diff --git a/django/db/models/__init__.py b/django/db/models/__init__.py index 86763d9..f5ab8eb 100644 --- a/django/db/models/__init__.py +++ b/django/db/models/__init__.py @@ -4,6 +4,7 @@ from django.core import validators from django.db import connection from django.db.models.loading import get_apps, get_app, get_models, get_model, register_models from django.db.models.query import Q +from django.db.models.sql.expressions import F from django.db.models.manager import Manager from django.db.models.base import Model, AdminOptions from django.db.models.fields import * diff --git a/django/db/models/sql/expressions.py b/django/db/models/sql/expressions.py new file mode 100644 index 0000000..0a933f5 --- /dev/null +++ b/django/db/models/sql/expressions.py @@ -0,0 +1,158 @@ +from copy import deepcopy +from datetime import datetime + +from django.utils import tree +from django.core.exceptions import FieldError +from django.db import connection +from django.db.models.fields import Field, FieldDoesNotExist +from django.db.models.query_utils import QueryWrapper + +class Expression(object): + """ + Base class for all sql expressions, expected by QuerySet.update. + """ + # Arithmetic connection types + ADD = '+' + SUB = '-' + MUL = '*' + DIV = '/' + MOD = '%%' + + # Bitwise connection types + AND = '&' + OR = '|' + + def _combine(self, other, conn, reversed, node=None): + if reversed: + obj = ExpressionNode([Literal(other)], conn) + obj.add(node or self, conn) + else: + obj = node or ExpressionNode([self], conn) + if isinstance(other, Expression): + obj.add(other, conn) + else: + obj.add(Literal(other), conn) + return obj + + def __add__(self, other): + return self._combine(other, self.ADD, False) + + def __sub__(self, other): + return self._combine(other, self.SUB, False) + + def __mul__(self, other): + return self._combine(other, self.MUL, False) + + def __div__(self, other): + return self._combine(other, self.DIV, False) + + def __mod__(self, other): + return self._combine(other, self.MOD, False) + + def __and__(self, other): + return self._combine(other, self.AND, False) + + def __or__(self, other): + return self._combine(other, self.OR, False) + + def __radd__(self, other): + return self._combine(other, self.ADD, True) + + def __rsub__(self, other): + return self._combine(other, self.SUB, True) + + def __rmul__(self, other): + return self._combine(other, self.MUL, True) + + def __rdiv__(self, other): + return self._combine(other, self.DIV, True) + + def __rmod__(self, other): + return self._combine(other, self.MOD, True) + + def __rand__(self, other): + return self._combine(other, self.AND, True) + + def __ror__(self, other): + return self._combine(other, self.OR, True) + + def as_sql(self, opts, field, prep_func=None, qn=None): + raise NotImplementedError + +class ExpressionNode(Expression, tree.Node): + default = None + + def __init__(self, children=None, connector=None, negated=False): + if children is not None and len(children) > 1 and connector is None: + raise TypeError('You have to specify a connector.') + super(ExpressionNode, self).__init__(children, connector, negated) + + def _combine(self, *args, **kwargs): + return super(ExpressionNode, self)._combine(node=deepcopy(self), *args, **kwargs) + + def as_sql(self, opts, field, prep_func=None, qn=None, node=None): + if not qn: + qn = connection.ops.quote_name + if node is None: + node = self + + result = [] + result_params = [] + for child in node.children: + if hasattr(child, 'as_sql'): + sql, params = child.as_sql(opts, field, prep_func, qn) + format = '%s' + else: + sql, params = self.as_sql(opts, field, prep_func, qn, child) + if len(child.children) > 1: + format = '(%s)' + else: + format = '%s' + if sql: + result.append(format % sql) + result_params.extend(params) + conn = ' %s ' % node.connector + return conn.join(result), result_params + +class Literal(Expression): + """ + An expression representing the given value. + """ + def __init__(self, value): + self.value = value + + def as_sql(self, opts, field, prep_func=None, qn=None): + if self.value is None: + return 'NULL', () + + if