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'Returns a list of (related-object, model) pairs. Similar to get_fields_with_model().'
def get_all_related_objects_with_model(self, local_only=False, include_hidden=False):
try: self._related_objects_cache except AttributeError: self._fill_related_objects_cache() predicates = [] if local_only: predicates.append((lambda k, v: (not v))) if (not include_hidden): predicates.append((lambda k, v: (not k.field.rel.is_hidden()))) return filt...
'Returns a list of (related-m2m-object, model) pairs. Similar to get_fields_with_model().'
def get_all_related_m2m_objects_with_model(self):
try: cache = self._related_many_to_many_cache except AttributeError: cache = self._fill_related_many_to_many_cache() return cache.items()
'Returns a list of parent classes leading to \'model\' (order from closet to most distant ancestor). This has to handle the case were \'model\' is a granparent or even more distant relation.'
def get_base_chain(self, model):
if (not self.parents): return if (model in self.parents): return [model] for parent in self.parents: res = parent._meta.get_base_chain(model) if res: res.insert(0, parent) return res raise TypeError(('%r is not an ancestor of this...
'Returns a list of all the ancestor of this model as a list. Useful for determining if something is an ancestor, regardless of lineage.'
def get_parent_list(self):
result = set() for parent in self.parents: result.add(parent) result.update(parent._meta.get_parent_list()) return result
'Returns the field on the current model which points to the given "ancestor". This is possible an indirect link (a pointer to a parent model, which points, eventually, to the ancestor). Used when constructing table joins for model inheritance. Returns None if the model isn\'t an ancestor of this one.'
def get_ancestor_link(self, ancestor):
if (ancestor in self.parents): return self.parents[ancestor] for parent in self.parents: parent_link = parent._meta.get_ancestor_link(ancestor) if parent_link: return (self.parents[parent] or parent_link)
'Returns a list of Options objects that are ordered with respect to this object.'
def get_ordered_objects(self):
if (not hasattr(self, '_ordered_objects')): objects = [] self._ordered_objects = objects return self._ordered_objects
'Returns the index of the primary key field in the self.fields list.'
def pk_index(self):
return self.fields.index(self.pk)
'Returns choices with a default blank choices included, for use as SelectField choices for this field. Analogue of django.db.models.fields.Field.get_choices, provided initially for utilisation by RelatedFilterSpec.'
def get_choices(self, include_blank=True, blank_choice=BLANK_CHOICE_DASH, limit_to_currently_related=False):
first_choice = ((include_blank and blank_choice) or []) queryset = self.model._default_manager.all() if limit_to_currently_related: queryset = queryset.complex_filter({('%s__isnull' % self.parent_model._meta.module_name): False}) lst = [(x._get_pk_val(), smart_unicode(x)) for x in queryset] ...
'Get the fields in this class that should be edited inline.'
def editable_fields(self):
return [f for f in (self.opts.fields + self.opts.many_to_many) if (f.editable and (f != self.field))]
'Fill in all the cache information. This method is threadsafe, in the sense that every caller will see the same state upon return, and if the cache is already initialised, it does no work.'
def _populate(self):
if self.loaded: return self.write_lock.acquire() try: if self.loaded: return for app_name in settings.INSTALLED_APPS: if (app_name in self.handled): continue self.load_app(app_name, True) if (not self.nesting_level): ...
'Loads the app with the provided fully qualified name, and returns the model module.'
def load_app(self, app_name, can_postpone=False):
self.handled[app_name] = None self.nesting_level += 1 app_module = import_module(app_name) try: models = import_module('.models', app_name) except ImportError: self.nesting_level -= 1 if (not module_has_submodule(app_module, 'models')): return None elif ca...
'Returns true if the model cache is fully populated. Useful for code that wants to cache the results of get_models() for themselves once it is safe to do so.'
def app_cache_ready(self):
return self.loaded
'Returns a list of all installed modules that contain models.'
def get_apps(self):
self._populate() apps = [(v, k) for (k, v) in self.app_store.items()] apps.sort() return [elt[1] for elt in apps]
'Returns the module containing the models for the given app_label. If the app has no models in it and \'emptyOK\' is True, returns None.'
def get_app(self, app_label, emptyOK=False):
self._populate() self.write_lock.acquire() try: for app_name in settings.INSTALLED_APPS: if (app_label == app_name.split('.')[(-1)]): mod = self.load_app(app_name, False) if (mod is None): if emptyOK: return None...
