CSE3180 Semester 1,2005. Lect 1 / 1 Welcome to CSE3180 ‘Principles of Database Systems’ First Semester 2005 ThisNOT This

CSE3180 Semester 1,2005. Lect 1 / 1

Welcome to CSE3180 ‘Principles of Database Systems’ First Semester 2005

This NOT This


Introduction to CSE3180Introduction to CSE3180

This unit covers many aspects associated with database, and in this series of lectures, those related to Relational Data Base (but not exclusively)

I’m : Rod Simpson

My Office is : Room C 4.46

My Phone contact number is : (03)990 32352

My email is [email protected]

My contact times are very limited as I’m running another unit concurrently.


Which stands for

School of Computer Science and Software Engineering

Faculty of Information Technology


The Time TableThe Time Table

Laboratory Sessions will take place from

9.30am to midday

• Monday, November 22nd to Wednesday November 24th• Monday, November 29th to Wednesday December 1st• Monday, December 6th to Wednesday December 8th• The laboratories are

• The examination will be held on Friday 10th December from 1.30pm to 3.45pm


AssessmentAssessment

A 2 hour written examination Friday 10th December) Contribution 50%

A 2 part assignment Contribution 50%

- 5 short questions on database related terms and

application (15%)

- The development of a database and queries

relative to Monash University Laboratory facilities (35%)



Lectures will take place from

1.00pm to 4.00pm

• Monday, November 22nd to Wednesday November 24th• Monday, December 29th to Wednesday December 1st • Monday, December 6th to Wednesday December 8th



No relationship


PRINCIPLES OF DATABASEPRINCIPLES OF DATABASEPRINCIPLES OF DATABASEPRINCIPLES OF DATABASE


Introduction Part 2Introduction Part 2

Special and Important Notice

Today is the LAST DAY for withdrawing from this

unit without penalty



The notes for this unit can be found on the Monash Web Page at this address:

http://www.csse.monash.edu.au/courseware/cse3180s

The overheads are in PowerPoint (Office 97) format and can be viewed on the File Server software.

There are other notes and papers in Microsoft Word


Lecture ObjectivesLecture Objectives

• This lecture will cover:

– some thoughts on data storage and retrieval constraints

– what is the form of the ‘data’

– some definitions of ‘data’, ‘information’, ‘audit trail’

– what is a data base - who would want one


Lecture ObjectivesLecture Objectives

– some of the functions of the database management software

– different models (commercial)

– the relational model

– advantages and disadvantages of database– – some practical aspects of your assignment



Course Outline

As you will see from the notes, the recommended text is Hoffer, Prescott and McFadden’s ‘Database Management’.

Edition 7.

The examples and the exercises at the end of most chapters are well worth a read, and they form the basis of the examination questions (the exam is scheduled for Friday 12th December)

Another recommended text is Thomas Connolly and Caroline Beggs ‘DataBase Systems’ 3rd Edition.



There is one assignment, with 2 Parts, and it is expected that you will work in groups - your tutors should have arranged that this morning.

The assignment support software is either Oracle or MS Access. If you wish to use some other DBMS, (such as SQLServer or MySQL) you will need to come to some amicable arrangement with your tutor


IntroductionIntroduction

Features of database such as

– Recovery – Security – Consistency– Concurrency– Database Management architecture– Background processes

will be based on Oracle’s version 8i. You will be using a 9i client in the labs.


DatabaseDatabase

This morning’s exercise would have alerted you to the need to understand what requirements are made of data analyses, who needs these analyses, when and in what form.

In all this there is an expectation that the results of ‘queries’, which is the same as saying data supported by the database, is accurate, timely and complete.

In these lectures, you will see how these requirements can be built into a database - as you will do with your database model.

And that is what it is - a model which accurately reflects data as it occurs and is processed in the ‘real world’.


