CS 338: Computer Applications in Business: Databases (Fall 2014)

11992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

CS 338: Computer Applications in Business: DatabasesFall 2014

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welcome to

Eyhab Al-Masri

Course Information

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Term Class No. Section Lectures Location Lectures Time

Fall 2014 5712 LEC 001 DWE 1501 Wednesdays 10:00 am - 11:20 amFridays 10:00 am - 11:20 am

Instructor Name Office Email Office Hours

Eyhab Al-Masri, PhD DC 2555B ealmasri@uwaterloo.ca Wednesday 11:40 am 1:00 pm

TA Name Office Email Office Hours

Mina Farid TBA mfathy@uwaterloo.ca TBA

Abhishek Singhi TBA asinghi@uwaterloo.ca TBA

CS 338: Computer Applications in Business: Databases (Fall 2014)

21992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

about this course

Course Website UW LEARN Management System http://learn.uwaterloo.ca

Textbook Fundamentals of Database Systems

Authors: Ramez Elmasri & Shamkant Navathe Publisher: Addison-Wesley (2010) 6th Edition (5th edition may also work) ISBN: 0136086209

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Course Evaluation

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First midterm exam (Oct 10, in class) 25%

Second midterm exam (Nov 12, in class) 25%

Final Exam (TBA) 50%

Clicker Correctness [bonus factor of 4%] 4%

CS 338: Computer Applications in Business: Databases (Fall 2014)

31992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

Course Content

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Introduction to database systems

Relational data model

SQL (ad hoc queries)

Relational algebra

Views and view management

Entity-Relationship (ER) model

Extended ER model

Mapping ER models to relational

DBMS architecture

Transactions

Database security and privacy

Distributed databases

Data warehouses

Data analytics

Relational database principles

Data modeling

DBMS functionality

Related topics

Assignments

Three/four assignments throughout the term Sample solutions released on due date

Goal is to give you practice with material in orderto provide self-assessment and guidance

Assignment performance not part of evaluation You need not polish a submission You can work alone or with others You can seek help from TAs

You will have more trouble learning the material (and passing the course) if you do not attempt the assignments

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CS 338: Computer Applications in Business: Databases (Fall 2014)

41992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

Clickers

Wireless student response system

Active learning lasts longer than passive listening

Clicker questions allow you to show me what you understandwithout having to raise your hand and identify yourself

You will get some credit up to 4% bonus for correct answers (based on best 80%)

Bookstore ~$42 (return for ~$20)

Used $30 when available

Be sure to register your clicker here:http://www.student.cs.uwaterloo.ca/~pkates/uw-clicker.html

7Image Source: http://www1.iclicker.com/purchase-response-devices

Using Your Clicker

Turn it on:Press the ON/OFF button. A solid blue light should appear next to the top Power button. If your clicker came wrapped in packaging, pull out the small plastic tab on the back to activate the batteries.

Change the frequency to AA:The instructions on the back of your clicker say Press and hold the ON/OFF button until the top blue Power light flashes. Enter the 2 letter frequency code (AA).

The code for each classroom (AA for DWE 1501) is posted near the podium at the front of the class. When a clicker is turned off it forgets any changes in frequency and the clicker frequency is again AA when the clicker is turned on.

How do I know if my vote has been received?When the receiver acknowledges a vote, the Vote Status light on the clicker (the third light) will flash green for a moment. If it flashes red instead, then either the voting period hasn't started, or the receiver didn't respond to your vote. In the latter case, change the frequency of your clicker if necessary and vote again. Raise your hand for assistance if you don't see a green response.

Can I change my vote/choice?Yes. While the voting process is active, you can vote as often as you like. Only your last (most recent) choice/vote is recorded.

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CS 338: Computer Applications in Business: Databases (Fall 2014)

51992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

Summary

Be sure to check the course website regularly http://learn.uwaterloo.ca

Material builds on itself Like other courses in Math Initial lectures focus on terminology and background knowledge May be an overwhelming amount of details

Dont fall behind! If you have questions or concerns, please send me an email or talk to any of the

TAs I am always open to suggestions and recommendations

Do not cause a distraction9

Why Take A Database Course?

Database systems are at the core of Computer Science, Scientific Computing, Business, IT, Engineering, among many other disciplines

They are important to our society

Topic is intellectually rich

Good to have it on your resume

Easy to construct and use?

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This course is designed primarily to meet the needs ofstudents who are interested in the business or publicsector of the economy. The course presents methods usedfor the storage, selection, and presentation of data.

