Re: Self-join

From: Andrus Adamchik (andru..bjectstyle.org)
Date: Wed Jun 27 2007 - 09:58:33 EDT

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    Or actually ... I take it back :-)

    The underlying cause is still the inability to build correct joins
    when traversing a multi-step path qualifier, such as "parent.parent =
    null". This explains why Mike's patch made a difference.

    Andrus

    On Jun 27, 2007, at 4:50 PM, Andrus Adamchik wrote:

    > Just to clarify, CAY-732 is a real bug, but it is not a bug with
    > relationships to same entity per se (those resolve just fine). This
    > is a bug specifically related to *prefetching* on such relationships.
    >
    > Andrus
    >
    >
    > On Jun 12, 2007, at 10:33 PM, Mike Kienenberger wrote:
    >
    >> Not really sure as I don't use them, but at least one issue with
    >> self-joins is solved if you use my outer join patch for 1.2.
    >>
    >> https://issues.apache.org/cayenne/browse/CAY-732
    >>
    >>
    >>
    >> On 6/12/07, Fredrik Liden <flide..ranslate.com> wrote:
    >>> What is the status of self joins in v. 1.2.3?
    >>> From the 2 posts I find in the archive seems like some people are
    >>> using
    >>> it.
    >>> The documentation doesn't mention it.
    >>> Just wondering if it's ok to use or if there are any limitations
    >>> that
    >>> discourages it's use?
    >>>
    >>> I'm have a set of nodes. I'm guessing the source node will have
    >>> Source_node_id NULL or 0. And then the target nodes will refer
    >>> back to
    >>> the source nodes Node_id. Would it be worth using self joins here or
    >>> should I just look up the target nodes based on the source nodes
    >>> using
    >>> regular queries and not worry about the relations?
    >>>
    >>> NODE
    >>>
    >>> Node_id (pk)
    >>> Text
    >>> Source_node_id (fk)
    >>>
    >>> Thanks!
    >>> Fredrik
    >>>
    >>
    >
    >



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