Some Thoughts on Data StorageSome Thoughts on Data Storage

• A major benefit of Computing is the ability to STORE and RETRIEVE large amounts of data

• However, there are a number of processes and other considerations which need to be worked together to maximise this benefit

• Some very early items are– What data ?– What are its sources ?– What are the volumes /frequency ?– How long is to be stored and Why this period ?– In what FORM is it to be stored ?


Some Thoughts on Data RetrievalSome Thoughts on Data Retrieval

• Who is going to ‘access’ (retrieve or query) this data ?

• How often ?

• From where ?

• Why is data to be accessed - for what purpose ?


Some Thoughts on Data RetrievalSome Thoughts on Data Retrieval

• How is it to be accessed ? Voice inquiry, remote, by formal request, normal processing schedule, randomly, whenever the ‘need’ arises ?

• Is the data to be freely available ?– Are there some limitations on access ?– How are these access limitations managed ?

• What value is inherent in the data ?


Some General ThoughtsSome General Thoughts

• What time base or volume spread is to be represented by the data ?

• What levels of accuracy are to be expected ?

• Is data to be available 7 days a week, 24 hours/day ? (24x7)

• What response time is expected ? Minimum ? / Tolerable ?

And just what does that mean in real value terms ?

• How is new or altered data to be directed to existing data ?


Some General ThoughtsSome General Thoughts

• How is input access to be controlled ?

• When and why is data deleted - who authorises such deletions ?

• What does the ‘data’ consist of - characters, objects, audio visual, TV, audio, animation ?

• What is the optimum method of storage (organisation) ?


Some DefinitionsSome Definitions

A General Definition:

DATA - raw (unprocessed or partly processed) facts which represent the state of entities (things) which

have occurred

INFORMATION - data which has been processed into a form USEFUL TO THE USER /STAKEHOLDER

What is Information to one user may be Data to another user.


Possible influence of ABC Channel 2 ?


Audit TrailAudit Trail

General Definition:

‘The presence of data processing media and procedures

which allow any and / or all transaction(s) to be traced

through ALL STAGES of processing’

This infers that the following devices / techniques are in place:

1. A logging device which ‘traps’ all transactions

2. Some way of tagging each transaction so that it can be identified

3. Some way of retrieving the required transaction(s)

4. Some way of archiving - what is the required period ?

5. Control procedures and processes to ensure integrity


DatabaseDatabase

A Database is a shared collection of Inter-Related data designed to meet the needs of multiple types of users and applications.

This implies that multiple user VIEWS can be defined

Data stored is independent of the programs which use it

Data is structured to provide a basis for future applications

DATABASE = Stored Collection of Related Data May be physically distributed


Database Management SoftwareDatabase Management Software

A DBMS is SOFTWARE which provides access to the database in an integrated and controlled manner

A DBMS must contain :

1. Data Definition and Structure capabilities

2. Data Manipulation capabilities


Data Definition and ManipulationData Definition and Manipulation

Data Definition Language (DDL)

used to describe data at the database level

Schema level - complete database description

Sub-Schema level - user views (restricted)

Data Manipulation Language (DML)

Provides for these Create Insert

capabilities Update Retrieve (extract)

Delete Drop

Modify Calculation

Report



The Many Faces of DatabaseThe Many Faces of Database

Databases can be:

1. Transaction Intensive - ATM’s Checkouts

2. Decision Support - Browsing for trends

3. Mixed-Load - Combination of both

4. Small databases - Few thousand records

5. Very Large Database - Many millions or trillions

(VLDB) of records (Banks)

6. Non Traditional - Weather bureau, flight plans

Computer Aided Design data

7. Mobile - Able to ‘move around’


DBMS RequirementsDBMS Requirements

Querying Capabilities

Data Displays (Presentation)

Data entry

Data Validation

Data Deletion

Committing Procedures (of changes)

AND Data Integrity, Security, Consistency and Concurrency Capabilities



• They can be:

Data Warehouses

Data Marts (or martlets)

• How is a database size measured ?

