Commit 0e93f60c authored by Malcolm Tredinnick's avatar Malcolm Tredinnick
Browse files

Fixed #10362 -- An update() that only affects a parent model no longer crashes. 

This includes a fairly large refactor of the update() query path (and
the initial portions of constructing the SQL for any query). The
previous code appears to have been only working more or less by accident
and was very fragile.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@9967 bcc190cf-cafb-0310-a4f2-bffc1f526a37
parent 14c8e522

django/db/models/sql/query.py

+67 −16
Original line number Diff line number Diff line
@@ -62,6 +62,7 @@ class BaseQuery(object): 
        self.dupe_avoidance = {}

        self.used_aliases = set()

        self.filter_is_sticky = False

        self.included_inherited_models = {}



        # SQL-related attributes

        self.select = []
@@ -171,6 +172,7 @@ class BaseQuery(object): 
        obj.default_cols = self.default_cols

        obj.default_ordering = self.default_ordering

        obj.standard_ordering = self.standard_ordering

        obj.included_inherited_models = self.included_inherited_models.copy()

        obj.ordering_aliases = []

        obj.select_fields = self.select_fields[:]

        obj.related_select_fields = self.related_select_fields[:]
@@ -304,6 +306,7 @@ class BaseQuery(object): 
            self.select = []

            self.default_cols = False

            self.extra_select = {}

            self.remove_inherited_models()



        query.clear_ordering(True)

        query.clear_limits()
@@ -458,6 +461,7 @@ class BaseQuery(object): 
        assert self.distinct == rhs.distinct, \

            "Cannot combine a unique query with a non-unique query."



        self.remove_inherited_models()

        # Work out how to relabel the rhs aliases, if necessary.

        change_map = {}

        used = set()
@@ -540,6 +544,9 @@ class BaseQuery(object): 
        """

        if not self.tables:

            self.join((None, self.model._meta.db_table, None, None))

        if (not self.select and self.default_cols and not

                self.included_inherited_models):

            self.setup_inherited_models()

        if self.select_related and not self.related_select_cols:

            self.fill_related_selections()
@@ -619,7 +626,9 @@ class BaseQuery(object): 
            start_alias=None, opts=None, as_pairs=False):

        """

        Computes the default columns for selecting every field in the base

        model.

        model. Will sometimes be called to pull in related models (e.g. via

        select_related), in which case "opts" and "start_alias" will be given

        to provide a starting point for the traversal.



        Returns a list of strings, quoted appropriately for use in SQL

        directly, as well as a set of aliases used in the select statement (if
@@ -629,22 +638,25 @@ class BaseQuery(object): 
        result = []

        if opts is None:

            opts = self.model._meta

        if start_alias:

            table_alias = start_alias

        else:

            table_alias = self.tables[0]

        root_pk = opts.pk.column

        seen = {None: table_alias}

        qn = self.quote_name_unless_alias

        qn2 = self.connection.ops.quote_name

        aliases = set()

        if start_alias:

            seen = {None: start_alias}

            root_pk = opts.pk.column

        for field, model in opts.get_fields_with_model():

            if start_alias:

                try:

                    alias = seen[model]

                except KeyError:

                alias = self.join((table_alias, model._meta.db_table,

                    alias = self.join((start_alias, model._meta.db_table,

                            root_pk, model._meta.pk.column))

                    seen[model] = alias

            else:

                # If we're starting from the base model of the queryset, the

                # aliases will have already been set up in pre_sql_setup(), so

                # we can save time here.

                alias = self.included_inherited_models[model]

            if as_pairs:

                result.append((alias, field.column))

                continue
@@ -996,6 +1008,9 @@ class BaseQuery(object): 
                if alias == old_alias:

                    self.tables[pos] = new_alias

                    break

        for key, alias in self.included_inherited_models.items():

            if alias in change_map:

                self.included_inherited_models[key] = change_map[alias]



        # 3. Update any joins that refer to the old alias.

        for alias, data in self.alias_map.iteritems():
@@ -1062,9 +1077,11 @@ class BaseQuery(object): 
            lhs.lhs_col = table.col



        If 'always_create' is True and 'reuse' is None, a new alias is always

        created, regardless of whether one already exists or not. Otherwise

        'reuse' must be a set and a new join is created unless one of the

        aliases in `reuse` can be used.

        created, regardless of whether one already exists or not. If

        'always_create' is True and 'reuse' is a set, an alias in 'reuse' that

        matches the connection will be returned, if possible.  If

        'always_create' is False, the first existing alias that matches the

        'connection' is returned, if any. Otherwise a new join is created.



