[Dbix-class] Self join for hierarchy

Bill Moseley moseley at hank.org
Wed Aug 21 20:52:31 GMT 2013

I have a table with a self-referencing parent column.  The depth of any
hierarchy is limited so I can write a join to fetch all the parents.

For example, if the table folder has a parent column:

    p0.id as parent0,
    p1.id as parent1,
    p2.id as parent2
    folder f
    left join folder p0 on p0.id =3D f.parent
    left join folder p1 on p1.id =3D p0.parent
    left join folder p2 on p2.id =3D p1.parent
    f.id =3D ?

I know I can specify a join multiple times

    join =3D> [ 'parent', 'parent', 'parent' ]

and DBIC will create separate aliases but they all join to the same "base"
table.   But, I need to join like above.

Is there a way to specify these joins or do I need to use a virtual view?

-- =

Bill Moseley
moseley at hank.org
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