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Code Issues 32 Releases Wiki Activity

magic-removal: Fixed #1186 -- Fixed problem resolving primary key in some 'pk' database queries. Also lightly refactored query-parsing code. Thanks, Russ

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git-svn-id: http://code.djangoproject.com/svn/django/branches/magic-removal@1856 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Adrian Holovaty 2006-01-08 06:16:05 +00:00
parent 2bc39d88e6
commit f998c7bcc6
7 changed files with 333 additions and 172 deletions
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360
django/db/models/query.py
View File

@ -1,5 +1,6 @@
from django.db import backend, connection
from django.db.models.exceptions import *
from django.utils.datastructures import SortedDict
LOOKUP_SEPARATOR = '__'
@ -170,15 +171,14 @@ def fill_table_cache(opts, select, tables, where, old_prefix, cache_tables_seen)
select.extend(['%s.%s' % (backend.quote_name(db_table), backend.quote_name(f2.column)) for f2 in f.rel.to._meta.fields])
fill_table_cache(f.rel.to._meta, select, tables, where, db_table, cache_tables_seen)
def throw_bad_kwarg_error(kwarg):
# Helper function to remove redundancy.
raise TypeError, "got unexpected keyword argument '%s'" % kwarg
def parse_lookup(kwarg_items, opts):
# Helper function that handles converting API kwargs (e.g.
# "name__exact": "tom") to SQL.
# Helper function that handles converting API kwargs
# (e.g. "name__exact": "tom") to SQL.
# 'joins' is a dictionary describing the tables that must be joined to complete the query.
# 'joins' is a sorted dictionary describing the tables that must be joined
# to complete the query. The dictionary is sorted because creation order
# is significant; it is a dictionary to ensure uniqueness of alias names.
#
# Each key-value pair follows the form
# alias: (table, join_type, condition)
# where
@ -186,177 +186,203 @@ def parse_lookup(kwarg_items, opts):
# table is the actual table name to be joined
# join_type is the type of join (INNER JOIN, LEFT OUTER JOIN, etc)
# condition is the where-like statement over which narrows the join.
# alias will be derived from the lookup list name.
#
# alias will be derived from the lookup list name.
# At present, this method only every returns INNER JOINs; the option is there for others
# to implement custom Q()s, etc that return other join types.
tables, joins, where, params = [], {}, [], []
for kwarg, kwarg_value in kwarg_items:
# At present, this method only every returns INNER JOINs; the option is
# there for others to implement custom Q()s, etc that return other join
# types.
tables, joins, where, params = [], SortedDict(), [], []
for kwarg, value in kwarg_items:
if kwarg in ('order_by', 'limit', 'offset', 'select_related', 'distinct', 'select', 'tables', 'where', 'params'):
continue
if kwarg_value is None:
continue
if kwarg == 'complex':
tables2, joins2, where2, params2 = kwarg_value.get_sql(opts)
pass
elif value is None:
pass
elif kwarg == 'complex':
tables2, joins2, where2, params2 = value.get_sql(opts)
tables.extend(tables2)
joins.update(joins2)
where.extend(where2)
params.extend(params2)
continue
if kwarg == '_or':
for val in kwarg_value:
elif kwarg == '_or':
for val in value:
tables2, joins2, where2, params2 = parse_lookup(val, opts)
tables.extend(tables2)
joins.update(joins2)
where.append('(%s)' % ' OR '.join(where2))
params.extend(params2)
continue
lookup_list = kwarg.split(LOOKUP_SEPARATOR)
# pk="value" is shorthand for (primary key)__exact="value"
if lookup_list[-1] == 'pk':
if opts.pk.rel:
lookup_list = lookup_list[:-1] + [opts.pk.name, opts.pk.rel.field_name, 'exact']
else:
