IMS1907 Database Systems

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IMS1907 Database Systems

• Summer Semester 2004/2005
• Lecture 1
• Introduction to Database Systems
• Fundamentals and Concepts

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People

• Lecturer
• David Grant
• Phone [phone]
• david.grant_at_infotech.monash.edu.au
• Tutors
• Reagan Low
• Arvind Arcot

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Resources

• www.sims.monash.edu.au/subjects/IMS1907/index.html
  
• www.sims.monash.edu.au/resources/assessment.html
• Required text book
• Hoffer, J.A., Prescott, M.B. and McFadden, F.R.,
  (2002), (7th edn.), Modern Database Management,
  Pearson Education Inc., Upper Saddle River, NJ,
  USA.

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Unit Structure

• 1 x 2 hour lecture per day for 13 days
• 1 x 2 hour laboratory/tutorial per day
• tutorial exercises
• unit test preparation
• Two unit tests together worth 20 each
• Microsoft Access, SQL
• One final examination, 3 hours, worth 60

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Inescapable Truths

• Lecturers do not really teach you anything, they
  present you with toolkits and information
• The overheads are a guide to points of discussion
  - they do not contain the total wisdom on any
  given topic
• They identify and discuss the topics and issues
  you need to consider and understand when using
  the tools
• You learn by your own efforts at reading,
  comprehending, discussing and doing this is a
  technical subject!
• Your assessed outcomes, generally, are directly
  proportional to your effort - you make yourself
  more equal!

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Database Systems Topics

• Introduction. database fundamentals and concepts
• Data modelling
• Relational theory
• Normalisation
• SQL
• Database systems development
• Database design and optimisation
• Data warehouses, OODBMS, internet DBs
• Database systems and organisations - roles of DA,
  DBA

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What are Database Systems?

• Many different types of information systems
• TPS, GIS, MIS, DSS, EIS, KBS, expert, messaging,
  HRIS, SIS, enterprise..
• used IS in many business areas to perform many
  functions
• banking, airlines, universities, credit cards,
  finance, telecommunications, sales,
  manufacturing, HR
• Almost all of these rely on a database in some
  way
• In fact, database systems are at the heart of
  most information systems

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Impact of Database Systems

• The amount of information being collected and
  stored is almost beyond comprehension and its
  growing
• Stored information is being used for more
  purposes than were conceivable ten (or even five)
  years ago
• Databases are used at every level of society
• individuals, small business, national
  organisations, global corporations, governments
• They affect many aspects of our everyday lives

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Impact of Database Systems

• Databases are used in
• monitoring and improving business operations
• tracking customers and their behaviour
• tracking and despatching emergency service
  vehicles
• monitoring communications with space vehicles
• making decisions (business and otherwise)
• generating spam
• performing surgical procedures
• many other applications from the mundane to
  miraculous

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Impact of Database Systems

• Critical to business productivity and
  profitability
• Critical to individual life and safety
• Instrumental in economic and social stability
• Can affect governments
• It essential that information is accurate,
  up-to-date and consistent
• Not always easy when there are so many databases
  of so many types storing different versions of
  similar or the same information

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A Brief History of Database Systems
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A Brief History of Database Systems
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Basic Concepts

• Central concepts for understanding database
  systems
• Database
• Data
• Information
• Data vs Information
• Metadata
• DBMS

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Database

• An organised collection of logically related data
• Has some inherent meaning
• Represents some aspect of the real world (UoD)
• Vary in size and complexity (MB ? TB)
• Designed, built, and populated with data for a
  specific purpose and for intended users
• Generated and maintained manually or computerised

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Data

• Traditionally referred to facts about things and
  events that could be recorded and stored (on
  computer media)
• Referred to as structured data
• Data types are numeric, characters, dates
• Stored as records in files (older) or more
  commonly in tabular form (tables, relations,
  arrays, spreadsheets, etc)

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Data

• Traditional definition does not reflect current
  reality
• structured data is the not the only type stored
• Documents, images, sound, video
• Unstructured data or multimedia data
• stored representations of objects and events
  that have meaning and importance in the users
  environment.
• Multimedia environments store and display
  structured and unstructured data

