default values, semantics, and security while ensuring quality of the data.

Data Model

The Data Model is defined as an abstract model that organizes data description, data semantics, and consistency constraints of data. The data model emphasizes on what data is needed and how it should be organized instead of what operations will be performed on data. Data Model is like an architect's building plan, which helps to build conceptual models and set a relationship between data items.

The two types of Data Modeling Techniques are

1. Entity Relationship (E-R) Model
2. UML (Unified Modelling Language)

 

Why use Data Model?

The primary goal of using data model are:

• Ensures that all data objects required by the database are accurately represented. Omission of data will lead to creation of faulty reports and produce incorrect results.
• A data model helps design the database at the conceptual, physical and logical levels.
• Data Model structure helps to define the relational tables, primary and foreign keys and stored procedures.
• It provides a clear picture of the base data and can be used by database developers to create a physical database.
• It is also helpful to identify missing and redundant data.
• Though the initial creation of data model is labor and time consuming, in the long run, it makes your IT infrastructure upgrade and maintenance cheaper and faster.

Types of Data Models

Types of Data Models: There are mainly three different types of data models: conceptual data models, logical data models, and physical data models, and each one has a specific purpose. The data models are used to represent the data and how it is stored in the database and to set the relationship between data items.