lookup_list = lookup_list[:-1] + [opts.pk.name, 'exact']
if len(lookup_list) == 1:
throw_bad_kwarg_error(kwarg)
lookup_type = lookup_list.pop()
current_opts = opts # We'll be overwriting this, so keep a reference to the original opts.
current_table_alias = current_opts.db_table
param_required = False
while lookup_list or param_required:
try:
# "current" is a piece of the lookup list. For example, in
# choices.get_list(poll__sites__id__exact=5), lookup_list is
# ["poll", "sites", "id"], and the first current is "poll".
try:
current = lookup_list.pop(0)
except IndexError:
# If we're here, lookup_list is empty but param_required
# is set to True, which means the kwarg was bad.
# Example: choices.get_list(poll__exact='foo')
throw_bad_kwarg_error(kwarg)
# Try many-to-many relationships in the direction in which they are
# originally defined (i.e., the class that defines the ManyToManyField)
for f in current_opts.many_to_many:
if f.name == current:
rel_table_alias = backend.quote_name("m2m_" + current_table_alias + LOOKUP_SEPARATOR + current)
else: # Must be a search parameter.
path = kwarg.split(LOOKUP_SEPARATOR)
joins[rel_table_alias] = (
backend.quote_name(f.get_m2m_db_table(current_opts)),
"INNER JOIN",
'%s.%s = %s.%s' %
(backend.quote_name(current_table_alias),
backend.quote_name(current_opts.pk.column),
rel_table_alias,
backend.quote_name(current_opts.object_name.lower() + '_id'))
)
# Extract the last elements of the kwarg.
# The very-last is the clause (equals, like, etc).
# The second-last is the table column on which the clause is
# to be performed.
# The only exception to this is "pk", which is an implicit
# id__exact; if we find "pk", make the clause "exact', and
# insert a dummy name of None, which we will replace when
# we know which table column to grab as the primary key.
clause = path.pop()
if clause == 'pk':
clause = 'exact'
path.append(None)
if len(path) < 1:
raise TypeError, "Cannot parse keyword query %r" % kwarg
tables2, joins2, where2, params2 = lookup_inner(path, clause, value, opts, opts.db_table, None)
tables.extend(tables2)
joins.update(joins2)
where.extend(where2)
params.extend(params2)
return tables, joins, where, params
class FieldFound(Exception):
"Exception used to short circuit field-finding operations."
pass
def find_field(name, field_list):
"""
Finds a field with a specific name in a list of field instances.
Returns None if there are no matches, or several matches.
"""
matches = [f for f in field_list if f.name == name]
if len(matches) != 1:
return None
return matches[0]
def lookup_inner(path, clause, value, opts, table, column):
tables, joins, where, params = [], SortedDict(), [], []
current_opts = opts
current_table = table
current_column = column
intermediate_table = None
join_required = False
name = path.pop(0)
# Has the primary key been requested? If so, expand it out
# to be the name of the current class' primary key
if name is None:
name = current_opts.pk.name
# Try to find the name in the fields associated with the current class
try:
# Does the name belong to a defined many-to-many field?
field = find_field(name, current_opts.many_to_many)
if field:
new_table = current_table + LOOKUP_SEPARATOR + name
new_opts = field.rel.to._meta
new_column = new_opts.pk.column
# Need to create an intermediate table join over the m2m table
# This process hijacks current_table/column to point to the
# intermediate table.
current_table = "m2m_" + new_table
join_column = new_opts.object_name.lower() + '_id'
intermediate_table = field.get_m2m_db_table(current_opts)
raise FieldFound()
# Does the name belong to a reverse defined many-to-many field?
field = find_field(name, current_opts.get_all_related_many_to_many_objects())
if field:
new_table = current_table + LOOKUP_SEPARATOR + name
new_opts = field.opts
new_column = new_opts.pk.column
# Need to create an intermediate table join over the m2m table.
# This process hijacks current_table/column to point to the
# intermediate table.
current_table = "m2m_" + new_table
join_column = new_opts.object_name.lower() + '_id'
intermediate_table = field.field.get_m2m_db_table(new_opts)
raise FieldFound()
# Does the name belong to a one-to-many field?
field = find_field(name, opts.get_all_related_objects())
if field:
new_table = table + LOOKUP_SEPARATOR + name
new_opts = field.opts
new_column = field.field.column
join_column = opts.pk.column
# 1-N fields MUST be joined, regardless of any other conditions.
join_required = True
raise FieldFound()
# Does the name belong to a one-to-one, many-to-one, or regular field?
field = find_field(name, current_opts.fields)
if field:
if field.rel: # One-to-One/Many-to-one field
new_table = current_table + LOOKUP_SEPARATOR + name
new_opts = field.rel.to._meta
new_column = new_opts.pk.column
join_column = field.column
raise FieldFound()
except FieldFound: # Match found, loop has been shortcut.
pass
except: # Any other exception; rethrow
raise
else: # No match found.
raise TypeError, "Cannot resolve keyword '%s' into field" % name
# Check to see if an intermediate join is required between current_table
# and new_table.
if intermediate_table:
joins[backend.quote_name(current_table)] = (
backend.quote_name(intermediate_table),
"INNER JOIN",
"%s.%s = %s.%s" % \
(backend.quote_name(table),
backend.quote_name(current_opts.pk.column),
backend.quote_name(current_table),
backend.quote_name(current_opts.object_name.lower() + '_id'))
)
if path:
if len(path) == 1 and path[0] in (new_opts.pk.name, None) \
and clause in ('exact', 'isnull') and not join_required:
# If the last name query is for a key, and the search is for
# isnull/exact, then the current (for N-1) or intermediate
# (for N-N) table can be used for the search - no need to join an
# extra table just to check the primary key.
new_table = current_table
else:
# There are 1 or more name queries pending, and we have ruled out
# any shortcuts; therefore, a join is required.
joins[backend.quote_name(new_table)] = (
backend.quote_name(new_opts.db_table),
"INNER JOIN",
"%s.%s = %s.%s" %
(backend.quote_name(current_table),
backend.quote_name(join_column),
backend.quote_name(new_table),
backend.quote_name(new_column))
)
# If we have made the join, we don't need to tell subsequent
# recursive calls about the column name we joined on.
join_column = None
# There are name queries remaining. Recurse deeper.
tables2, joins2, where2, params2 = lookup_inner(path, clause, value, new_opts, new_table, join_column)
tables.extend(tables2)
joins.update(joins2)
where.extend(where2)
params.extend(params2)
else:
# Evaluate clause on current table.
if name in (current_opts.pk.name, None) and clause in ('exact', 'isnull') and current_column:
# If this is an exact/isnull key search, and the last pass
# found/introduced a current/intermediate table that we can use to
# optimize the query, then use that column name.
column = current_column
else:
column = field.column
where.append(get_where_clause(clause, current_table + '.', column, value))
params.extend(field.get_db_prep_lookup(clause, value))
# Optimization: In the case of primary-key lookups, we
# don't have to do an extra join.
if lookup_list and lookup_list[0] == f.rel.to._meta.pk.name and lookup_type == 'exact':
where.append(get_where_clause(lookup_type, rel_table_alias+'.',
f.rel.to._meta.object_name.lower()+'_id', kwarg_value))
params.extend(f.get_db_prep_lookup(lookup_type, kwarg_value))
lookup_list.pop()