'Returns the map of known problems with the INSTALLED_APPS.'
def get_app_errors(self):
self._populate() return self.app_errors
'Given a module containing models, returns a list of the models. Otherwise returns a list of all installed models. By default, auto-created models (i.e., m2m models without an explicit intermediate table) are not included. However, if you specify include_auto_created=True, they will be. By default, models created to sa...
def get_models(self, app_mod=None, include_auto_created=False, include_deferred=False):
cache_key = (app_mod, include_auto_created, include_deferred) try: return self._get_models_cache[cache_key] except KeyError: pass self._populate() if app_mod: app_list = [self.app_models.get(app_mod.__name__.split('.')[(-2)], SortedDict())] else: app_list = self.a...
'Returns the model matching the given app_label and case-insensitive model_name. Returns None if no model is found.'
def get_model(self, app_label, model_name, seed_cache=True):
if seed_cache: self._populate() return self.app_models.get(app_label, SortedDict()).get(model_name.lower())
'Register a set of models as belonging to an app.'
def register_models(self, app_label, *models):
for model in models: model_name = model._meta.object_name.lower() model_dict = self.app_models.setdefault(app_label, SortedDict()) if (model_name in model_dict): fname1 = os.path.abspath(sys.modules[model.__module__].__file__) fname2 = os.path.abspath(sys.modules[mode...
'Add a node to the where-tree. If the data is a list or tuple, it is expected to be of the form (obj, lookup_type, value), where obj is a Constraint object, and is then slightly munged before being stored (to avoid storing any reference to field objects). Otherwise, the \'data\' is stored unchanged and can be any class...
def add(self, data, connector):
if (not isinstance(data, (list, tuple))): super(WhereNode, self).add(data, connector) return (obj, lookup_type, value) = data if (hasattr(value, '__iter__') and hasattr(value, 'next')): value = list(value) if isinstance(value, datetime.datetime): annotation = datetime.dat...
'Returns the SQL version of the where clause and the value to be substituted in. Returns None, None if this node is empty. If \'node\' is provided, that is the root of the SQL generation (generally not needed except by the internal implementation for recursion).'
def as_sql(self, qn, connection):
if (not self.children): return (None, []) result = [] result_params = [] empty = True for child in self.children: try: if hasattr(child, 'as_sql'): (sql, params) = child.as_sql(qn=qn, connection=connection) else: (sql, params) =...
'Turn a tuple (table_alias, column_name, db_type, lookup_type, value_annot, params) into valid SQL. Returns the string for the SQL fragment and the parameters to use for it.'
def make_atom(self, child, qn, connection):
(lvalue, lookup_type, value_annot, params_or_value) = child if hasattr(lvalue, 'process'): try: (lvalue, params) = lvalue.process(lookup_type, params_or_value, connection) except EmptyShortCircuit: raise EmptyResultSet else: params = Field().get_db_prep_lookup...
'Returns the SQL fragment used for the left-hand side of a column constraint (for example, the "T1.foo" portion in the clause "WHERE ... T1.foo = 6").'
def sql_for_columns(self, data, qn, connection):
(table_alias, name, db_type) = data if table_alias: lhs = ('%s.%s' % (qn(table_alias), qn(name))) else: lhs = qn(name) return (connection.ops.field_cast_sql(db_type) % lhs)
'Relabels the alias values of any children. \'change_map\' is a dictionary mapping old (current) alias values to the new values.'
def relabel_aliases(self, change_map, node=None):
if (not node): node = self for (pos, child) in enumerate(node.children): if hasattr(child, 'relabel_aliases'): child.relabel_aliases(change_map) elif isinstance(child, tree.Node): self.relabel_aliases(change_map, child) elif isinstance(child, (list, tuple)...
'Save the state of the Constraint for pickling. Fields aren\'t necessarily pickleable, because they can have callable default values. So, instead of pickling the field store a reference so we can restore it manually'
def __getstate__(self):
obj_dict = self.__dict__.copy() if self.field: obj_dict['model'] = self.field.model obj_dict['field_name'] = self.field.name del obj_dict['field'] return obj_dict
'Restore the constraint'
def __setstate__(self, data):
model = data.pop('model', None) field_name = data.pop('field_name', None) self.__dict__.update(data) if (model is not None): self.field = model._meta.get_field(field_name) else: self.field = None
'Returns a tuple of data suitable for inclusion in a WhereNode instance.'
def process(self, lookup_type, value, connection):
from django.db.models.base import ObjectDoesNotExist try: if self.field: params = self.field.get_db_prep_lookup(lookup_type, value, connection=connection, prepared=True) db_type = self.field.db_type(connection=connection) else: params = Field().get_db_prep_loo...
