CS403 Highlighted Handouts by Asfand Yarr

Introduction to the course ............................................................................................................. 9 Database definitions: .................................................................................................................. 10 Importance of the Databases ..................................................................................................... 12 Databases and Traditional File Processing Systems ............................................................. 12 Advantages of Databases .......................................................................................................... 15

Difference between Data and Information ............................................................................... 17 Further Advantages of Database Systems: ............................................................................. 19 Cost Involved: .............................................................................................................................. 21 Importance of Data ...................................................................................................................... 22 Levels of Data .............................................................................................................................. 22 Users of Database Systems: ..................................................................................................... 24

Database Architecture: ............................................................................................................... 31 The Architecture: ......................................................................................................................... 33 External View (Level, Schema or Model): ................................................................................ 35 Conceptual or Logical View: ...................................................................................................... 37

Internal or Physical View / Schema .......................................................................................... 40 Data Independence: .................................................................................................................... 43 Functions of DBMS ..................................................................................................................... 45

Database Development Process ............................................................................................... 51 Preliminary Study: ....................................................................................................................... 51 Database Development Process: Approach 2 ........................................................................ 54 Tools Used for Database System Development: .................................................................... 56 Data Flow Diagrams: .................................................................................................................. 56 Types of DFD ............................................................................................................................... 60

Detailed Data Flow Diagram: ..................................................................................................... 63 Data Dictionary ............................................................................................................................ 64 Database Design Phase ............................................................................................................. 67 Data Model ................................................................................................................................... 68 Types of Data Models ................................................................................................................. 68 Types of Database Design ......................................................................................................... 69

Entity-Relationship Data Model ................................................................................................. 70 The Entity ...................................................................................................................................... 71 Classification of entity types....................................................................................................... 74 Attribute ......................................................................................................................................... 75 Types of Attributes ...................................................................................................................... 77 Summary: ..................................................................................................................................... 79 Exercises: ..................................................................................................................................... 79

Attributes ....................................................................................................................................... 80 The Keys ....................................................................................................................................... 80

Relationships ................................................................................................................................ 85 Types of Relationships ............................................................................................................... 87

Roles in Relationships ................................................................................................................ 95 Dependencies .............................................................................................................................. 97 Enhancements in E-R Data Model: .......................................................................................... 98 Super-type and Subtypes ........................................................................................................... 98 Summary: ..................................................................................................................................... 99

Inheritance Is ..............................................................................................................................100 Super types and Subtypes .......................................................................................................101 Specifying Constraints ..............................................................................................................103 Completeness Constraint .........................................................................................................103 Disjointness Constraint .............................................................................................................104 Subtype Discriminator ...............................................................................................................108

Steps in the Study of system ...................................................................................................110 Identification of Entity Types of the Examination System ....................................................118 Relationships and Cardinalities in between Entities .............................................................120 Conceptual Database Design ..................................................................................................122 Logical Database Design .........................................................................................................122 Conclusion ..................................................................................................................................123

Relational Data Model ..............................................................................................................125 Introduction to the Relational Data model ..............................................................................126 Mathematical Relations ............................................................................................................129 Database Relations ...................................................................................................................130 Summary.....................................................................................................................................130 Exercise: .....................................................................................................................................131

Database and Math Relations .................................................................................................132 Degree of a Relation .................................................................................................................133

Mapping Relationships .............................................................................................................140 Binary Relationships .................................................................................................................140 Unary Relationship ....................................................................................................................144 Data Manipulation Languages .................................................................................................146 Relational Algebra .....................................................................................................................147 Exercise: .....................................................................................................................................147

The Project Operator ................................................................................................................150

Types of Joins ............................................................................................................................157 Theta Join: ..................................................................................................................................157 Equi–Join: ...................................................................................................................................159 Natural Join: ...............................................................................................................................159

Semi Join: ...................................................................................................................................161 Relational Calculus ....................................................................................................................162 Tuple Oriented Relational Calculus: .......................................................................................162 Domain Oriented Relational Calculus: ...................................................................................162 Normalization .............................................................................................................................162