CS 338: Computer Applications in Business: Databases (Fall 2014)

61992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

Why Take A Database Course? at the core of many disciplines

Database systems have become in recent years an essential component

Daily life activities involve some interaction with a database Shift in corporate strategies (i.e. standalone applications to

Web applications)

Need for database technology has increased significantly Web: vast pool of information Examples:

Search engines, Wikis, Web Services, Electronic Commerce, Social Networks, etc

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Why Take A Database Course? they are important to our society

Knowledge is power Sir Francis Bacon

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CS 338: Computer Applications in Business: Databases (Fall 2014)

71992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

Why Take A Database Course? topic is intellectually rich

Information Representation Database modeling/design

Languages and Data Queries Complex queries

Concurrency Control Controlling concurrent access to information

Data Mining Discovering patterns in data

Data Storage Software & hardware that can fit large amounts of data

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Why Take A Database Course? good to have it on your resume

Database systems are applied across many areas Electrical Engineering Software Development Mechanical Engineering Computer Science Science Business among many others

Valuable in situations such as Use database (DB) terminology knowledgeably Understand DB concepts that arise in the workplace Interact with (direct, understand) IT personnel Understand technical articles involving DB technology Discuss DB concepts in a job interview

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CS 338: Computer Applications in Business: Databases (Fall 2014)

81992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

Why Take A Database Course? easy to construct and use?

Developing a database may involve a great amount of work

Good News: This is an introductory course Course workload is balanced throughout the semester

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Databases and Database UsersChapter 1

1992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Some material adapted and modified from Fundamentals of Database Systems (Elmasri et al.) Rice University Data Center

CS 338: Computer Applications in Business: Databases (Fall 2014)

91992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

what is a database?

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Introduction

Database Collection of related data Data known facts that can be recorded and that have implicit meaning

A database has the following implicit properties Miniworld or universe of discourse (UoD) Represents some aspect of the real world Changes in the miniworld are reflected in the database

Logically coherent collection of data with inherent meaning Random assortment of data cannot be referred to as database

Designed, built and populated with data for a specific purpose

Diff between database and collection of data is that it relates to real world

CS 338: Computer Applications in Business: Databases (Fall 2014)

101992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

Introduction

Example of a large commercial database Amazon.com, eBay, Facebook, Twitter

Database Management System (DBMS) Collection of interrelated data and programs that enable users to

create and maintain a database

DBMS is a general-purpose software system that facilitates the processes of defining, constructing, manipulating, and sharingdatabases among various users and applications Allows multiple users/programs to access and manipulate DB

concurrently

Protects DB against unauthorized access and manipulation

Provides means to evolve DB and program behaviour as requirements change over time

Introduction Basic Functions of DBMS

Defining a database Specify the data types, structures, and constraints of the data to be

stored Uses a Data Definition Language (DDL) Meta-data Database definition or descriptive information Stored by the DBMS in the form of a database catalog or dictionary

Constructing a database Process of storing data on some storage medium controlled by the

DBMS

CS 338: Computer Applications in Business: Databases (Fall 2014)

111992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

Introduction Basic Functions of DBMS

Manipulating a database Query and update the database miniworld Generate reports Uses Data Manipulation Language (DML)

Sharing a database Allow multiple users and programs to access the database

simultaneously

Introduction Basic Functions of DBMS

Populating a database Inserting data to reflect the miniworld

Application program Accesses database by sending queries to DBMS

Query Causes some data to be retrieved

e.g. retrieve bank account balance

Transaction May cause some data to be read and some data to be written into the

database e.g., buying a product, transferring funds

CS 338: Computer Applications in Business: Databases (Fall 2014)

121992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

Introduction Basic Functions of DBMS

Protecting a database System protection against hardware or software malfunction (i.e. crashes)

Security protection against unauthorized or malicious access

Maintaining a database Allow the system to evolve as requirements change over time

An Example

UNIVERSITY database Information concerning students, courses, and grades in a university

environment

Data records STUDENT COURSE SECTION GRADE_REPORT PREREQUISITE

Define structure of each type of data record by specifying data elements to include and data type for each element

String (sequence of alphabetic characters)Numeric (integer or real)Date (year or year-month-day)Monetary amountetc.

Very important

CS 338: Computer Applications in Business: Databases (Fall 2014)

131992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

An Example

An Example Simplified Database System Environment

Data Definition Language (DDL)

Structured Query Language (SQL)

Data Manipulation Language (DML)

DBMS must ensure that only authorized users access database.

CS 338: Computer Applications in Business: Databases (Fall 2014)

141992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

To construct the UNIVERSITY database Store data to represent each student, course, section, grade report,

and prerequisite as a record in appropriate file

Define relationships among the records Example: record for Smith in the STUDENT file is related to two

records in the GRADE_REPORT file Specifies Smiths grades in two sections or courses

Database manipulation involves querying and updating

An Example

Examples of queries:

Retrieve the transcript a list of all courses and grades of Smith

List the names of students who took the section of the Database course offered in fall 2008 and their grades in that section

List the prerequisites of the Database course

An Example

CS 338: Computer Applications in Business: Databases (Fall 2014)

151992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

Examples of updates:

Change the class of Smith to sophomore

Create a new section for the Database course for this semester

Enter a grade of A for Smith in the Database section of last semester

Queries and updates must be specified precisely in the query language of the DBMS before they can be processed

An Example

Phases for designing a database:

Requirements specification and analysis

Documented in details

Conceptual design

Represented and manipulated using some computerized tools

Logical design

Expressed in a data model (i.e. Relational Data Model)

Physical design

Further specifications are provided for storing and accessing the database

An Example Phases for Designing a Database

CS 338: Computer Applications in Business: Databases (Fall 2014)

161992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

Before Database Approach Traditional File Approach

Traditional file processing

Each user defines and implements the files needed for a specific software application

System stores permanent records in various files it needs different programs to extract records from, and add records to,

the appropriate files

Before Database Approach Traditional File Approach

Registrar Office Application

Example

Registrar Office Files

Accounting Office Files

Accounting Office

Application

Registrar Office Users

Accounting Office Users

.

