face off should we teach synthesis algorithm and related theoretical topics in database courses
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Face-off: Should we teach Synthesis Algorithm and Related "Theoretical" Topics in Database Courses?. Agenda. Heritage and Alternatives in Databases Past and Present Issues and Experiences. Heritage and Alternatives in Databases. A brief history of data models

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face off should we teach synthesis algorithm and related theoretical topics in database courses

Face-off: Should we teach Synthesis Algorithm and Related "Theoretical" Topics in Database Courses?

Ivanjica, 6 – 10. 9. 2010.

agenda
Agenda
  • Heritage and Alternatives in Databases
  • Past and Present
  • Issues and Experiences

Ivanjica, 6 – 10. 9. 2010.

heritage and alternatives in databases
Heritage and Alternatives in Databases
  • A brief history of data models
    • Many data models and paradigms in database (db) design during the last four decades
    • Implementation data models
      • provided by commercial DBMSs
    • Conceptual data models
      • mostly used in the db design process
      • to create conceptual db schema specifications
      • that may be characterized as platform independent (PIM)
    • Still "theoretical" data models
      • provided by some DBMSs
      • designated as very "new" and "promising", but
      • a number of their commercial applications in industry practice is still rather small

Ivanjica, 6 – 10. 9. 2010.

heritage and alternatives in databases1
Heritage and Alternatives in Databases
  • A brief history of data models
    • Implementation data models
      • the most favorable is still Relational Data Model (RDM)
        • a long tradition and considerable popularity
        • very extensive commercial usage and broad application
        • we may believe that it will continue
          • thanking to its sound theoretical, i.e. mathematical background
        • many logical problems, their solutions, and principles concerning db design are formally defined at the level of RDM
    • Conceptual data models
      • the most favorable is still Entity-Relationship (ER) data model
        • also a long tradition

Ivanjica, 6 – 10. 9. 2010.

heritage and alternatives in databases2
Heritage and Alternatives in Databases
  • Design approaches
    • A typical scenario of db schema design process
      • (1) create the first an ER database schema and then
      • (2) transform it into the relational database schema
    • Many advantages
    • A number of CASE tools providing such transformation process
    • It is based on applying well-known mapping rules
      • with a common belief that such rules will guarantee the satisfaction of the Third Normal Form condition (3NF) per se

Ivanjica, 6 – 10. 9. 2010.

heritage and alternatives in databases3
Heritage and Alternatives in Databases
  • Design approaches
    • A typical scenario of db schema design process
      • (1) create the first an ER database schema and then
      • (2) transform it into the relational database schema
    • Unfortunately, a reality is different
      • many obstacles or pitfalls may appear on that road
    • Serious disadvantages - lack of semantic problem
      • some mapping rules may be characterized only as advisable
      • the transformation process depends not only on the formal mapping rules, but also on the problem domain semantics
      • many examples in which the same structure of ER db schema should not be transformed into the same relational db schema structure
        • due to the different semantics assigned to the ER structure

Ivanjica, 6 – 10. 9. 2010.

heritage and alternatives in databases4
Heritage and Alternatives in Databases
  • Design approaches
    • A typical scenario of db schema design process
      • (1) create the first an ER database schema and then
      • (2) transform it into the relational database schema
    • Main consequences
      • a designer is forced to make some further corrections of a relational db schema
        • obtained by the transformation algorithm
      • the source and target db schemas become unsynchronized
      • the quality of such designed db schemas is highly dependant of designers'
        • theoretical knowledge and previous experience
        • perception power and ability to recognize an influence of the problem domain semantics onto the transformation process

Ivanjica, 6 – 10. 9. 2010.

heritage and alternatives in databases5
Heritage and Alternatives in Databases
  • Design approaches
    • Many principles concerning db design are formally defined at the level of RDM, but unfortunately
    • Only some of them are widely exploited in practice
    • An alternative approach
      • db schema design based on well-known synthesis algorithm
        • originally defined by [Beeri C., Bernstein P.A.; 1979]
      • provides a powerful formalization of the relational db schema design process, but
      • suffers from a number of problems blocking its practical usage
        • still rarely exploited in practice

Ivanjica, 6 – 10. 9. 2010.

