Database Systems - Introduction to Database Design (Chapter 4/1)

Database Systems - Introduction to Database Design (Chapter 4/1)

• 1.
  4. Database Design Techniques Inthis chapter you will be introduced to various techniques to design relational databases.
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  Database Design Topics -Importance of Database Design - Database Design Approaches - Database Design Phases - Data Modeling - Entity Relationship Data Modeling - Normalization - Conceptual Database Design - Logical Database Design - Physical Database Design
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  Importance of DatabaseDesign There are two primary approaches •Responsive applications •Enable you to extend database with ease •Sharing database for many applications •Integrity of data •Security of data
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  Database Design Methods Primarydesign methods are: •Bottom-up design method •Top-down design method
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  Importance of DatabaseDesign Proper design of database is crucial for •Responsive applications •Enable you to extend database with ease •Sharing database for many applications •Integrity of data •Security of data
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  Database Design Approaches Thedesign approaches are: •Bottom-up design approach •Top-down design approach
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  Bottom-up Database Design Stepsthat you should follow for this design approach are as follows: •Step-1: Identify attributes for which you need to store data •Step-2: Group the attributes into relations based on associations between the attributes through the process of normalization. Note:- Can be used only for small databases.
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  Top-down Database Design Stepsthat you should follow for this design approach are as follows: •Step-1: Create an Entity-Relationship Model •Step-2: Start with Entity Types of the Entity- Relationship Model as initial relations, apply normalization procedure to come up with the relations.
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  Database Design Phases Followingare the three phases of database design: •Conceptual Database Design •Logical Database Design •Physical Database Design
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  Conceptual Database Design Phase Input:Output of Systems Analysis – Data-Flow Diagrams, Software requirement specifications, etc. Output: Conceptual Data Model (ER-Model Diagram) Goal: To get a model capturing complete user data requirements, understand and represent relationships among entity types No implementation details to be shown.
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  Logical Database DesignPhase Input: Conceptual Data Model Output: A DBMS specific Data Model such as relation data model, hierarchical data model and network data model. No implementation details to be shown.
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  Physical Database DesignPhase Input: DBMS Specific Data Model Output: Database schema with implementation details such as physical organization of database objects, indexes to be used and location of the objects on secondary storage.