param_required = False
else:
new_table_alias = current_table_alias + LOOKUP_SEPARATOR + current
joins[backend.quote_name(new_table_alias)] = (
backend.quote_name(f.rel.to._meta.db_table),
"INNER JOIN",
'%s.%s = %s.%s' %
(rel_table_alias,
backend.quote_name(f.rel.to._meta.object_name.lower() + '_id'),
backend.quote_name(new_table_alias),
backend.quote_name(f.rel.to._meta.pk.column))
)
current_table_alias = new_table_alias
param_required = True
current_opts = f.rel.to._meta
raise StopIteration
# Try many-to-many relationships first in the reverse direction
# (i.e., from the class does not have the ManyToManyField)
for f in current_opts.get_all_related_many_to_many_objects():
if f.name == current:
rel_table_alias = backend.quote_name("m2m_" + current_table_alias + LOOKUP_SEPARATOR + current)
joins[rel_table_alias] = (
backend.quote_name(f.field.get_m2m_db_table(f.opts)),
"INNER JOIN",
'%s.%s = %s.%s' %
(backend.quote_name(current_table_alias),
backend.quote_name(current_opts.pk.column),
rel_table_alias,
backend.quote_name(current_opts.object_name.lower() + '_id'))
)
# Optimization: In the case of primary-key lookups, we
# don't have to do an extra join.
if lookup_list and lookup_list[0] == f.opts.pk.name and lookup_type == 'exact':
where.append(get_where_clause(lookup_type, rel_table_alias+'.',
f.opts.object_name.lower()+'_id', kwarg_value))
params.extend(f.field.get_db_prep_lookup(lookup_type, kwarg_value))
lookup_list.pop()
param_required = False
else:
new_table_alias = current_table_alias + LOOKUP_SEPARATOR + current
joins[backend.quote_name(new_table_alias)] = (
backend.quote_name(f.opts.db_table),
"INNER JOIN",
'%s.%s = %s.%s' %
(rel_table_alias,
backend.quote_name(f.opts.object_name.lower() + '_id'),
backend.quote_name(new_table_alias),
backend.quote_name(f.opts.pk.column))
)
current_table_alias = new_table_alias
param_required = True
current_opts = f.opts
raise StopIteration
for f in current_opts.fields:
# Try many-to-one relationships...
if f.rel and f.name == current:
# Optimization: In the case of primary-key lookups, we
# don't have to do an extra join.
if lookup_list and lookup_list[0] == f.rel.to._meta.pk.name and lookup_type == 'exact':
where.append(get_where_clause(lookup_type, current_table_alias+'.', f.column, kwarg_value))
params.extend(f.get_db_prep_lookup(lookup_type, kwarg_value))
lookup_list.pop()
param_required = False
# 'isnull' lookups in many-to-one relationships are a special case,
# because we don't want to do a join. We just want to find out
# whether the foreign key field is NULL.
elif lookup_type == 'isnull' and not lookup_list:
where.append(get_where_clause(lookup_type, current_table_alias+'.', f.column, kwarg_value))
params.extend(f.get_db_prep_lookup(lookup_type, kwarg_value))
else:
new_table_alias = current_table_alias + LOOKUP_SEPARATOR + current
joins[backend.quote_name(new_table_alias)] = (
backend.quote_name(f.rel.to._meta.db_table),
"INNER JOIN",
'%s.%s = %s.%s' %
(backend.quote_name(current_table_alias),
backend.quote_name(f.column),
backend.quote_name(new_table_alias),
backend.quote_name(f.rel.to._meta.pk.column))
)
current_table_alias = new_table_alias
param_required = True
current_opts = f.rel.to._meta
raise StopIteration
# Try direct field-name lookups...
if f.name == current:
where.append(get_where_clause(lookup_type, current_table_alias+'.', f.column, kwarg_value))
params.extend(f.get_db_prep_lookup(lookup_type, kwarg_value))
param_required = False
raise StopIteration
# If we haven't hit StopIteration at this point, "current" must be
# an invalid lookup, so raise an exception.
throw_bad_kwarg_error(kwarg)
except StopIteration:
continue
return tables, joins, where, params

