intro to databases

1. Intro to Databases
Instructor: Malik M. Ali Shahid
First Session: Introduction

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Purpose of this course
 An introduction to database
management systems
 Help students understand the benefits
that can be attained by using
Relational DBMS
 Enable students to become comfortable
in designing database schemas in SQL,
plus writing CRUD functions

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Course Summary
 This course covers these topics:
 Introduction to Databases & their users
 DBMS Concepts & Architecture
 Data Modeling using the ERM
 Relational Data Model & Algebra
 SQL (Schemas, Queries, Constraints)
 Functional Dependencies
 Normalization

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Course Books
 Primary Text:
 An Introduction to Database Systems – 8e.
 By C. J. Date
 Reference Text:
 Fundamentals of Database Systems – 4e.
 By Ramez Elmasri and S. B. Navathe

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Grading (tentatively)
 Assignments : 10%
 Quizzes: 10%
 Project : 10%
 Lab: 10%
 Midterm Exam : 20%
 Final Exam : 40%

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What was the need for Databases?
 The concept of a file system is where
our story begins
 Everything was done one way
 “Master Files” held information
 “Transaction Files” told the file system
what to do
 “New Master File” was created in place of
the old one
 “Error Files” stored what went wrong
 These were used for a very long time

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The File System
Transaction
File
Master File New Master File
Error
Log

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What was wrong with file system
approach?
 Too much programming knowledge
necessary
 Everyone who used them had to have a fairly
technical background
 In order to transact much of what was done you
had to know a lot about the system and files
 Took a good while to get information to where it
needed to go
 Hard to secure
 Integrity was hard to enforce
 Too much room for error
 Just not easy enough for corporations

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Now with Databases
 Built-in Support for
 Security & Access Control
 Constraints & Triggers
 Transactions
 Performance Tuning

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What is a Database?
 Basic Definition
 A Database is a collection of data files
 Complex Definition
 A Database is a structure that contains
information about many kinds of entities
and about the relationships between
those entities.

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Entities
 Entity – a person, place, thing, or event
 Entities become our categories of
information
 Customers
 Products
 Orders
 We organize our information in these major
entities (categories)
 These categories become the tables, that
will store our data

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Relationships
 Relationship – an association between
entities
 Relationships define how our data
files will talk to each other
 Customers “Place” Orders
 Orders “Are For” Products
 There are several key types of
relationships that we will talk about
later on

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More about Entities
 What does everyone have in common?
 Entities have basic properties too
 Properties of entities are called Attributes
 Attributes describe our categories
 A “Customer” has some basic properties
 Name
 Phone Number
 Address