isinstance(self.value, datetime): + sql = connection.ops.datetime_cast_sql() + else: + sql = '%s' + params = prep_func and prep_func(self.value) or (self.value,) + + if isinstance(params, QueryWrapper): + return params.data + return sql, params + +class F(Expression): + """ + An expression representing the value of the given field. + """ + def __init__(self, name): + self.name = name + + def as_sql(self, opts, field, prep_func=None, qn=None): + if not qn: + qn = connection.ops.quote_name + + try: + src_field = opts.get_field(self.name) + except FieldDoesNotExist: + names = opts.get_all_field_names() + raise FieldError('Cannot resolve keyword %r into field. ' + 'Choices are: %s' % (self.name, ', '.join(names))) + + field_sql = connection.ops.field_cast_sql(src_field.db_type()) + lhs = '%s.%s' % (qn(opts.db_table), qn(src_field.column)) + return field_sql % lhs, () diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py index 3044882..567879b 100644 --- a/django/db/models/sql/query.py +++ b/django/db/models/sql/query.py @@ -250,7 +250,7 @@ class Query(object): # get_from_clause() for details. from_, f_params = self.get_from_clause() - where, w_params = self.where.as_sql(qn=self.quote_name_unless_alias) + where, w_params = self.where.as_sql(self.get_meta(), qn=self.quote_name_unless_alias) params = list(self.extra_select_params) result = ['SELECT'] diff --git a/django/db/models/sql/subqueries.py b/django/db/models/sql/subqueries.py index 28436ab..b64639c 100644 --- a/django/db/models/sql/subqueries.py +++ b/django/db/models/sql/subqueries.py @@ -7,6 +7,7 @@ from django.db.models.sql.constants import * from django.db.models.sql.datastructures import Date from django.db.models.sql.query import Query from django.db.models.sql.where import AND +from django.db.models.sql.expressions import Expression, Literal __all__ = ['DeleteQuery', 'UpdateQuery', 'InsertQuery', 'DateQuery', 'CountQuery'] @@ -24,7 +25,7 @@ class DeleteQuery(Query): assert len(self.tables) == 1, \ "Can only delete from one table at a time." result = ['DELETE FROM %s' % self.quote_name_unless_alias(self.tables[0])] - where, params = self.where.as_sql() + where, params = self.where.as_sql(self.get_meta()) result.append('WHERE %s' % where) return ' '.join(result), tuple(params) @@ -126,14 +127,11 @@ class UpdateQuery(Query): result = ['UPDATE %s' % qn(table)] result.append('SET') values, update_params = [], [] - for name, val, placeholder in self.values: - if val is not None: - values.append('%s = %s' % (qn(name), placeholder)) - update_params.append(val) - else: - values.append('%s = NULL' % qn(name)) + for name, sql, params in self.values: + values.append('%s = %s' % (qn(name), sql)) + update_params.extend(params) result.append(', '.join(values)) - where, params = self.where.as_sql() + where, params = self.where.as_sql(self.get_meta()) if where: result.append('WHERE %s' % where) return ' '.join(result), tuple(update_params + params) @@ -207,7 +205,7 @@ class UpdateQuery(Query): self.where.add((None, f.column, f, 'in', pk_list[offset : offset + GET_ITERATOR_CHUNK_SIZE]), AND) - self.values = [(related_field.column, None, '%s')] + self.values = [(related_field.column, 'NULL', ())] self.execute_sql(None) def add_update_values(self, values): @@ -232,31 +230,32 @@ class UpdateQuery(Query): """ from django.db.models.base import Model for field, model, val in values_seq: - # FIXME: Some sort of db_prep_* is probably more appropriate here. - if field.rel and isinstance(val, Model): - val = val.pk - - # Getting the placeholder for the field. - if hasattr(field, 'get_placeholder'): - placeholder = field.get_placeholder(val) + if isinstance(val, Expression): + expr = val else: - placeholder = '%s' + expr = Literal(val) + + sql, params = expr.as_sql( + self.get_meta(), + field, + lambda x: field.get_db_prep_lookup('exact', field.get_db_prep_save(x)), + self.connection.ops.quote_name) if model: - self.add_related_update(model, field.column, val, placeholder) + self.add_related_update(model, field.column, sql, params) else: - self.values.append((field.column, val, placeholder)) + self.values.append((field.column, sql, params)) - def