35
django/utils/datastructures.py
View File

@ -40,6 +40,41 @@ class MergeDict:
return True
return False
class SortedDict(dict):
"A dictionary that keeps its keys in the order in which they're inserted."
def __init__(self, data={}):
dict.__init__(self, data)
self.keyOrder = data.keys()
def __setitem__(self, key, value):
dict.__setitem__(self, key, value)
if key not in self.keyOrder:
self.keyOrder.append(key)
def __delitem__(self, key, value):
dict.__delitem__(self, key, value)
self.keyOrder.remove(key)
def __iter__(self):
for k in self.keyOrder:
yield k
def items(self):
for k in self.keyOrder:
yield k, dict.__getitem__(self, k)
def keys(self):
for k in self.keyOrder:
yield k
def values(self):
for k in self.keyOrder:
yield dict.__getitem__(self, k)
def update(self, dict):
for k, v in dict.items():
self.__setitem__(k, v)
class MultiValueDictKeyError(KeyError):
pass

2
tests/modeltests/custom_columns/models.py
View File

@ -35,7 +35,7 @@ John Smith
>>> Person.objects.get_list(firstname__exact='John')
Traceback (most recent call last):
...
TypeError: got unexpected keyword argument 'firstname__exact'
TypeError: Cannot resolve keyword 'firstname' into field
>>> p = Person.objects.get_object(last_name__exact='Smith')
>>> p.first_name

23
tests/modeltests/custom_pk/models.py
View File

@ -47,6 +47,10 @@ Traceback (most recent call last):
...
DoesNotExist: Employee does not exist for {'pk': 'foo'}
# Use the name of the primary key, rather than pk.
>>> Employee.objects.get_object(employee_code__exact='ABC123')
Dan Jones
# Fran got married and changed her last name.
>>> fran = Employee.objects.get_object(pk='XYZ456')
>>> fran.last_name = 'Jones'
@ -66,4 +70,23 @@ True
[Sears]
>>> Business.objects.get_in_bulk(['Sears'])
{'Sears': Sears}
>>> Business.objects.get_list(name__exact='Sears')
[Sears]
>>> Business.objects.get_list(pk='Sears')
[Sears]
# Queries across tables, involving primary key
>>> Employee.objects.get_list(businesses__name__exact='Sears')
[Dan Jones, Fran Jones]
>>> Employee.objects.get_list(businesses__pk='Sears')
[Dan Jones, Fran Jones]
>>> Business.objects.get_list(employees__employee_code__exact='ABC123')
[Sears]
>>> Business.objects.get_list(employees__pk='ABC123')
[Sears]
>>> Business.objects.get_list(employees__first_name__startswith='Fran')
[Sears]
"""

10
tests/modeltests/many_to_many/models.py
View File

@ -68,6 +68,8 @@ True
[Django lets you build Web apps easily, NASA uses Python]
# We can perform kwarg queries across m2m relationships
>>> Article.objects.get_list(publications__id__exact=1)
[Django lets you build Web apps easily, NASA uses Python]
>>> Article.objects.get_list(publications__pk=1)
[Django lets you build Web apps easily, NASA uses Python]
@ -78,9 +80,17 @@ True
[NASA uses Python]
# Reverse m2m queries (i.e., start at the table that doesn't have a ManyToManyField)
>>> Publication.objects.get_list(id__exact=1)
[The Python Journal]
>>> Publication.objects.get_list(pk=1)
[The Python Journal]
>>> Publication.objects.get_list(articles__headline__startswith="NASA")
[The Python Journal, Science News, Science Weekly]
>>> Publication.objects.get_list(articles__id__exact=1)
[The Python Journal]
>>> Publication.objects.get_list(articles__pk=1)
[The Python Journal]