'Convert the database-returned value into a type that is consistent across database backends. By default, this defers to the underlying backend operations, but it can be overridden by Query classes for specific backends.'
def convert_values(self, value, field, connection):
return connection.ops.convert_values(value, field)
'Returns the query as a string of SQL with the parameter values substituted in. Parameter values won\'t necessarily be quoted correctly, since that is done by the database interface at execution time.'
def __str__(self):
(sql, params) = self.get_compiler(DEFAULT_DB_ALIAS).as_sql() return (sql % params)
'Pickling support.'
def __getstate__(self):
obj_dict = self.__dict__.copy() obj_dict['related_select_fields'] = [] obj_dict['related_select_cols'] = [] obj_dict['select_fields'] = [(((f is not None) and f.name) or None) for f in obj_dict['select_fields']] return obj_dict
'Unpickling support.'
def __setstate__(self, obj_dict):
opts = obj_dict['model']._meta obj_dict['select_fields'] = [(((name is not None) and opts.get_field(name)) or None) for name in obj_dict['select_fields']] self.__dict__.update(obj_dict)
'Returns the Options instance (the model._meta) from which to start processing. Normally, this is self.model._meta, but it can be changed by subclasses.'
def get_meta(self):
return self.model._meta
'Creates a copy of the current instance. The \'kwargs\' parameter can be used by clients to update attributes after copying has taken place.'
def clone(self, klass=None, memo=None, **kwargs):
obj = Empty() obj.__class__ = (klass or self.__class__) obj.model = self.model obj.alias_refcount = self.alias_refcount.copy() obj.alias_map = self.alias_map.copy() obj.table_map = self.table_map.copy() obj.join_map = self.join_map.copy() obj.rev_join_map = self.rev_join_map.copy() o...
'Convert the database-returned value into a type that is consistent across database backends. By default, this defers to the underlying backend operations, but it can be overridden by Query classes for specific backends.'
def convert_values(self, value, field, connection):
return connection.ops.convert_values(value, field)
'Resolve the value of aggregates returned by the database to consistent (and reasonable) types. This is required because of the predisposition of certain backends to return Decimal and long types when they are not needed.'
def resolve_aggregate(self, value, aggregate, connection):
if (value is None): if aggregate.is_ordinal: return 0 return value elif aggregate.is_ordinal: return int(value) elif aggregate.is_computed: return float(value) else: return self.convert_values(value, aggregate.field, connection)
'Returns the dictionary with the values of the existing aggregations.'
def get_aggregation(self, using):
if (not self.aggregate_select): return {} if (self.group_by is not None): from django.db.models.sql.subqueries import AggregateQuery query = AggregateQuery(self.model) obj = self.clone() for (alias, aggregate) in self.aggregate_select.items(): if aggregate.is_...
'Performs a COUNT() query using the current filter constraints.'
def get_count(self, using):
obj = self.clone() if ((len(self.select) > 1) or self.aggregate_select): from django.db.models.sql.subqueries import AggregateQuery subquery = obj subquery.clear_ordering(True) subquery.clear_limits() obj = AggregateQuery(obj.model) try: obj.add_subque...
'Merge the \'rhs\' query into the current one (with any \'rhs\' effects being applied *after* (that is, "to the right of") anything in the current query. \'rhs\' is not modified during a call to this function. The \'connector\' parameter describes how to connect filters from the \'rhs\' query.'
def combine(self, rhs, connector):
assert (self.model == rhs.model), 'Cannot combine queries on two different base models.' assert self.can_filter(), 'Cannot combine queries once a slice has been taken.' assert (self.distinct == rhs.distinct), 'Cannot combine a unique query with ...
'Converts the self.deferred_loading data structure to an alternate data structure, describing the field that *will* be loaded. This is used to compute the columns to select from the database and also by the QuerySet class to work out which fields are being initialised on each model. Models that have all their fields in...
def deferred_to_data(self, target, callback):
(field_names, defer) = self.deferred_loading if (not field_names): return columns = set() orig_opts = self.model._meta seen = {} must_include = {self.model: set([orig_opts.pk])} for field_name in field_names: parts = field_name.split(LOOKUP_SEP) cur_model = self.model...
'Callback used by deferred_to_columns(). The "target" parameter should be a set instance.'
def deferred_to_columns_cb(self, target, model, fields):
table = model._meta.db_table if (table not in target): target[table] = set() for field in fields: target[table].add(field.column)
'Returns a table alias for the given table_name and whether this is a new alias or not. If \'create\' is true, a new alias is always created. Otherwise, the most recently created alias for the table (if one exists) is reused.'
def table_alias(self, table_name, create=False):
current = self.table_map.get(table_name) if ((not create) and current): alias = current[0] self.alias_refcount[alias] += 1 return (alias, False) if current: alias = ('%s%d' % (self.alias_prefix, (len(self.alias_map) + 1))) current.append(alias) else: alias...