heritage and alternatives in databases6
Heritage and Alternatives in Databases
  • Our research results provide
    • Raising the synthesis algorithm to the level of its practical application
      • in large db design projects
      • in the scope of Model Driven Software Development (MDSD) process
    • Overcoming the problems of db schema design based on ER data model and transformations into RDM
      • we have made necessary improvements of the synthesis algorithm and
      • embedded it into our MDSD tool, named IIS*Case
        • presented two years ago

Ivanjica, 6 – 10. 9. 2010.

agenda1
Agenda
  • Heritage and Alternatives in Databases
  • Past and Present
  • Issues and Experiences

Ivanjica, 6 – 10. 9. 2010.

past and present
Past and Present
  • Academy World
    • Past (app. two decades before)
      • theoretical and formal foundations of databases used to teach in detail
        • with considerably less problems felt by teachers
      • students did not complain much about it
        • they were to learn it, and they learned it

Ivanjica, 6 – 10. 9. 2010.

past and present1
Past and Present
  • Academy World
    • Current state
      • faculties are fighting for students
        • surviving formula for both state and private faculties is
        • STUDENTS + LESSONS = MONEY
      • deans are frightened of loosing students
      • a majority of students are frightened of theory, mathematical formalisms, and reading books in general
        • they believe that Internet is the only source they are supposed to consult for everything in their life
          • just a brief look at Wikipedia, Facebook / forums and Google Services is enough for everything
        • they are always complaining about theory and "deep" formalisms, by default
      • as a result, significantly reduced level of theoretical knowledge is transferred to students, in average

Ivanjica, 6 – 10. 9. 2010.

past and present2
Past and Present
  • Research World
    • Past (app. two or three decades before)
      • theoretical and formal foundations of relational databases used to develop intensively
      • many logical problems in db design were resolved at the level of RDM
        • a heritage that must be tailored in any new data model being developed
      • in late 90's, theoretical and formal approaches in databases were almost forgotten
        • they were not "fashionable" enough for hot research
    • Current state
      • coming back to the roots, through XML data model
        • the same fundamental principles and ideas evolved
      • employing MDSD and DSL approaches is promising

Ivanjica, 6 – 10. 9. 2010.

past and present3
Past and Present
  • Software Industry World
    • Past (app. two or three decades before)
      • a considerable number of large and medium-size companies
        • from various industry and government sectors
        • having their own informatics departments
        • with the main goal not only to support the maintenance of a company IS, but to really perform its development
        • large software development centers
          • employed predominantly high (academic) educated people
      • invested a lot of money in various training programs
        • to raise the level of technological, as well as the methodological knowledge necessary for IS development
      • at the same time, a lot of rather small software companies
        • specialized for IS development and outsourcing software services

Ivanjica, 6 – 10. 9. 2010.

past and present4
Past and Present
  • Software Industry World
    • Current state
      • large and medium-size companies from various business sectors mostly become just buyers of software systems
        • many functions of the former informatics departments have been outsourced
          • reducing their responsibilities only to a minimum of maintenance
          • reducing the number and education profile of the staff
      • sellers are predominantly large software companies
        • offering their general purpose software systems that
          • may be localized, parameterized or customized
          • are usually independent of any particular DBMS

Ivanjica, 6 – 10. 9. 2010.

agenda2
Agenda
  • Heritage and Alternatives in Databases
  • Past and Current State
  • Issues and Experiences

Ivanjica, 6 – 10. 9. 2010.

issues and experiences
Issues and Experiences
  • Deans' messages
    • Please, slow down with your theory and database schemas, otherwise I will run out of all my students!
    • You should realize that today's students are not the same as you were!
    • How do you imagine to earn your salary without students?
    • Of course, theory is very important. You should preserve the quality of lecturing process for sure, but be careful to provide a high ratio of passed students!
    • Take an elective course and do there whatever you want, but don't touch in basic, mandatory courses!

Ivanjica, 6 – 10. 9. 2010.

issues and experiences1
Issues and Experiences
  • Students' messages
    • Positive:
      • Theory is really valuable to recognize all important issues in databases.
    • Pragmatic, funny, or possibly negative?
      • Who even cares about theory in database design process? It is completely unnecessary.
      • Please, teach us only the practice. We need just a practice.
      • We are always doing design in an intuitive and practical way.
      • I know the process very well. Just simply draw up some tables and link them by foreign keys. It is really easy, isn't it?