add_related_update(self, model, column, value, placeholder): + def add_related_update(self, model, column, sql, params): """ Adds (name, value) to an update query for an ancestor model. Updates are coalesced so that we only run one update query per ancestor. """ try: - self.related_updates[model].append((column, value, placeholder)) + self.related_updates[model].append((column, sql, params)) except KeyError: - self.related_updates[model] = [(column, value, placeholder)] + self.related_updates[model] = [(column, sql, params)] def get_related_updates(self): """ @@ -312,22 +311,15 @@ class InsertQuery(Query): parameters. This provides a way to insert NULL and DEFAULT keywords into the query, for example. """ - placeholders, values = [], [] + values = [] for field, val in insert_values: - if hasattr(field, 'get_placeholder'): - # Some fields (e.g. geo fields) need special munging before - # they can be inserted. - placeholders.append(field.get_placeholder(val)) - else: - placeholders.append('%s') - self.columns.append(field.column) values.append(val) if raw_values: self.values.extend(values) else: self.params += tuple(values) - self.values.extend(placeholders) + self.values.extend(['%s'] * len(values)) class DateQuery(Query): """ diff --git a/django/db/models/sql/where.py b/django/db/models/sql/where.py index 14e5448..e98596b 100644 --- a/django/db/models/sql/where.py +++ b/django/db/models/sql/where.py @@ -4,9 +4,11 @@ Code to manage the creation and SQL rendering of 'where' constraints. import datetime from django.utils import tree +from django.utils.functional import curry from django.db import connection from django.db.models.fields import Field from django.db.models.query_utils import QueryWrapper +from django.db.models.sql.expressions import Expression, Literal from datastructures import EmptyResultSet, FullResultSet # Connection types @@ -26,7 +28,7 @@ class WhereNode(tree.Node): """ default = AND - def as_sql(self, node=None, qn=None): + def as_sql(self, opts, node=None, qn=None): """ Returns the SQL version of the where clause and the value to be substituted in. Returns None, None if this node is empty. @@ -47,10 +49,10 @@ class WhereNode(tree.Node): for child in node.children: try: if hasattr(child, 'as_sql'): - sql, params = child.as_sql(qn=qn) + sql, params = child.as_sql(opts, qn=qn) format = '(%s)' elif isinstance(child, tree.Node): - sql, params = self.as_sql(child, qn) + sql, params = self.as_sql(opts, child, qn) if child.negated: format = 'NOT (%s)' elif len(child.children) == 1: @@ -58,7 +60,7 @@ class WhereNode(tree.Node): else: format = '(%s)' else: - sql, params = self.make_atom(child, qn) + sql, params = self.make_atom(opts, child, qn) format = '%s' except EmptyResultSet: if node.connector == AND and not node.negated: @@ -86,7 +88,7 @@ class WhereNode(tree.Node): conn = ' %s ' % node.connector return conn.join(result), result_params - def make_atom(self, child, qn): + def make_atom(self, opts, child, qn): """ Turn a tuple (table_alias, field_name, field_class, lookup_type, value) into valid SQL. @@ -99,36 +101,39 @@ class WhereNode(tree.Node): lhs = '%s.%s' % (qn(table_alias), qn(name)) else: lhs = qn(name) + if not field: + field = Field() db_type = field and field.db_type() or None field_sql = connection.ops.field_cast_sql(db_type) % lhs + prep_func = curry(field.get_db_prep_lookup, lookup_type) - if isinstance(value, datetime.datetime): - cast_sql = connection.ops.datetime_cast_sql() - else: - cast_sql = '%s' + if lookup_type in connection.operators: + if isinstance(value, Expression): + sql, params = value.as_sql(opts, field, prep_func, qn) + else: + sql, params = Literal(value).as_sql(opts, field, prep_func, qn) - if field: - params = field.get_db_prep_lookup(lookup_type, value) - else: - params = Field().get_db_prep_lookup(lookup_type, value) + format = '%s %s' % ( + connection.ops.lookup_cast(lookup_type), + connection.operators[lookup_type]) + return format % (field_sql, sql), params + + if isinstance(value, Expression): + raise TypeError('Invalid lookup_type for use with %s object: %r' % ( + value.__class__.