'Increases the reference count for this alias.'
def ref_alias(self, alias):
self.alias_refcount[alias] += 1
'Decreases the reference count for this alias.'
def unref_alias(self, alias):
self.alias_refcount[alias] -= 1
'Promotes the join type of an alias to an outer join if it\'s possible for the join to contain NULL values on the left. If \'unconditional\' is False, the join is only promoted if it is nullable, otherwise it is always promoted. Returns True if the join was promoted by this call.'
def promote_alias(self, alias, unconditional=False):
if ((unconditional or self.alias_map[alias][NULLABLE]) and (self.alias_map[alias][JOIN_TYPE] != self.LOUTER)): data = list(self.alias_map[alias]) data[JOIN_TYPE] = self.LOUTER self.alias_map[alias] = tuple(data) return True return False
'Walks along a chain of aliases, promoting the first nullable join and any joins following that. If \'must_promote\' is True, all the aliases in the chain are promoted.'
def promote_alias_chain(self, chain, must_promote=False):
for alias in chain: if self.promote_alias(alias, must_promote): must_promote = True
'Given a "before" copy of the alias_refcounts dictionary (as \'initial_refcounts\') and a collection of aliases that may have been changed or created, works out which aliases have been created since then and which ones haven\'t been used and promotes all of those aliases, plus any children of theirs in the alias tree, ...
def promote_unused_aliases(self, initial_refcounts, used_aliases):
considered = {} for alias in self.tables: if (alias not in used_aliases): continue if ((alias not in initial_refcounts) or (self.alias_refcount[alias] == initial_refcounts[alias])): parent = self.alias_map[alias][LHS_ALIAS] must_promote = considered.get(parent...
'Changes the aliases in change_map (which maps old-alias -> new-alias), relabelling any references to them in select columns and the where clause.'
def change_aliases(self, change_map):
assert (set(change_map.keys()).intersection(set(change_map.values())) == set()) self.where.relabel_aliases(change_map) self.having.relabel_aliases(change_map) for columns in [self.select, (self.group_by or [])]: for (pos, col) in enumerate(columns): if isinstance(col, (list, tuple)):...
'Changes the alias prefix to the next letter in the alphabet and relabels all the aliases. Even tables that previously had no alias will get an alias after this call (it\'s mostly used for nested queries and the outer query will already be using the non-aliased table name). Subclasses who create their own prefix should...
def bump_prefix(self, exceptions=()):
current = ord(self.alias_prefix) assert (current < ord('Z')) prefix = chr((current + 1)) self.alias_prefix = prefix change_map = {} for (pos, alias) in enumerate(self.tables): if (alias in exceptions): continue new_alias = ('%s%d' % (prefix, pos)) change_map[a...
'Returns the first alias for this query, after increasing its reference count.'
def get_initial_alias(self):
if self.tables: alias = self.tables[0] self.ref_alias(alias) else: alias = self.join((None, self.model._meta.db_table, None, None)) return alias
'Returns the number of tables in this query with a non-zero reference count.'
def count_active_tables(self):
return len([1 for count in self.alias_refcount.itervalues() if count])
'Returns an alias for the join in \'connection\', either reusing an existing alias for that join or creating a new one. \'connection\' is a tuple (lhs, table, lhs_col, col) where \'lhs\' is either an existing table alias or a table name. The join correspods to the SQL equivalent of:: lhs.lhs_col = table.col If \'always...
def join(self, connection, always_create=False, exclusions=(), promote=False, outer_if_first=False, nullable=False, reuse=None):
(lhs, table, lhs_col, col) = connection if (lhs in self.alias_map): lhs_table = self.alias_map[lhs][TABLE_NAME] else: lhs_table = lhs if (reuse and always_create and (table in self.table_map)): exclusions = set(self.table_map[table]).difference(reuse).union(set(exclusions)) ...
'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 meth...
def setup_inherited_models(self):
opts = self.model._meta root_alias = self.tables[0] seen = {None: root_alias} proxied_model = get_proxied_model(opts) for (field, model) in opts.get_fields_with_model(): if (model not in seen): if (model is proxied_model): seen[model] = root_alias else...
'Undoes the effects of setup_inherited_models(). Should be called whenever select columns (self.select) are set explicitly.'
def remove_inherited_models(self):
for (key, alias) in self.included_inherited_models.items(): if key: self.unref_alias(alias) self.included_inherited_models = {}
'Returns whether or not all elements of this q_object need to be put together in the HAVING clause.'
def need_force_having(self, q_object):
for child in q_object.children: if isinstance(child, Node): if self.need_force_having(child): return True elif (child[0].split(LOOKUP_SEP)[0] in self.aggregates): return True return False
'Adds a single aggregate expression to the Query'
def add_aggregate(self, aggregate, model, alias, is_summary):
opts = model._meta field_list = aggregate.lookup.split(LOOKUP_SEP) if ((len(field_list) == 1) and (aggregate.lookup in self.aggregates)): field_name = field_list[0] col = field_name source = self.aggregates[field_name] if (not is_summary): raise FieldError(("Canno...