Ivanjica, 6 – 10. 9. 2010.

issues and experiences2
Issues and Experiences
  • Colleagues' messages
    • Average students fill great troubles in adopting the theory and mathematical formalisms of RDM
      • just like formalisms in other areas, such as languages and compilers
    • They even couldn't perceive the synthesis algorithm, at all
    • A common advise: remove the synthesis algorithm and "high" theory from the database courses
      • this is reported by many colleagues from various universities
    • Alternatively, you may include such topics in the elective advanced courses, but with a special care!

Ivanjica, 6 – 10. 9. 2010.

issues and experiences3
Issues and Experiences
  • Messages from software sellers
    • Suggestive, and usually accepted without any serious analysis in a today's high-speed life
      • What company is to develop its own database and IS? It is time consuming and does not pay off, at all!
      • Just buy our solution. It will resolve all your problems in the best way and it is the cheapest solution for you!
        • Many satisfied customers of our solution testify that for many years.
      • If you buy our solution, you may choose any DBMS you like. You will not be dependant of any DBMS provider.
      • We can efficiently and easily customize a solution for you to ideally fit to your business!

Ivanjica, 6 – 10. 9. 2010.

issues and experiences4
Issues and Experiences
  • Main issues
    • Unfortunately, unforeseen and not seriously perceived side effects and expenses
    • DBMS independence:
      • database schema will contain only tables, columns, primary keys, and probably simple foreign key constraints
        • nothing more than that
        • a power of DBMS is exploited in a really small extent
      • everything else is an enormously complex middle-layer business logic deployed at application servers
        • latter on, a customer has to pay a great amount of money for its maintenance and trivial customizations, just to that seller

Ivanjica, 6 – 10. 9. 2010.

issues and experiences5
Issues and Experiences
  • Main issues
    • Unfortunately, unforeseen and not seriously perceived side effects and expenses
    • "Easy" customizations may result in:
      • careless adding a mass of new tables and columns
      • poorly controlled, chaotic and erroneous database solutions
    • However, all these messages are fully pragmatic!
    • Even, there is a new message from all sides:
      • We are aware of future potential problems, but let us resolve our urgent problems, ASAP!
      • And finally, who cares about the far future.

Ivanjica, 6 – 10. 9. 2010.

issues and experiences6
Issues and Experiences
  • Academic experiences from FTS
    • currently, two courses
      • Databases, 4+3, VII semester, mandatory for all CS students
        • about 80 students per year
        •  20% 9's and 10's on the scale of grades 5-10
        • includes theory and formalisms (RDM, relational algebra, functional dependencies and normal forms)
      • Database Systems, 3+3, VIII semester, elective
        • No. of students:
          • 7 in the first running year, 42,8% of 10's
          • 22 in the second running year, 41% of 10's
        • includes the synthesis algorithm and related "heavy" formalisms, but
        • also includes a GUI tool that provide its practical application in database design process

Ivanjica, 6 – 10. 9. 2010.

issues and experiences7
Issues and Experiences
  • Academic experiences from FTS
    • from this academic year, three courses
      • Databases I, 4+4, V semester, mandatory for all CS & CE students
        • about 140 students per year
        • basic theory and formalisms
      • Databases II, 2+2, VII semester, mandatory for all CS students
        • about 80 students per year
        • moderate theory and formalisms
      • Database Systems, 3+3, VIII semester, elective
        • No. of students:
          • we may expect 20 students per year
        • strong theory and formalisms, but also
        • balance between theory and practice

Ivanjica, 6 – 10. 9. 2010.

issues and experiences8
Issues and Experiences
  • We believe that
    • a respectable academic education system
      • preserving the balance between theory and practice
    • combined with customized training programs
    • a utilization of theoretical foundations combined with MDSD and DSL approaches
      • throughout the whole database development process

has a considerable potential to do much more for software industry than it really does today

  • Who is responsible for the far future and strategy decisions?

Ivanjica, 6 – 10. 9. 2010.

face off should we teach synthesis algorithm and related theoretical topics in database courses1

Face-off: Should we teach Synthesis Algorithm and Related "Theoretical" Topics in Database Courses?

End of presentation

Ivanjica, 6 – 10. 9. 2010.

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