__name__, lookup_type)) + + params = prep_func(value) if isinstance(params, QueryWrapper): extra, params = params.data else: extra = '' - if lookup_type in connection.operators: - format = "%s %%s %s" % (connection.ops.lookup_cast(lookup_type), - extra) - return (format % (field_sql, - connection.operators[lookup_type] % cast_sql), params) - if lookup_type == 'in': if not value: raise EmptyResultSet if extra: return ('%s IN %s' % (field_sql, extra), params) - return ('%s IN (%s)' % (field_sql, ', '.join(['%s'] * len(value))), - params) + return ('%s IN (%s)' % (field_sql, ', '.join(['%s'] * len(value))), params) elif lookup_type in ('range', 'year'): return ('%s BETWEEN %%s and %%s' % field_sql, params) elif lookup_type in ('month', 'day'): @@ -164,7 +169,7 @@ class EverythingNode(object): """ A node that matches everything. """ - def as_sql(self, qn=None): + def as_sql(self, opts, qn=None): raise FullResultSet def relabel_aliases(self, change_map, node=None): diff --git a/tests/modeltests/expressions/models.py b/tests/modeltests/expressions/models.py new file mode 100644 index 0000000..bb92ee8 --- /dev/null +++ b/tests/modeltests/expressions/models.py @@ -0,0 +1,113 @@ +""" +Tests for the update() queryset method that allows in-place, multi-object +updates. +""" + +from django.db import models + +# +# Model for testing arithmetic expressions. +# + +class Number(models.Model): + integer = models.IntegerField() + float = models.FloatField(null=True) + + def __unicode__(self): + return u'%i, %.3f' % (self.integer, self.float) + +# +# A more ordinary use case. +# + +class Employee(models.Model): + firstname = models.CharField(max_length=50) + lastname = models.CharField(max_length=50) + + def __unicode__(self): + return u'%s %s' % (self.firstname, self.lastname) + +class Company(models.Model): + name = models.CharField(max_length=100) + num_employees = models.PositiveIntegerField() + num_chairs = models.PositiveIntegerField() + ceo = models.ForeignKey( + Employee, + related_name='company_ceo_set') + point_of_contact = models.ForeignKey( + Employee, + related_name='company_point_of_contact_set', + null=True) + + def __unicode__(self): + return self.name + + +__test__ = {'API_TESTS': """ +>>> from django.db.models import F + +>>> Number(integer=-1).save() +>>> Number(integer=42).save() +>>> Number(integer=1337).save() + +We can fill a value in all objects with an other value of the same object. + +>>> Number.objects.update(float=F('integer')) +>>> Number.objects.all() +[, , ] + +We can increment a value of all objects in a query set. + +>>> Number.objects.filter(integer__gt=0).update(integer=F('integer') + 1) +>>> Number.objects.all() +[, , ] + +We can filter for objects, where a value is not equals the value of an other field. + +>>> Number.objects.exclude(float=F('integer')) +[, ] + +Complex expressions of different connection types are possible. + +>>> n = Number.objects.create(integer=10, float=123.45) +>>> Number.objects.filter(pk=n.pk).update(float=F('integer') + F('float') * 2) +>>> Number.objects.get(pk=n.pk) + + +All supported operators, work as expected in native and reverse order. + +>>> from operator import add, sub, mul, div, mod, and_, or_ +>>> for op in (add, sub, mul, div, mod, and_, or_): +... n = Number.objects.create(integer=42, float=15.) +... Number.objects.filter(pk=n.pk).update( +... integer=op(F('integer'), 15), float=op(42., F('float'))) +... Number.objects.get(pk=n.pk) + + + + + + + + + +>>> Company(name='Example Inc.', num_employees=2300, num_chairs=5, +... ceo=Employee.objects.create(firstname='Joe', lastname='Smith')).save() +>>> Company(name='Foobar Ltd.', num_employees=3, num_chairs=3, +... ceo=Employee.objects.create(firstname='Frank', lastname='Meyer')).save() +>>> Company(name='Test GmbH', num_employees=32, num_chairs=1, +... ceo=Employee.objects.create(firstname='Max', lastname='Mustermann')).save() + +We can filter for companies where the number of employees is greater than the +number of chairs. + +>>> Company.objects.filter(num_employees__gt=F('num_chairs')) +[, ] + +The relation of a foreign key can become copied over