'Add a single filter to the query. The \'filter_expr\' is a pair: (filter_string, value). E.g. (\'name__contains\', \'fred\') If \'negate\' is True, this is an exclude() filter. It\'s important to note that this method does not negate anything in the where-clause object when inserting the filter constraints. This is be...
def add_filter(self, filter_expr, connector=AND, negate=False, trim=False, can_reuse=None, process_extras=True, force_having=False):
(arg, value) = filter_expr parts = arg.split(LOOKUP_SEP) if (not parts): raise FieldError(('Cannot parse keyword query %r' % arg)) if ((len(parts) == 1) or (parts[(-1)] not in self.query_terms)): lookup_type = 'exact' else: lookup_type = parts.pop() having_cla...
'Adds a Q-object to the current filter. Can also be used to add anything that has an \'add_to_query()\' method.'
def add_q(self, q_object, used_aliases=None, force_having=False):
if (used_aliases is None): used_aliases = self.used_aliases if hasattr(q_object, 'add_to_query'): q_object.add_to_query(self, used_aliases) else: if (self.where and (q_object.connector != AND) and (len(q_object) > 1)): self.where.start_subtree(AND) subtree = T...
'Compute the necessary table joins for the passage through the fields given in \'names\'. \'opts\' is the Options class for the current model (which gives the table we are joining to), \'alias\' is the alias for the table we are joining to. If dupe_multis is True, any many-to-many or many-to-one joins will always creat...
def setup_joins(self, names, opts, alias, dupe_multis, allow_many=True, allow_explicit_fk=False, can_reuse=None, negate=False, process_extras=True):
joins = [alias] last = [0] dupe_set = set() exclusions = set() extra_filters = [] int_alias = None for (pos, name) in enumerate(names): if (int_alias is not None): exclusions.add(int_alias) exclusions.add(alias) last.append(len(joins)) if (name == ...
'Sometimes joins at the end of a multi-table sequence can be trimmed. If the final join is against the same column as we are comparing against, and is an inner join, we can go back one step in a join chain and compare against the LHS of the join instead (and then repeat the optimization). The result, potentially, invol...
def trim_joins(self, target, join_list, last, trim):
final = len(join_list) penultimate = last.pop() if (penultimate == final): penultimate = last.pop() if (trim and (len(join_list) > 1)): extra = join_list[penultimate:] join_list = join_list[:penultimate] final = penultimate penultimate = last.pop() col = s...
'For a column that is one of multiple pointing to the same table, update the internal data structures to note that this alias shouldn\'t be used for those other columns.'
def update_dupe_avoidance(self, opts, col, alias):
ident = id(opts) for name in opts.duplicate_targets[col]: try: self.dupe_avoidance[(ident, name)].add(alias) except KeyError: self.dupe_avoidance[(ident, name)] = set([alias])
'When doing an exclude against any kind of N-to-many relation, we need to use a subquery. This method constructs the nested query, given the original exclude filter (filter_expr) and the portion up to the first N-to-many relation field.'
def split_exclude(self, filter_expr, prefix, can_reuse):
query = Query(self.model) query.add_filter(filter_expr, can_reuse=can_reuse) query.bump_prefix() query.clear_ordering(True) query.set_start(prefix) (alias, col) = query.select[0] query.where.add((Constraint(alias, col, None), 'isnull', False), AND) self.add_filter((('%s__in' % prefix), q...
'Adjusts the limits on the rows retrieved. We use low/high to set these, as it makes it more Pythonic to read and write. When the SQL query is created, they are converted to the appropriate offset and limit values. Any limits passed in here are applied relative to the existing constraints. So low is added to the curren...
def set_limits(self, low=None, high=None):
if (high is not None): if (self.high_mark is not None): self.high_mark = min(self.high_mark, (self.low_mark + high)) else: self.high_mark = (self.low_mark + high) if (low is not None): if (self.high_mark is not None): self.low_mark = min(self.high_mark...
'Clears any existing limits.'
def clear_limits(self):
(self.low_mark, self.high_mark) = (0, None)
'Returns True if adding filters to this instance is still possible. Typically, this means no limits or offsets have been put on the results.'
def can_filter(self):
return ((not self.low_mark) and (self.high_mark is None))
'Clears the list of fields to select (but not extra_select columns). Some queryset types completely replace any existing list of select columns.'
def clear_select_fields(self):
self.select = [] self.select_fields = []
'Adds the given (model) fields to the select set. The field names are added in the order specified.'
def add_fields(self, field_names, allow_m2m=True):
alias = self.get_initial_alias() opts = self.get_meta() try: for name in field_names: (field, target, u2, joins, u3, u4) = self.setup_joins(name.split(LOOKUP_SEP), opts, alias, False, allow_m2m, True) final_alias = joins[(-1)] col = target.column if (l...