        If 'exclusions' is specified, it is something satisfying the container

        protocol ("foo in exclusions" must work) and specifies a list of
@@ -1126,6 +1143,38 @@ class BaseQuery(object): 
        self.rev_join_map[alias] = t_ident

        return alias



    def setup_inherited_models(self):

        """

        If the model that is the basis for this QuerySet inherits other models,

        we need to ensure that those other models have their tables included in

        the query.



        We do this as a separate step so that subclasses know which

        tables are going to be active in the query, without needing to compute

        all the select columns (this method is called from pre_sql_setup(),

        whereas column determination is a later part, and side-effect, of

        as_sql()).

        """

        opts = self.model._meta

        root_pk = opts.pk.column

        root_alias = self.tables[0]

        seen = {None: root_alias}

        for field, model in opts.get_fields_with_model():

            if model not in seen:

                seen[model] = self.join((root_alias, model._meta.db_table,

                        root_pk, model._meta.pk.column))

        self.included_inherited_models = seen



    def remove_inherited_models(self):

        """

        Undoes the effects of setup_inherited_models(). Should be called

        whenever select columns (self.select) are set explicitly.

        """

        for key, alias in self.included_inherited_models.items():

            if key:

                self.unref_alias(alias)

        self.included_inherited_models = {}



    def fill_related_selections(self, opts=None, root_alias=None, cur_depth=1,

            used=None, requested=None, restricted=None, nullable=None,

            dupe_set=None, avoid_set=None):
@@ -1803,6 +1852,7 @@ class BaseQuery(object): 
            names.sort()

            raise FieldError("Cannot resolve keyword %r into field. "

                    "Choices are: %s" % (name, ", ".join(names)))

        self.remove_inherited_models()



    def add_ordering(self, *ordering):

        """
@@ -2004,6 +2054,7 @@ class BaseQuery(object): 
            select_alias = join_info[RHS_ALIAS]

            select_col = join_info[RHS_JOIN_COL]

        self.select = [(select_alias, select_col)]

        self.remove_inherited_models()



    def execute_sql(self, result_type=MULTI):

        """

django/db/models/sql/subqueries.py

+3 −15
Original line number Diff line number Diff line
@@ -179,21 +179,9 @@ class UpdateQuery(Query): 
        query = self.clone(klass=Query)

        query.bump_prefix()

        query.extra_select = {}

        first_table = query.tables[0]

        if query.alias_refcount[first_table] == 1:

            # We can remove one table from the inner query.

            query.unref_alias(first_table)

            for i in xrange(1, len(query.tables)):

                table = query.tables[i]

                if query.alias_refcount[table]:

                    break

            join_info = query.alias_map[table]

            query.select = [(join_info[RHS_ALIAS], join_info[RHS_JOIN_COL])]

            must_pre_select = False

        else:

        query.select = []

        query.add_fields([query.model._meta.pk.name])

            must_pre_select = not self.connection.features.update_can_self_select

        must_pre_select = count > 1 and not self.connection.features.update_can_self_select



        # Now we adjust the current query: reset the where clause and get rid

        # of all the tables we don't need (since they're in the sub-select).

tests/regressiontests/model_inheritance_regress/models.py

+9 −1
Original line number Diff line number Diff line
@@ -222,7 +222,7 @@ True 
>>> obj = SelfRefChild.objects.create(child_data=37, parent_data=42)

>>> obj.delete()



# Regression tests for #8076 - get_(next/previous)_by_date should 

# Regression tests for #8076 - get_(next/previous)_by_date should work.

>>> c1 = ArticleWithAuthor(headline='ArticleWithAuthor 1', author="Person 1", pub_date=datetime.datetime(2005, 8, 1, 3, 0))

>>> c1.save()

>>> c2 = ArticleWithAuthor(headline='ArticleWithAuthor 2', author="Person 2", pub_date=datetime.datetime(2005, 8, 1, 10, 0))
@@ -267,4 +267,12 @@ DoesNotExist: ArticleWithAuthor matching query does not exist. 
>>> fragment.find('pub_date', pos + 1) == -1

True



# It is possible to call update() and only change a field in an ancestor model

# (regression test for #10362).

>>> article = ArticleWithAuthor.objects.create(author="fred", headline="Hey there!", pub_date = datetime.datetime(2009, 3, 1, 8, 0, 0))

>>> ArticleWithAuthor.objects.filter(author="fred").update(headline="Oh, no!")

1

>>> ArticleWithAuthor.objects.filter(pk=article.pk).update(headline="Oh, no!")

1



"""}