Re: Help: Hollow class

From: Steve Wells (stwell..wnmail.net)
Date: Mon Feb 02 2004 - 02:13:24 EST

  • Next message: Gentry, Michael: "RE: Help: Hollow class"

    Hey Andrus,

    Excellent that works. I guess I was still trying to link on the old
    natural-key columns instead of using generated ones...still getting my
    head around this concept. I would have actually thought I could "join"
    on any arbitrary columns?

    Is there a good reference somewhere explaining the benefits of generated
    vs meaningful/natural keys?

    Thanks for the speedy and very helpful response.

    Steve

    On Mon, 2 Feb 2004 01:27:46 -0500, "Andrus Adamchik"
    <andru..bjectstyle.org> said:
    > Hi Steve,
    >
    > Just from looking at your mapping, what I think confuses Cayenne (and
    > confuses me as well), is the fact that the relationship "whitelist ->
    > org" doesn't point to the primary key (id), but rather points to
    > another column (shortName). Any reason why you don't want to create
    > "whitelist.orgId" column that points to org.id?
    >
    > Thanks
    > Andrus
    >
    > On Feb 2, 2004, at 12:47 AM, Steve Wells wrote:
    >
    > > My datamodel is basically a 1 to many:
    > > Whitelist (a list of valid email suffixs for an Org) - The many side
    > > <db-entity name="whitelist" catalog="lgo">
    > > <db-attribute name="emailSuffix" type="VARCHAR" isMandatory="true"
    > > length="120"/>
    > > <db-attribute name="id" type="INTEGER" isPrimaryKey="true"
    > > isMandatory="true" length="11"/>
    > > <db-attribute name="orgName" type="VARCHAR" isMandatory="true"
    > > length="20"/>
    > > </db-entity>
    > >
    > > Org - An organisation - the one side
    > > <db-entity name="org" catalog="lgo">
    > > <db-attribute name="id" type="INTEGER" isPrimaryKey="true"
    > > isMandatory="true" length="11"/>
    > > <db-attribute name="shortName" type="VARCHAR" isMandatory="true"
    > > length="20"/>
    > > </db-entity>
    > >
    > > The relationships:
    > > <db-relationship name="toOrg" source="whitelist" target="org"
    > > toDependentPK="false" toMany="false">
    > > <db-attribute-pair source="orgName" target="shortName"/>
    > > </db-relationship>
    > > <db-relationship name="toWhitelist" source="org" target="whitelist"
    > > toDependentPK="false" toMany="true">
    > > <db-attribute-pair source="shortName" target="orgName"/>
    > > </db-relationship>
    > > <obj-relationship name="toOrg" source="Whitelist" target="Org"
    > > toMany="false">
    > > <db-relationship-ref source="whitelist" target="org" name="toOrg"/>
    > > </obj-relationship>
    > > <obj-relationship name="toWhitelist" source="Org" target="Whitelist"
    > > toMany="true">
    > > <db-relationship-ref source="org" target="whitelist"
    > > name="toWhitelist"/>
    > > </obj-relationship>
    > 

    -- 
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