'Adds items from the \'ordering\' sequence to the query\'s "order by" clause. These items are either field names (not column names) -- possibly with a direction prefix (\'-\' or \'?\') -- or ordinals, corresponding to column positions in the \'select\' list. If \'ordering\' is empty, all ordering is cleared from the qu...
def add_ordering(self, *ordering):
errors = [] for item in ordering: if (not ORDER_PATTERN.match(item)): errors.append(item) if errors: raise FieldError(('Invalid order_by arguments: %s' % errors)) if ordering: self.order_by.extend(ordering) else: self.default_ordering = False
'Removes any ordering settings. If \'force_empty\' is True, there will be no ordering in the resulting query (not even the model\'s default).'
def clear_ordering(self, force_empty=False):
self.order_by = [] self.extra_order_by = () if force_empty: self.default_ordering = False
'Expands the GROUP BY clause required by the query. This will usually be the set of all non-aggregate fields in the return data. If the database backend supports grouping by the primary key, and the query would be equivalent, the optimization will be made automatically.'
def set_group_by(self):
self.group_by = [] for sel in self.select: self.group_by.append(sel)
'Converts the query to do count(...) or count(distinct(pk)) in order to get its size.'
def add_count_column(self):
if (not self.distinct): if (not self.select): count = self.aggregates_module.Count('*', is_summary=True) else: assert (len(self.select) == 1), ("Cannot add count col with multiple cols in 'select': %r" % self.select) count = self.aggrega...
'Sets up the select_related data structure so that we only select certain related models (as opposed to all models, when self.select_related=True).'
def add_select_related(self, fields):
field_dict = {} for field in fields: d = field_dict for part in field.split(LOOKUP_SEP): d = d.setdefault(part, {}) self.select_related = field_dict self.related_select_cols = [] self.related_select_fields = []
'Adds data to the various extra_* attributes for user-created additions to the query.'
def add_extra(self, select, select_params, where, params, tables, order_by):
if select: select_pairs = SortedDict() if select_params: param_iter = iter(select_params) else: param_iter = iter([]) for (name, entry) in select.items(): entry = force_unicode(entry) entry_params = [] pos = entry.find('%s')...
'Remove any fields from the deferred loading set.'
def clear_deferred_loading(self):
self.deferred_loading = (set(), True)
'Add the given list of model field names to the set of fields to exclude from loading from the database when automatic column selection is done. The new field names are added to any existing field names that are deferred (or removed from any existing field names that are marked as the only ones for immediate loading).'...
def add_deferred_loading(self, field_names):
(existing, defer) = self.deferred_loading if defer: self.deferred_loading = (existing.union(field_names), True) else: self.deferred_loading = (existing.difference(field_names), False)
'Add the given list of model field names to the set of fields to retrieve when the SQL is executed ("immediate loading" fields). The field names replace any existing immediate loading field names. If there are field names already specified for deferred loading, those names are removed from the new field_names before st...
def add_immediate_loading(self, field_names):
(existing, defer) = self.deferred_loading if defer: self.deferred_loading = (set(field_names).difference(existing), False) else: self.deferred_loading = (set(field_names), False)
'If any fields are marked to be deferred, returns a dictionary mapping models to a set of names in those fields that will be loaded. If a model is not in the returned dictionary, none of it\'s fields are deferred. If no fields are marked for deferral, returns an empty dictionary.'
def get_loaded_field_names(self):
collection = {} self.deferred_to_data(collection, self.get_loaded_field_names_cb) return collection
'Callback used by get_deferred_field_names().'
def get_loaded_field_names_cb(self, target, model, fields):
target[model] = set([f.name for f in fields])
'Set the mask of aggregates that will actually be returned by the SELECT'
def set_aggregate_mask(self, names):
if (names is None): self.aggregate_select_mask = None else: self.aggregate_select_mask = set(names) self._aggregate_select_cache = None
'Set the mask of extra select items that will be returned by SELECT, we don\'t actually remove them from the Query since they might be used later'
def set_extra_mask(self, names):
if (names is None): self.extra_select_mask = None else: self.extra_select_mask = set(names) self._extra_select_cache = None
'The SortedDict of aggregate columns that are not masked, and should be used in the SELECT clause. This result is cached for optimization purposes.'
def _aggregate_select(self):
if (self._aggregate_select_cache is not None): return self._aggregate_select_cache elif (self.aggregate_select_mask is not None): self._aggregate_select_cache = SortedDict([(k, v) for (k, v) in self.aggregates.items() if (k in self.aggregate_select_mask)]) return self._aggregate_select_c...