47
tests/modeltests/many_to_one/models.py
View File

@ -22,6 +22,7 @@ class Article(models.Model):
def __repr__(self):
return self.headline
API_TESTS = """
# Create a Reporter.
>>> r = Reporter(first_name='John', last_name='Smith', email='john@example.com')
@ -60,6 +61,16 @@ This is a test
>>> r.get_article_count()
2
# Get articles by id
>>> Article.objects.get_list(id__exact=1)
[This is a test]
>>> Article.objects.get_list(pk=1)
[This is a test]
# Query on an article property
>>> Article.objects.get_list(headline__startswith='This')
[This is a test]
# The API automatically follows relationships as far as you need.
# Use double underscores to separate relationships.
# This works as many levels deep as you want. There's no limit.
@ -83,12 +94,20 @@ This is a test
# Find all Articles for the Reporter whose ID is 1.
>>> Article.objects.get_list(reporter__id__exact=1, order_by=['pub_date'])
[This is a test, John's second story]
>>> Article.objects.get_list(reporter__pk=1, order_by=['pub_date'])
[This is a test, John's second story]
# Note you need two underscores between "reporter" and "id" -- not one.
# You need two underscores between "reporter" and "id" -- not one.
>>> Article.objects.get_list(reporter_id__exact=1)
Traceback (most recent call last):
...
TypeError: got unexpected keyword argument 'reporter_id__exact'
TypeError: Cannot resolve keyword 'reporter_id' into field
# You need to specify a comparison clause
>>> Article.objects.get_list(reporter_id=1)
Traceback (most recent call last):
...
TypeError: Cannot parse keyword query 'reporter_id'
# "pk" shortcut syntax works in a related context, too.
>>> Article.objects.get_list(reporter__pk=1, order_by=['pub_date'])
@ -109,4 +128,28 @@ John Smith
>>> a4.get_reporter()
John Smith
# Reporters can be queried
>>> Reporter.objects.get_list(id__exact=1)
[John Smith]
>>> Reporter.objects.get_list(pk=1)
[John Smith]
>>> Reporter.objects.get_list(first_name__startswith='John')
[John Smith]
# Reporters can query in opposite direction of ForeignKey definition
>>> Reporter.objects.get_list(articles__id__exact=1)
[John Smith]
>>> Reporter.objects.get_list(articles__pk=1)
[John Smith]
>>> Reporter.objects.get_list(articles__headline__startswith='This')
[John Smith, John Smith, John Smith]
>>> Reporter.objects.get_list(articles__headline__startswith='This', distinct=True)
[John Smith]
# Queries can go round in circles.
>>> Reporter.objects.get_list(articles__reporter__first_name__startswith='John')
[John Smith, John Smith, John Smith, John Smith]
>>> Reporter.objects.get_list(articles__reporter__first_name__startswith='John', distinct=True)
[John Smith]
"""

28
tests/modeltests/one_to_one/models.py
View File

@ -66,10 +66,23 @@ DoesNotExist: Restaurant does not exist for {'place__id__exact': ...}
>>> Restaurant.objects.get_object(place__id__exact=1)
Demon Dogs the restaurant
>>> Restaurant.objects.get_object(place__name__startswith="Demon")
Demon Dogs the restaurant
>>> Restaurant.objects.get_object(pk=1)
Demon Dogs the restaurant
>>> Restaurant.objects.get_object(place__exact=1)
Demon Dogs the restaurant
>>> Restaurant.objects.get_object(place__pk=1)
Demon Dogs the restaurant
>>> Restaurant.objects.get_object(place__name__startswith="Demon")
Demon Dogs the restaurant
>>> Place.objects.get_object(id__exact=1)
Demon Dogs the place
>>> Place.objects.get_object(pk=1)
Demon Dogs the place
>>> Place.objects.get_object(restaurants__place__exact=1)
Demon Dogs the place
>>> Place.objects.get_object(restaurants__pk=1)
Demon Dogs the place
# Add a Waiter to the Restaurant.
>>> w = r.add_waiter(name='Joe')
@ -77,6 +90,17 @@ Demon Dogs the restaurant
>>> w
Joe the waiter at Demon Dogs the restaurant
# Query the waiters
>>> Waiter.objects.get_list(restaurant__place__exact=1)
[Joe the waiter at Demon Dogs the restaurant]
>>> Waiter.objects.get_list(restaurant__pk=1)
[Joe the waiter at Demon Dogs the restaurant]
>>> Waiter.objects.get_list(id__exact=1)
[Joe the waiter at Demon Dogs the restaurant]
>>> Waiter.objects.get_list(pk=1)
[Joe the waiter at Demon Dogs the restaurant]
# Delete the restaurant; the waiter should also be removed
>>> r = Restaurant.objects.get_object(pk=1)
>>> r.delete()
"""