Re: Mixing OO and DB

ram_at_zedat.fu-berlin.de (Stefan Ram) writes:
>shirt.makeSelfClean()

  Or,

shirt.wash()

  . This is a noun (»shirt«) and a verb (»wash«).

  Could one imagine a world where natural language linguistics   become so prevalent in user interfaces (because they are so   natural) that one day computers have a »verb« and a »noun« key?

  This is the keyboard from the Apollo computer panel of 1969:

http://infolab.stanford.edu/pub/voy/museum/pictures/display/0-2-ApolloPanel.jpg

  Commands looked like

      »V21 N27E 10E«

http://www.ibiblio.org/apollo/

  But is this object-oriented at all?

  After all, a classical command like

cat tmp.txt

  also has a verb and a noun.

  Object-orientation starts when a single verb can be   used metaphorically for multiple types of nouns and   still has the same meaning (as a metaphor).

  So,

textedit tmp.txt
picedit  tmp.pic
binedit  tmp.bin

  is not object-oriented, while

edit tmp.txt
edit tmp.pic
edit tmp,bin

  is object-oriented if »edit« selects the appropriate editor by   the file type and can be extended to new types without the   need to modify existing code.

  So, object-orientation

    0 - decouples verbs from noun types for metaphoric use, and

    1 - splits verb source code units into separate units

        for each noun type, so that they can be changed
        independently.

  In SQL, there is something similar: One can apply the verb   »SELECT« to any table, whether it is a base table or a view,   even if the implementation of these two selections differs.

  But this is only »object-based«, as it is sometimes called,   because it fulfills only »0« (in some case). It can not   fulfill »1«, because one can not extend verbs in SQL.   (One can define views, but this are more like nouns.)

  But one can imagine an object-oriented language in a database   system, where base tables and views are objects and verbs can   be defined for those. A relation can be regarded as the type   of its elements (rows).

  An object-oriented database operation:

      for each customer c do sendPresentTo( c );

  , where »customer« is a table containing customers of   different types (men, women, and children) and »sendPresent«   has a different implementation for each type of customer. Received on Wed Feb 13 2008 - 21:26:49 CET