#3592: Allowing Q Objects to select between OUTER and INNER joins (semi-
intelligently)
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Reporter: [EMAIL PROTECTED] | Owner: adrian
Status: new | Component: Database wrapper
Version: SVN | Resolution:
Keywords: Q,QuerySet,JOINs | Stage: Design decision needed
Has_patch: 1 | Needs_docs: 0
Needs_tests: 1 | Needs_better_patch: 1
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Changes (by [EMAIL PROTECTED]):
* needs_better_patch: 0 => 1
Comment:
Some more things:
I realized that the ``correct way'' to do ORing is by use of UNION. For
example, if I have three models:
X, Y, and Z (each with parameters a,b,c) and both Y and Z foreign key to
X: Z --> X and Y --> X. Then:
(They are all in app `package')
Q(y__a__isnull = False) | Q(z__b__isnull = False) should yield the
following query:
(approximate)
SELECT * FROM package_x
INNER JOIN "package_y" AS "package_x__y" ON
package_x.id = package_x__y.x_id
WHERE package_x__y.a IS NOT NULL
UNION
SELECT * FROM package_x
INNER JOIN "package_z" AS "package_x__z" ON
package_x.id = package_x__z.x_id
WHERE package_x__z.b IS NOT NULL
Is this clear?
Unfortunately, it would take some rewriting of django to even attempt
this.
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Ticket URL: <http://code.djangoproject.com/ticket/3592#comment:3>
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