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 "Theoretical" Topics in Database Courses?

  • 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 "Theoretical" Topics in Database Courses?

  • 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 "Theoretical" Topics in Database Courses?

  • 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 "Theoretical" Topics in Database Courses?

  • 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 "Theoretical" Topics in Database Courses?

  • 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 "Theoretical" Topics in Database Courses?

  • 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 "Theoretical" Topics in Database Courses?

  • 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 "Theoretical" Topics in Database Courses?

  • 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 "Theoretical" Topics in Database Courses?

  • Heritage and Alternatives in Databases

  • Past and Present

  • Issues and Experiences

Ivanjica, 6 – 10. 9. 2010.


Past and present
Past and "Theoretical" Topics in Database Courses?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 "Theoretical" Topics in Database Courses?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 "Theoretical" Topics in Database Courses?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 "Theoretical" Topics in Database Courses?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 "Theoretical" Topics in Database Courses?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 "Theoretical" Topics in Database Courses?

  • Heritage and Alternatives in Databases

  • Past and Current State

  • Issues and Experiences

Ivanjica, 6 – 10. 9. 2010.


Issues and experiences
Issues and Experiences "Theoretical" Topics in Database Courses?

  • 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 "Theoretical" Topics in Database Courses?

  • 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 "Theoretical" Topics in Database Courses?

  • 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 "Theoretical" Topics in Database Courses?

  • 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 "Theoretical" Topics in Database Courses?

  • 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 "Theoretical" Topics in Database Courses?

  • 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 "Theoretical" Topics in Database Courses?

  • 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 "Theoretical" Topics in Database Courses?

  • 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 "Theoretical" Topics in Database Courses?

  • 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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