'Sets the table from which to start joining. The start position is specified by the related attribute from the base model. This will automatically set to the select column to be the column linked from the previous table. This method is primarily for internal use and the error checking isn\'t as friendly as add_filter()...
def set_start(self, start):
opts = self.model._meta alias = self.get_initial_alias() (field, col, opts, joins, last, extra) = self.setup_joins(start.split(LOOKUP_SEP), opts, alias, False) select_col = self.alias_map[joins[1]][LHS_JOIN_COL] select_alias = alias for alias in joins: self.unref_alias(alias) for ali...
'Instantiate an SQL aggregate * col is a column reference describing the subject field of the aggregate. It can be an alias, or a tuple describing a table and column name. * source is the underlying field or aggregate definition for the column reference. If the aggregate is not an ordinal or computed type, this referen...
def __init__(self, col, source=None, is_summary=False, **extra):
self.col = col self.source = source self.is_summary = is_summary self.extra = extra tmp = self while (tmp and isinstance(tmp, Aggregate)): if getattr(tmp, 'is_ordinal', False): tmp = ordinal_aggregate_field elif getattr(tmp, 'is_computed', False): tmp = co...
'Return the aggregate, rendered as SQL.'
def as_sql(self, qn, connection):
if hasattr(self.col, 'as_sql'): field_name = self.col.as_sql(qn, connection) elif isinstance(self.col, (list, tuple)): field_name = '.'.join([qn(c) for c in self.col]) else: field_name = self.col params = {'function': self.sql_function, 'field': field_name} params.update(self...
'Set up and execute delete queries for all the objects in pk_list. More than one physical query may be executed if there are a lot of values in pk_list.'
def delete_batch(self, pk_list, using, field=None):
if (not field): field = self.model._meta.pk for offset in range(0, len(pk_list), GET_ITERATOR_CHUNK_SIZE): where = self.where_class() where.add((Constraint(None, field.column, field), 'in', pk_list[offset:(offset + GET_ITERATOR_CHUNK_SIZE)]), AND) self.do_query(self.model._meta.d...
'Runs on initialization and after cloning. Any attributes that would normally be set in __init__ should go in here, instead, so that they are also set up after a clone() call.'
def _setup_query(self):
self.values = [] self.related_ids = None if (not hasattr(self, 'related_updates')): self.related_updates = {}
'Convert a dictionary of field name to value mappings into an update query. This is the entry point for the public update() method on querysets.'
def add_update_values(self, values):
values_seq = [] for (name, val) in values.iteritems(): (field, model, direct, m2m) = self.model._meta.get_field_by_name(name) if ((not direct) or m2m): raise FieldError(('Cannot update model field %r (only non-relations and foreign keys permitted).' % fi...
'Turn a sequence of (field, model, value) triples into an update query. Used by add_update_values() as well as the "fast" update path when saving models.'
def add_update_fields(self, values_seq):
self.values.extend(values_seq)
'Adds (name, value) to an update query for an ancestor model. Updates are coalesced so that we only run one update query per ancestor.'
def add_related_update(self, model, field, value):
try: self.related_updates[model].append((field, None, value)) except KeyError: self.related_updates[model] = [(field, None, value)]
'Returns a list of query objects: one for each update required to an ancestor model. Each query will have the same filtering conditions as the current query but will only update a single table.'
def get_related_updates(self):
if (not self.related_updates): return [] result = [] for (model, values) in self.related_updates.iteritems(): query = UpdateQuery(model) query.values = values if (self.related_ids is not None): query.add_filter(('pk__in', self.related_ids)) result.append(q...
'Set up the insert query from the \'insert_values\' dictionary. The dictionary gives the model field names and their target values. If \'raw_values\' is True, the values in the \'insert_values\' dictionary are inserted directly into the query, rather than passed as SQL parameters. This provides a way to insert NULL and...
def insert_values(self, insert_values, raw_values=False):
(placeholders, values) = ([], []) for (field, val) in insert_values: placeholders.append((field, val)) self.columns.append(field.column) values.append(val) if raw_values: self.values.extend([(None, v) for v in values]) else: self.params += tuple(values) se...
'Converts the query into a date extraction query.'
def add_date_select(self, field_name, lookup_type, order='ASC'):
try: result = self.setup_joins(field_name.split(LOOKUP_SEP), self.get_meta(), self.get_initial_alias(), False) except FieldError: raise FieldDoesNotExist(("%s has no field named '%s'" % (self.model._meta.object_name, field_name))) field = result[0] assert isinstance(field,...
'Does any necessary class setup immediately prior to producing SQL. This is for things that can\'t necessarily be done in __init__ because we might not have all the pieces in place at that time.'
def pre_sql_setup(self):
if (not self.query.tables): self.query.join((None, self.query.model._meta.db_table, None, None)) if ((not self.query.select) and self.query.default_cols and (not self.query.included_inherited_models)): self.query.setup_inherited_models() if (self.query.select_related and (not self.query.rela...
