Transcript Principles of Database - Pravin Shetty > Resume

Welcome to CSE3180
‘Principles of Database Systems’
First Semester 2005
This
NOT This 
CSE3180 Semester 1,2005. Lect 1 / 1
Introduction 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.
CSE3180 Semester 1,2005. Lect 1 / 2
Which stands for
School of Computer Science and Software Engineering
Faculty of Information Technology
CSE3180 Semester 1,2005. Lect 1 / 3
The 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
CSE3180 Semester 1,2005. Lect 1 / 4
Assessment
A 2 hour written examination
December) Contribution 50%
Friday 10th
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%)
CSE3180 Semester 1,2005. Lect 1 / 5
The Time Table
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
• The examination will be held on Friday 10th December from
1.30pm to 3.45pm
CSE3180 Semester 1,2005. Lect 1 / 6
No relationship
CSE3180 Semester 1,2005. Lect 1 / 7
PRINCIPLES OF DATABASE
CSE3180 Semester 1,2005. Lect 1 / 8
Introduction
Part 2
Special and Important Notice
Today is the LAST DAY for withdrawing from this
unit without penalty
CSE3180 Semester 1,2005. Lect 1 / 9
Introduction
Part 3
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
CSE3180 Semester 1,2005. Lect 1 / 10
Lecture 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
CSE3180 Semester 1,2005. Lect 1 / 11
Lecture 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
CSE3180 Semester 1,2005. Lect 1 / 12
Introduction
Part 4
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.
CSE3180 Semester 1,2005. Lect 1 / 13
Introduction
Part 4
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
CSE3180 Semester 1,2005. Lect 1 / 14
Introduction
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.
CSE3180 Semester 1,2005. Lect 1 / 15
Database
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’.
CSE3180 Semester 1,2005. Lect 1 / 16
Some 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 ?
CSE3180 Semester 1,2005. Lect 1 / 17
Some 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 ?
CSE3180 Semester 1,2005. Lect 1 / 18
Some 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 ?
CSE3180 Semester 1,2005. Lect 1 / 19
Some 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 ?
CSE3180 Semester 1,2005. Lect 1 / 20
Some 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) ?
CSE3180 Semester 1,2005. Lect 1 / 21
Some 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.
CSE3180 Semester 1,2005. Lect 1 / 22
Possible influence of ABC Channel 2 ?
CSE3180 Semester 1,2005. Lect 1 / 23
Audit 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
CSE3180 Semester 1,2005. Lect 1 / 24
Database
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
CSE3180 Semester 1,2005. Lect 1 / 25
Database 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
CSE3180 Semester 1,2005. Lect 1 / 26
Data 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
capabilities
Update
Delete
Modify
Report
Insert
Retrieve (extract)
Drop
Calculation
CSE3180 Semester 1,2005. Lect 1 / 27
CSE3180 Semester 1,2005. Lect 1 / 28
The Many Faces of Database
Databases can be:
1. Transaction Intensive
2. Decision Support
3. Mixed-Load
4. Small databases
5. Very Large Database
(VLDB)
6. Non Traditional
7. Mobile
ATM’s Checkouts
Browsing for trends
Combination of both
Few thousand records
Many millions or trillions
of records (Banks)
- Weather bureau, flight plans
Computer Aided Design data
- Able to ‘move around’
-
CSE3180 Semester 1,2005. Lect 1 / 29
DBMS Requirements
Querying Capabilities
Data Displays (Presentation)
Data entry
Data Validation
Data Deletion
Committing Procedures (of changes)
AND Data Integrity, Security, Consistency and Concurrency
Capabilities
CSE3180 Semester 1,2005. Lect 1 / 30
The Many Faces of Database
• 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)
CSE3180 Semester 1,2005. Lect 1 / 31
The Many Faces of Database
Hardware
Database
Raw Data
Total Disk
HP9000
Oracle
100GB
643GB
Digital 8400
Oracle
100GB
361GB
IBM SP2
DB2/6000
100GB
377GB
NCR5100
Teradata
100GB
880GB
NCR5100
Teradata
1,000GB
3,280GB
CSE3180 Semester 1,2005. Lect 1 / 32
Important Database Features
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•
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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
CSE3180 Semester 1,2005. Lect 1 / 33
Data Base Models - Hierarchical
owner / parent
owner
child / parent
member
child
child / parent
CSE3180 Semester 1,2005. Lect 1 / 34
Data Base Models - Network
set of
data
owner
member
owner
member
set of data
Note: Only linked sets can be accessed
CSE3180 Semester 1,2005. Lect 1 / 35
Data Base Models - Network
set of
data
owner
member
set of data
Note: Only linked sets can be accessed
CSE3180 Semester 1,2005. Lect 1 / 36
Data Base Models - Relational
table
A
table
B
table
C
table
D
table
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
CSE3180 Semester 1,2005. Lect 1 / 37
A quick introduction to the developer of
the Relational Data Base
The late Dr. E. Codd
CSE3180 Semester 1,2005. Lect 1 / 38
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.
