Re: [CONF] Apache Cayenne Documentation: Inheritance overview (page created)

From: Aristedes Maniatis (ar..aniatis.org)
Date: Thu May 31 2007 - 19:37:41 EDT

  • Next message: Aristedes Maniatis: "vertical inheritance joins [Was: Abstract Entities]"

    On 01/06/2007, at 2:26 AM, Mike Kienenberger wrote:

    > You might want to grab some of the info on
    >
    > http://cwiki.apache.org/confluence/display/CAY/Is+Inheritance
    > +Supported
    >
    > and merge it into your new document.
    >
    > I'm thinking specifically about the additional names by which
    > vertical, horizontal, and single inheritance are known by. This
    > makes it easier for folks coming in from an ORM where the terminology
    > is different.

    Is that terminology right? That page says:

    * single-table == flat == table-per-class-hierarchy
    * Vertical == table-per-subclass
    * Horizontal == table-per-concrete-class

    My page says:

    * single-table
    * horizontal == table-per-class
    * vertical == joined

    I don't see how table-per-class can be used to describe single-table
    inheritance, since there isn't a table per class. Just one table. And
    vertical isn't table per subclass, it also has another table.
    Finally, there is no reason the horizontal superclass can't be concrete.

    If anything, horizontal should be described as 'table-per-subclass'.

    The terminology is very important I agree, but do you have any
    references for those terms, so that we can use the what people will
    be expecting to see? The main references we've been looking at are
    the JPA docs, Hibernate and WO docs.

    Cheers
    Ari

    -------------------------->
    Aristedes Maniatis
    phone +61 2 9660 9700
    PGP fingerprint 08 57 20 4B 80 69 59 E2 A9 BF 2D 48 C2 20 0C C8





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