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Data vs Information

• The terms data and information are often used
  interchangeably but it is useful to distinguish
  between them
• Information
• data that have been processed in such a way
  that the knowledge of the person who uses the
  data is increased.
• data with a context and other associated useful
  data
• often summarised or otherwise-processed data that
  is presented for interpretation

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Metadata

• data that describe the properties or
  characteristics of end user data and the context
  of that data.
• Data names, definitions, length/size, allowable
  values
• Data source, storage location, stewardship, usage
• Data about data once removed from the data
• Enables users and designers to understand what
  data exists, what it means avoid errors,
  misinterpretation
• Stored in the system catalog

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Database Management System (DBMS)

• a software system that is used to create,
  maintain, and provide controlled access to user
  databases.
• A general purpose set of software tools that
  facilitates the process of defining, constructing
  and manipulating data in a database for some
  specific purpose in a known context
• Provides systematic method for creating,
  updating, storing and retrieving data in a
  database

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Database Management System (DBMS)

• Data sharing between end users and programmers
• Data sharing across multiple applications
• Data access control, data integrity enforcement,
  concurrency control, restoration
• MS Access, MS SQL Server, Oracle, MySQL,
  Informix, DB2, Teradata, Ingres, SyBase
• Objectivity, Cache, Gemstone, Jasmine, O2,
  ObjectStore, POET, Versant

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DBMS vs File Processing Systems

• Traditional File Processing systems had
  disadvantages
• program-data dependence
• data duplication, inconsistency
• integrity problems
• hard to access
• atomicity, concurrency, security problems
• limited data sharing
• lengthy development times
• excessive program maintenance

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DBMS vs File Processing Systems

• DBMS provide benefits when compared to
  traditional File Processing systems
• program-data independence
• minimal data redundancy - controlled
• improved data consistency
• improved data sharing
• improved access and security controls
• increased productivity of application development

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DBMS vs File Processing Systems

• DBMS benefits
• enforcement of standards
• improved data quality
• improved data accessibility and responsiveness
• reduced program maintenance
• improved decision support
• persistent storage for application objects and
  data structures

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DBMS vs File Processing Systems

• DBMS benefits
• rule-based inferencing and actions
• multiple user interfaces
• multi-user transaction processing
• represent complex data relationships
• enforce integrity constraints
• backup and recovery

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What are Database Systems?

• A database system contains
• DBMS
• database
• metadata (repository)
• Also in the database system environment are
• application software
• CASE tools
• user interfaces
• users, developers, administrators

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Database Systems
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Database Systems
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Types of Database Systems

• Personal Databases
• Workgroup Databases
• Department Databases
• Enterprise Databases
• Internet, Intranet, and Extranet Databases
• Data warehouses

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Costs and Risks of Database Systems

• Need for new, specialised personnel
• Installation cost and complexity
• Maintenance cost and complexity
• Conversion costs from legacy systems
• Critical need for explicit backup and recovery
• Organisational conflict and change

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Database Systems and Organisations

• An organisations success or failure can depend
  on the accuracy and availability of its
  information
• An expensive pause (source Standish Group)

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Database Systems and You

• What databases have you been in contact with this
  week? (directly and indirectly)
• What databases are you on that you know about?
• What databases do you think you might be on that
  you dont know about?
• How important is it that you are on at least some
  databases?

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Reading for Next Week

• Hoffer et al, Chapter 2

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References

• Elmasri, R. and Navathe, S.B., (2000), (3rd
  edn.), Fundamentals of Database Systems,
  Addison-Wesley, Reading, Massachusetts, USA.
• Hoffer, J.A., Prescott, M.B. and McFadden, F.R.,
  (2002), (7th edn.), Modern Database Management,
  Pearson Education Inc., Upper Saddle River, NJ,
  USA.
• Murphy, B., (1999), Data Downtime Dilemma,
  accessed 5th July 2004 at http//www.findarticles.
  com/p/articles/mi_m0SMG/is_3_19/ai_59329322.