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Implement allow_migrate for migration operations

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Andrew Godwin 2013-07-30 12:34:31 +01:00
parent 12e9804d16
commit fddc5957c5
6 changed files with 156 additions and 44 deletions
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10
docs/topics/db/multi-db.txt
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@ -163,8 +163,14 @@ A database Router is a class that provides up to four methods:
the router has no opinion. This method can be used to determine
the availability of a model on a given database.
Note that if this returns ``True`` for an app with migrations but
``False`` for an app those migrations depend on, Django will error.
Note that migrations will just silently not perform any operations
on a model for which this returns ``False``. This may result in broken
ForeignKeys, extra tables or missing tables if you change it once you
have applied some migrations.
The value passed for ``model`` may be a
:ref:`historical model <historical-models>`, and thus not have any
custom attributes, methods or managers. You should only rely on ``_meta``.
A router doesn't have to provide *all* these methods -- it may omit one
or more of them. If one of the methods is omitted, Django will skip