Revision 1c11bace snf-cyclades-app/synnefo/db/managers.py
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""" |
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def __init__(self, *args, **kwargs): |
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super(ForUpdateManager, self).__init__(*args, **kwargs) |
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self._select_for_update = False |
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def select_for_update(self, *args, **kwargs): |
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return ForUpdateQuerySet(self.model, using=self.db) |
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class ForUpdateQuerySet(QuerySet): |
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""" QuerySet implmenting SELECT .. FOR UPDATE statement |
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This QuerySet overrides filter and get methods in order to implement |
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select_for_update() statement, by appending 'FOR UPDATE' to the end |
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for the SQL query. |
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""" |
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def filter(self, *args, **kwargs): |
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query = self.get_query_set().filter(*args, **kwargs) |
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if self._select_for_update: |
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self._select_for_update = False |
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return for_update(query) |
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else: |
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return query |
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query = super(ForUpdateQuerySet, self).filter(*args, **kwargs) |
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return for_update(query) |
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def get(self, *args, **kwargs): |
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if not self._select_for_update: |
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return self.get_query_set().get(*args, **kwargs) |
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query = self.filter(*args, **kwargs) |
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query = list(query) |
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num = len(query) |
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"Lookup parameters were %s" % |
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(self.model._meta.object_name, num, kwargs)) |
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def select_for_update(self, *args, **kwargs): |
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self._select_for_update = True |
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return self |
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def for_update(query): |
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""" Rewrite query using SELECT .. FOR UPDATE. |
Also available in: Unified diff