DATABASE MANAGEMENT SYSTEM DBMS By Prof Vinay S

DATABASE MANAGEMENT SYSTEM [DBMS] By Prof. Vinay S. Nalawade

Introduction To DBMS

Purpose Of Database System File Processing System • Data Redundancy • Data Inconsistency • Limited Data Sharing • Difficulty In Accessing Data • Data Dependance • Poor Data Control

• Security • Concurrency Problem • Poor Data Modelling • Data Isolation • Integrity Problem • Atomicity

Advantages of DBMS 1)Centralised Management 2)Reduction of Redudancies 3)Shared Data 4)Integrity 5)Security

6)Conflict Resolution 7)Data Independence

Disadvantages of DBMS 1)Complexity 2)Cost of S/W & H/W 3)Size 4)Upgrade/Replacement 5)Failure Impact 6)Performance

Database System Applications

VIEW OF DATA ABSTRACTION 1)Physical Level 2)Conceptual Level 3)View Level

Instances Database Schema Database Languages DDL DML – Procedural, Declarative

Data Models 1)Relational or Record Bases Model 2)Hierarchical Model 3)Network Model 4)Entity Relationship Model 5)Object Oriented Data Model 6)Physical Data Model

Database Design • Determining Data Relationships • Logical Structuring of Data • Avoiding Redundancy & Incompleteness

E-R Model • Entity & Entity Set - Strong & Weak Entity • Attribute - Single valued, Multi- valued, Simple, Composite, Derived

E-R Model • Relationships - Unary, Binary, Ternary, Quaternary

Constraints • Mapping Cardinalities - one to one, one to many, many to one, many to many • Participation Constraints - Total & Partial

Keys • Primary Key • Super Key • Candidate Key • Alternate Key • Composite Key

Database Design Process • Requirement Analysis • Conceptual Database Design • Choice of DBMS • Logical Database Design - System independent mapping

Database Design Process • Physical Design - Response Time - Space Utilization - Transaction Throughput • Implementation

• Entity Relationship Model • ER Diagram Entity-Rectangle Weak Entity-Double Rectangle Attribute-Eclipse Key Attribute-Eclipse with underline

• ER Diagram Multivalued Attribute-Double Eclipse Derived Attribute-Dashed Eclipse Relationship-Diamond Links-Line Double Line-Total participation of Entity

• ER Diagram Representations 1)Entity 7)Relationship 2)Weak Entity 3)Attribute 4)Key Attribute 5)Multi-valued Attribute 6)Derived Attribute

• ER Diagram Mapping Cardinality 1)One to One 2) One to Many 3)Many to One 4)Many to Many

• Design Issues 1)Use of Entity sets vs Attributes 2) Use of Entity sets vs Relationship sets 3)Binary vs n-arry Relationship sets 4)Placement of Relationship Attribute

• Extended ER Features 1. Specialization 2. Generalization Attribute Inheritance

Constraints On Generalization & Specialization - Condition defined, user defined - Disjoint, Overlapping - Completeness -Total or Partial • Aggregation

• Converting ER & EER Diagram into Tables