There are a number of ‘measurements’

Raw data size

Total database size

Total usable disk space size (which includes media protection such as mirroring)



Hardware Database Raw Data Total Disk

HP9000 Oracle 100GB 643GBDigital 8400 Oracle 100GB 361GB

IBM SP2 DB2/6000 100GB 377GB

NCR5100 Teradata 100GB 880GB

NCR5100 Teradata 1,000GB 3,280GB


Important Database FeaturesImportant Database Features

• Data Integrity• Data Independence• Referential Integrity - Relational Database Model• Concurrency Control - Multiple Users• Consistency

- multi users

- distributed database

- replicated database

- partitioned database

- mobile database• Recovery from failure (Transaction and Media)• Security


owner / parent

child / parent

child / parent

owner

member

Data Base Models - HierarchicalData Base Models - Hierarchical

child


Data Base Models - NetworkData Base Models - Network

set of data

owner

member

Note: Only linked sets can be accessed

set ofdata

member

owner


Data Base Models - NetworkData Base Models - Network

set of data

owner

member

Note: Only linked sets can be accessed

set ofdata


Data Base Models - RelationalData Base Models - Relational

table table table table table A B C D E

Any table(s) can be joined to any other table(s), provided there is a means of effecting the join

Primary key / Foreign key concept. Data redundancy

No fixed linkages


A quick introduction to the developer ofthe Relational Data Base

The late Dr. E. Codd


A Primary Key - What’s that ?A Primary Key - What’s that ?

• Hoffer, Prescott and McFadden define a Primary Key as :

An attribute (or combination of attributes) which uniquely identifies each row in a relation. (table)

• Richard T. Watson has this to say:

The primary key definition block specifies a set of column values comprising the primary key. Once a Primary Key is defined, the system enforces its uniqueness by checking that the Primary Key of any new row does not already exist in the table.


And - A Foreign Key ??And - A Foreign Key ??

• Hoffer, Prescott and McFadden’s definition:

An attribute (or attributes) in a relation (table) of a database which serves as the Primary Key of another relation (table) in the same database.

• Richard T. Watson says:

An attribute (or attributes) that is a Primary Key in the same table, or another table. It is the method of recording relations in a relational database.

And, both the Primary and Foreign Key(s) should be drawn from the same Domain.


2 relations2 relations

EMPNUM NAME Date of Birth DEPTNUM 3 JONES 16-05-1956 605 Referencing 7 SMITH 23-09-1965 432 Table 11 ADAMS 11-08-1972 201 15 NGUYEN 23-10-1964 314 18 PHAN 16-11-1976 201 23 SMITH 19-09-1974 314Relation (Table) Name : EMPRelation Schema: EMP(empnum,name,date of birth,deptnum)

DEPTNUM DEPTNAME201 Production314 Finance432 Information Systems605 Administration

Relation (Table) Name : DEPTRelation Schema: DEPT(deptnum, deptname)

ReferencedTable


What are these ?What are these ?

EMP DEPT

An Employee MUST be associated with one Department

Must a Department have AT LEAST one Employee ?Or can there be More Than 1 Employee ?Can there be a Department with NO employees ?

Employee Details are :Employee Number, Employee Name, Date of Birth and the Department Code the Employee works in.

Department Details are Department Number and Department Name

They are theEntities


Relational DatabaseRelational Database

Data is represented in ROW and COLUMN form (matrix)

(tuple) (attribute)

Collections of related data ---> TABLES (relations)

1 or more tables ----> DATA BASE

ATTRIBUTES are generally static

ROWS are DYNAMIC and Time-Varying

The number of Attributes = DEGREE of a table

The number of Rows = CARDINALITY of a table


Some RDB ConsiderationsSome RDB Considerations

• Data is held in tables• No order of data in tables - row or attribute• Concept of Foreign Key - Primary Key relationship• Data Typing (number, character ..) - including nulls• Query Access - insert, update, delete, retrieval• Indexing on candidate (and Primary) keys• Integrity Constraints

Attribute value ranges

Referential Integrity (Foreign Key - Primary Key)