to an other foreign key. + +>>> Company.objects.update(point_of_contact=F('ceo')) +>>> [c.point_of_contact for c in Company.objects.all()] +[, , ] + +"""} diff --git a/tests/modeltests/update/models.py b/tests/modeltests/update/models.py index 8a35b61..1df1811 100644 --- a/tests/modeltests/update/models.py +++ b/tests/modeltests/update/models.py @@ -4,71 +4,83 @@ updates. """ from django.db import models +from django.conf import settings -class DataPoint(models.Model): +class Product(models.Model): name = models.CharField(max_length=20) - value = models.CharField(max_length=20) - another_value = models.CharField(max_length=20, blank=True) + description = models.CharField(max_length=20) + expires = models.DateTimeField(null=True) def __unicode__(self): return unicode(self.name) -class RelatedPoint(models.Model): +class RelatedProduct(models.Model): name = models.CharField(max_length=20) - data = models.ForeignKey(DataPoint) + data = models.ForeignKey(Product) def __unicode__(self): return unicode(self.name) __test__ = {'API_TESTS': """ ->>> DataPoint(name="d0", value="apple").save() ->>> DataPoint(name="d2", value="banana").save() ->>> d3 = DataPoint(name="d3", value="banana") ->>> d3.save() ->>> RelatedPoint(name="r1", data=d3).save() +>>> from datetime import datetime + +>>> Product(name="p0", description="apple").save() +>>> Product(name="p2", description="banana").save() +>>> p3 = Product(name="p3", description="banana") +>>> p3.save() +>>> RelatedProduct(name="r1", data=p3).save() Objects are updated by first filtering the candidates into a queryset and then calling the update() method. It executes immediately and returns nothing. ->>> DataPoint.objects.filter(value="apple").update(name="d1") ->>> DataPoint.objects.filter(value="apple") -[] +>>> Product.objects.filter(description="apple").update(name="p1") +>>> Product.objects.filter(description="apple") +[] We can update multiple objects at once. ->>> DataPoint.objects.filter(value="banana").update(value="pineapple") ->>> DataPoint.objects.get(name="d2").value +>>> Product.objects.filter(description="banana").update(description="pineapple") +>>> Product.objects.get(name="p2").description u'pineapple' Foreign key fields can also be updated, although you can only update the object referred to, not anything inside the related object. ->>> d = DataPoint.objects.get(name="d1") ->>> RelatedPoint.objects.filter(name="r1").update(data=d) ->>> RelatedPoint.objects.filter(data__name="d1") -[] +>>> p = Product.objects.get(name="p1") +>>> RelatedProduct.objects.filter(name="r1").update(data=p) +>>> RelatedProduct.objects.filter(data__name="p1") +[] + +Multiple fields can be updated at once. If DATABASE_ENGINE is mysql microseconds +must be truncated. + +>>> Product.objects.filter(description="pineapple").update( +... description="fruit", +... expires=datetime(2010, 1, 1, 12, 0, 0, 123456)) +>>> p = Product.objects.get(name="p2") +>>> p.description, p.expires +"""} -Multiple fields can be updated at once +if settings.DATABASE_ENGINE == 'mysql': + __test__['API_TESTS'] += "(u'fruit', datetime.datetime(2010, 1, 1, 12, 0))" +else: + __test__['API_TESTS'] += "(u'fruit', datetime.datetime(2010, 1, 1, 12, 0, 0, 123456))" ->>> DataPoint.objects.filter(value="pineapple").update(value="fruit", another_value="peaches") ->>> d = DataPoint.objects.get(name="d2") ->>> d.value, d.another_value -(u'fruit', u'peaches') +__test__['API_TESTS'] += """ In the rare case you want to update every instance of a model, update() is also -a manager method. +a manager method and update with None works as well. ->>> DataPoint.objects.update(value='thing') ->>> DataPoint.objects.values('value').distinct() -[{'value': u'thing'}] +>>> Product.objects.update(expires=None) +>>> Product.objects.values('expires').distinct() +[{'expires': None}] We do not support update on already sliced query sets. ->>> DataPoint.objects.all()[:2].update(another_value='another thing') +>>> Product.objects.all()[:2].update(another_value='another thing') Traceback (most recent call last): ... AssertionError: Cannot update a query once a slice has been taken. """ -}