'A wrapper around connection.ops.quote_name that doesn\'t quote aliases for table names. This avoids problems with some SQL dialects that treat quoted strings specially (e.g. PostgreSQL).'
def quote_name_unless_alias(self, name):
if (name in self.quote_cache): return self.quote_cache[name] if (((name in self.query.alias_map) and (name not in self.query.table_map)) or (name in self.query.extra_select)): self.quote_cache[name] = name return name r = self.connection.ops.quote_name(name) self.quote_cache[name...
'Creates the SQL for this query. Returns the SQL string and list of parameters. If \'with_limits\' is False, any limit/offset information is not included in the query.'
def as_sql(self, with_limits=True, with_col_aliases=False):
if (with_limits and (self.query.low_mark == self.query.high_mark)): return ('', ()) self.pre_sql_setup() out_cols = self.get_columns(with_col_aliases) (ordering, ordering_group_by) = self.get_ordering() (from_, f_params) = self.get_from_clause() qn = self.quote_name_unless_alias (whe...
'Perform the same functionality as the as_sql() method, returning an SQL string and parameters. However, the alias prefixes are bumped beforehand (in a copy -- the current query isn\'t changed), and any ordering is removed if the query is unsliced. Used when nesting this query inside another.'
def as_nested_sql(self):
obj = self.query.clone() if ((obj.low_mark == 0) and (obj.high_mark is None)): obj.clear_ordering(True) obj.bump_prefix() return obj.get_compiler(connection=self.connection).as_sql()
'Returns the list of columns to use in the select statement. If no columns have been specified, returns all columns relating to fields in the model. If \'with_aliases\' is true, any column names that are duplicated (without the table names) are given unique aliases. This is needed in some cases to avoid ambiguity with ...
def get_columns(self, with_aliases=False):
qn = self.quote_name_unless_alias qn2 = self.connection.ops.quote_name result = [('(%s) AS %s' % (col[0], qn2(alias))) for (alias, col) in self.query.extra_select.iteritems()] aliases = set(self.query.extra_select.keys()) if with_aliases: col_aliases = aliases.copy() else: ...
'Computes the default columns for selecting every field in the base 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 dire...
def get_default_columns(self, with_aliases=False, col_aliases=None, start_alias=None, opts=None, as_pairs=False, local_only=False):
result = [] if (opts is None): opts = self.query.model._meta qn = self.quote_name_unless_alias qn2 = self.connection.ops.quote_name aliases = set() only_load = self.deferred_to_columns() proxied_model = get_proxied_model(opts) if start_alias: seen = {None: start_alias} ...
'Returns a tuple containing a list representing the SQL elements in the "order by" clause, and the list of SQL elements that need to be added to the GROUP BY clause as a result of the ordering. Also sets the ordering_aliases attribute on this instance to a list of extra aliases needed in the select. Determining the ord...
def get_ordering(self):
if self.query.extra_order_by: ordering = self.query.extra_order_by elif (not self.query.default_ordering): ordering = self.query.order_by else: ordering = (self.query.order_by or self.query.model._meta.ordering) qn = self.quote_name_unless_alias qn2 = self.connection.ops.quot...
'Returns the table alias (the name might be ambiguous, the alias will not be) and column name for ordering by the given \'name\' parameter. The \'name\' is of the form \'field1__field2__...__fieldN\'.'
def find_ordering_name(self, name, opts, alias=None, default_order='ASC', already_seen=None):
(name, order) = get_order_dir(name, default_order) pieces = name.split(LOOKUP_SEP) if (not alias): alias = self.query.get_initial_alias() (field, target, opts, joins, last, extra) = self.query.setup_joins(pieces, opts, alias, False) alias = joins[(-1)] col = target.column if (not fie...
'Returns a list of strings that are joined together to go after the "FROM" part of the query, as well as a list any extra parameters that need to be included. Sub-classes, can override this to create a from-clause via a "select". This should only be called after any SQL construction methods that might change the tables...
def get_from_clause(self):
result = [] qn = self.quote_name_unless_alias qn2 = self.connection.ops.quote_name first = True for alias in self.query.tables: if (not self.query.alias_refcount[alias]): continue try: (name, alias, join_type, lhs, lhs_col, col, nullable) = self.query.alias_ma...
'Returns a tuple representing the SQL elements in the "group by" clause.'
def get_grouping(self):
qn = self.quote_name_unless_alias (result, params) = ([], []) if (self.query.group_by is not None): if ((len(self.query.model._meta.fields) == len(self.query.select)) and self.connection.features.allows_group_by_pk): self.query.group_by = [(self.query.model._meta.db_table, self.query.mod...