Entity Integrity

User Defined Integrity• ‘Sets of Data’ retention constraints


Some RDB ConsiderationsSome RDB Considerations

• Domain constraints• User defined ‘Rules’ e.g. quantities and values must not be

negative; pricing rate must not be zero• Recovery procedures• No explicit linkages between tables• Linking or embedding database operations in a procedural

language (Cobol, C ..)• Databases may be distributed across similar or different

DBMS’s• Security features


Database ComponentsDatabase Components

1. Back End Engine

Used for Disk Input/Output processes

(Read/Write/Find)

2. Front End Processor

Data manipulation

String/Arithmetic/Statistical operations

3. DBMS Interface

Data Definition Language (DDL)Data Manipulation Language (DML)

4.Programmer Interface

Applications Environment (4GL’s, Embedded capability)


Data Description LanguageData Description Language

Used to describe data at the Database level

Structure: Attributes

Schema : Complete description of the database using DDL

SubSchema : Describes data in the database as it is ‘known’ to individual programs(processes) or users

The segment of logical data record(s) required is

commonly known as a VIEW


Data Manipulation LanguageData Manipulation Language

Language (commands and syntax) used to cause transfers of data from the Database and the Operating Environment and vice versa

Variety of Languages - Cobol, C, Java,

and SQL as in Access, DB2, dBASEV, Informix, Oracle, VisualDataBase, SQLServer, MySQL

Windows versions provide Icons and Menu options which are translated by the DBMS software to Database manipulation commands

Typical functions: get, put, replace, seek, update,delete, insert, drop, find, modify


A Typical Database ModelA Typical Database Model

Users - keyboard directDBMS

Database

Users

MenuOptions

Program

Interface

Programs written inCobol, C, C++, PascalJava etc.

Database QueryAccess Language


Advantages of DatabaseAdvantages of Database

• Reduced Data Redundancy

• Data Integrity

• Data Independence

• Data Security

• Data Consistency

• Easier use of Data via DBMS Tools (Query languages, 4GL's)


Disadvantages of DatabaseDisadvantages of Database

• Complexity

• Expense

• Vulnerability

• Size of - disk storage, processor memory

• Training Costs

• Compatibility

• Technology Lock In


More on DBMSMore on DBMS

Capabilities Required:– the DBMS must provide a natural interface of user data– the interface must be independent of any physical

storage structures– different users with different views must be able to

access the same database– database changes must be possible without affecting

programs which do not use the changes

(Physical and Logical Independence)


More on DBMSMore on DBMS

Other Requirements : Provision of Operational Facilities to ensure:– multi user access control– remote terminal access– restrictions on user access– recovery from system faults– database distribution


Overview of DataBase Overview of DataBase

Data Creation

Reliability, Content,Completeness

Good Data Input to Database Tables

DataBaseSubject to :AuditTime RelevanceAdvanced Business RulesNew DBMSNew ApplicationsAltered Business RulesAssociated with other Business Applications

UsersPeople, Other SystemsWeb based Access

SCMBPMCRM…..


Overview of DataBaseOverview of DataBase

Legacy Data Current

from Legacy Systems DataBases

DataWarehousing Processes

Data Mining

Business Based Performance Analyses


Your AssignmentYour Assignment

• Intended to bring together many of the aspects required in DATABASE DESIGN

• It is NOT a complete systems design

• There is no transaction processing required

• The database MUST contain accurate existing data

• It must exhibit constraints and other forms of data integrity



The AssignmentThe Assignment

Part 1 consists of 5 questions. The intention is to give you familiarity of some of the database terms and environment

Part 2 is directed at your developing a database of the Laboratory Devices of Monash University.

It probably sounds relatively easy, but don’t be misled.

You will need to develop ‘Business Rules’ and these will lead to ‘constraints’ which will effectively be part of the database contents.


The AssignmentThe Assignment

And you will need to curb your energies in designing the database and its outputs (which should be your first consideration).

You have only 3 weeks to plan, design, construct and have your database operational.