CSE3180 Semester 1,2005. Lect 1 / 39
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.
CSE3180 Semester 1,2005. Lect 1 / 40
2 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
314
Relation (Table) Name : EMP
Relation Schema: EMP(empnum,name,date of birth,deptnum)
DEPTNUM
201
314
432
605
DEPTNAME
Production
Finance
Information Systems
Administration
Relation (Table) Name : DEPT
Relation Schema: DEPT(deptnum, deptname)
Referenced
Table
CSE3180 Semester 1,2005. Lect 1 / 41
What are these ?
EMP
DEPT
They are the
Entities
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
CSE3180 Semester 1,2005. Lect 1 / 42
Relational 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
CSE3180 Semester 1,2005. Lect 1 / 43
Some RDB Considerations
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•
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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
CSE3180 Semester 1,2005. Lect 1 / 44
Some 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
CSE3180 Semester 1,2005. Lect 1 / 45
Database 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)
CSE3180 Semester 1,2005. Lect 1 / 46
Data 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
CSE3180 Semester 1,2005. Lect 1 / 47
Data 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
CSE3180 Semester 1,2005. Lect 1 / 48
A Typical Database Model
Users - keyboard direct
User
s
Menu
Options
Programs written in
Cobol, C, C++, Pascal
Java etc.
P
r
o
g
r
a
m
I
n
t
e
r
f
a
c
e
D
B
M
S
Database
Database Query
Access Language
CSE3180 Semester 1,2005. Lect 1 / 49
Advantages of Database
• Reduced Data Redundancy
• Data Integrity
• Data Independence
• Data Security
• Data Consistency
• Easier use of Data via DBMS Tools (Query languages,
4GL's)
CSE3180 Semester 1,2005. Lect 1 / 50
Disadvantages of Database
• Complexity
• Expense
• Vulnerability
• Size of - disk storage, processor memory
• Training Costs
• Compatibility
• Technology Lock In
CSE3180 Semester 1,2005. Lect 1 / 51
More 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)
CSE3180 Semester 1,2005. Lect 1 / 52
More 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
CSE3180 Semester 1,2005. Lect 1 / 53
Overview of DataBase
Data Creation
Subject to
DataBase
Reliability, Content,
Completeness
Good Data
Input to
Database Tables
SCM
BPM
CRM
…..
:
Audit
Time Relevance
Advanced Business Rules
New DBMS
New Applications
Altered Business Rules
Associated with other
Business Applications
Users
People, Other Systems
Web based Access
CSE3180 Semester 1,2005. Lect 1 / 54
Overview of DataBase
Legacy Data
from Legacy Systems
Current
DataBases
DataWarehousing Processes
Data Mining
Business Based Performance Analyses
CSE3180 Semester 1,2005. Lect 1 / 55
Your 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
CSE3180 Semester 1,2005. Lect 1 / 56
CSE3180 Semester 1,2005. Lect 1 / 57
The 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.
CSE3180 Semester 1,2005. Lect 1 / 58
The 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.
CSE3180 Semester 1,2005. Lect 1 / 59
Your Assignment
• 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
CSE3180 Semester 1,2005. Lect 1 / 60
Your Assignment
• 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
CSE3180 Semester 1,2005. Lect 1 / 61
Your Assignment
• 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.
CSE3180 Semester 1,2005. Lect 1 / 62
Your Assignment
• 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
CSE3180 Semester 1,2005. Lect 1 / 63
Part 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
CSE3180 Semester 1,2005.
Lect 1 / 64
Your Assignment
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)
CSE3180 Semester 1,2005. Lect 1 / 65
Your Assignment - Part 2
For Part 2 you will need to develop :
– Data structures
– Constraints
– Test strategy
– Test data
– Testing results
– Operational model
CSE3180 Semester 1,2005. Lect 1 / 66
Your 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
CSE3180 Semester 1,2005. Lect 1 / 67
Your Assignment
• 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
CSE3180 Semester 1,2005. Lect 1 / 68
Your Assignment
• 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
CSE3180 Semester 1,2005. Lect 1 / 69
Your Assignment
• 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
CSE3180 Semester 1,2005. Lect 1 / 70
Building 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
CSE3180 Semester 1,2005. Lect 1 / 71
The 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 examination will be held on Friday 10th December from
1.30pm to 3.45pm
CSE3180 Semester 1,2005. Lect 1 / 72
That should be enough for today
The website :
http://www.csse.monash.edu.au/courseware/cse3180s
and make sure you reference cse3180s
CSE3180 Semester 1,2005. Lect 1 / 73