..

.

..

CS 338: Computer Applications in Business: Databases (Fall 2014)

171992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

Disadvantages1. Uncontrolled Redundancy & data inconsistency

No form of supervision that can coordinate data operations

2. Poor Enforcement of Standards Data names, formats, constraints, etc..

are not standardized across an organization

Before Database Approach Traditional File Approach

Disadvantages3. Limited data sharing

Each application has access only to its files (i.e. other applications do not have access to these files)

4. Program-Data Dependency Any change to structure causes change

in all programs accessing that file Description of files and data are

embedded within an application

Before Database Approach Traditional File Approach

Also any changes in structure must

CS 338: Computer Applications in Business: Databases (Fall 2014)

181992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

Database Approach

Database approach Overcomes the limitations of the traditional file approach Single repository maintains data that is defined once and then

accessed by various users

Main characteristics of database approach 1. Self-describing nature of a database system2. Insulation between programs and data, and data abstraction3. Support of multiple views of the data4. Sharing of data and multiuser transaction processing

Database Approach

Registrar Office Application

Example

Common Shared

Database

Accounting Office

Application

Registrar Office Users

Accounting Office Users

.

..

.

..

CS 338: Computer Applications in Business: Databases (Fall 2014)

191992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

1. Persistence of data2. Transaction control3. Concurrency control4. Recovery control5. Querying6. Integrity control7. Data security8. Version control9. Performance tuning

A DBMS in the Database Approach allows

Characteristics of database approach Self-Describing Nature of a Database System

Database system contains complete definition of structure and constraints This information (called meta-data) is stored in the DBMS catalog

i.e. structure of each file, type and storage format of each data item, various constraints on data

Database catalog used by: DBMS software Database users who need information

about database structure

DBMS software is not written for a specific database

application

CS 338: Computer Applications in Business: Databases (Fall 2014)

201992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

Characteristics of database approach Self-Describing Nature of a Database System

Characteristics of database approach Insulation Between Programs and Data

Database systems have Program-data independence

Structure of data files is stored in DBMS catalog separately from access programs

Changes made to the structure of the database does not necessarily require changes to the programs (i.e. add new columns)

Program-operation independence Some types of database systems enable definitions of operations on

data as part of database definitions

Operations are specified in two parts:

Interface (or signature) includes operation name and data types of its arguments

Implementation (or method) can be changed without affecting the interface

CS 338: Computer Applications in Business: Databases (Fall 2014)

211992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

The characteristic that allows program-data independence and program-operation independence is called data abstraction

DBMS provides users with conceptual representation of data Does not include many of the details of how data is stored or how

operations are implemented

Data model Type of data abstraction used to provide conceptual representation It uses logical concepts such as objects, their properties, and their

interrelationships Hides implementation and storage details

Characteristics of database approach Insulation Between Programs and Data

Characteristics of database approach Support of Multiple Views of the Data

View Subset of the database, or Contain virtual data derived from the database files but is not

explicitly stored

Multiuser DBMS Users have a variety of distinct applications Must provide facilities for defining multiple views

Can also limit number of users allowed to access data

Ex. API's, such as Ebay's API to allow 3rd party plug-ins to use their software without the code itself

Create as many views as you wish

CS 338: Computer Applications in Business: Databases (Fall 2014)

221992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

Characteristics of database approach Support of Multiple Views of the Data

Characteristics of database approach Sharing of Data & Multiuser Transaction Processing

Allow multiple users to access the database at the same time Example assigning seats for airline reservation systems

Concurrency control software Ensure that several users trying to update the same data do so in a

controlled manner Result of the updates is correct

Online transaction processing (OLTP) application Ensure that concurrent transactions operate correctly and efficiently

CS 338: Computer Applications in Business: Databases (Fall 2014)

231992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

Transaction Definition: executing program or process that includes one or more

database accesses (i.e. reading or updating records)

DBMS must enforce some properties Isolation property

Each transaction appears to execute in isolation from other transactions

Atomicity property Either all the database operations in a transaction are executed or none

are

Characteristics of database approach Sharing of Data & Multiuser Transaction Processing

Data Centers

46Picture from Rice University: Data Center

CS 338: Computer Applications in Business: Databases (Fall 2014)

241992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

Data Centers

47Picture from Microsoft: Data Center (Ireland)

Data Centers

48Picture from Google : Council Bluffs (Iowa)

CS 338: Computer Applications in Business: Databases (Fall 2014)

251992-2014 by Addison Wesley & Pearson Education, Inc., McGraw-Hill. Somematerial adapted and modified from Fundamentals of Database Systems (Elmasri et al.)

Data Centers

Interested in getting more information about current Google Data Centers? Check http://www.google.com/about/datacenters/

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