• The 2 Parts are designed to give you some understanding of the design requirements of a database - and this means of course, understanding the specific details which the database must address

• In Part 2 of the assignment (the model), YOU are the user– You set the ground rules, also known as Business Rules– You need to document these Rules– Don’t make the project too onerous i.e. make the design

simple.– That way you will complete both Part 1 and Part 2 in the

short period we have



• Part 1 - Analysis and Solution

Due Tuesday 30th November

(Tuesday week )

• Part 2 - The Details of the University’s Laboratory Inventory

Due 8th December - final tutorial session



• One of the group members will need to be the Co-ordinator

- do this co-operatively.

• Also, some person in the group will need to address the question of documentation !!!

• Use of Microsoft Word would be an advantage.



• Part 1 - :– This sets the tempo for the assignment– Make sure you understand the MAJOR aspects

• By Wednesday, 24th November you should have some workable ideas about the rest of the assignment - and you should have done some reading or consulting with your tutor regarding the 5 questions


Part 1Part 1

For Part 1, there is no code required. The questions are there to provide you with a kick-start mechanism to come to grips with database and its world

For Part 2, you will need

1.To understand the nature of the problem

2. Develop scenarios - successful and unsuccessful

3. Verify the scenarios

4. Modify - if or when necessary

5. Develop the ‘Business Rules’

- what combinations can exist / cannot exist

- how to control sequences

- what checks must be embedded to ensure accuracy



One member will need to act as the Reviewer for

– Completeness of both Part 1 and Part 2

– Validity of the Comments made

– Validity of the Entity Relationships

– Normalisation / Primary key(s) / Foreign key(s)


Your Assignment - Part 2Your Assignment - Part 2

For Part 2 you will need to develop :– Data structures

– Constraints

– Test strategy

– Test data

– Testing results

– Operational model


Your Assignment - Part 2Your Assignment - Part 2

• Make rough outlines of the model of your database

Entities plus their relationships (connectivities)

• Make rough outlines of any changes to the the Data Structures - these expand and show the attributes of the Entities

• Make notes of Rules, and the Constraints, you consider will help the Rules to control data in your database for both existing and future users



• Review the E-R diagram critically - it’s best if one person of the group becomes the ‘Quality Control’.

• Each member of the group MUST know what the assignment is about and how it is is being developed.

• Prepare the ‘final’ technical paper for Part 1 by Wednesday 1st December

• Complete the database, and produce the analyses, by Wednesday 8th December



• You will (probably) be using MS-Access to develop the physical database. Or, you could use Oracle. Or SQLServer (but check with your Tutor)

• Become familiar with the Table Design feature– Include Primary Keys, Required Fields, Value Ranges or

Exclusions– ‘Numbers’ are ??

– Integers (no decimals)– Numerics with decimals– Text references only

• Use data types to constrain data• Use the ‘required’ property in Access or the ‘not null’ type in

Oracle



• There should be no need to delve into the Applications Development features of the DBMS. However, if you have some expertise, and time, do so by all means

• Make sure you keep a backup of your database


Building EvacuationBuilding Evacuation

If the Building Evacuation Alarm System Activates

– Collect your belongings– Move out of the room using the Exits– Use the Stairs - NOT the Lifts or Escalators– Follow the directions of FLOOR WARDENS - if present– Move to the Lawn outside K Block (common)– Wait for further instructions (if during the evening use

your discretion)

– TREAT EVERY EVACUATION ALERT as REAL



Laboratory Sessions will take place from

9.30am to midday

• Monday, November 22nd to Wednesday November 24th• Monday, November 29th to Wednesday December 1st • Monday, December 6th to Wednesday December 8th



That should be enough for today

The website :http://www.csse.monash.edu.au/courseware/cse3180s

and make sure you reference cse3180s

Documents

CSE3180 Semester 1,2005. Lect 1 / 1 Welcome to CSE3180 ‘Principles of Database Systems’ First Semester 2005 ThisNOT This