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foreign key relatinoships are defined primarily at the schema level

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Mike Bayer
2005-09-15 02:55:16 +00:00
parent 38a965e5a6
commit a57d576397
2 changed files with 57 additions and 34 deletions
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lib/sqlalchemy/mapper.py
+52 -29
View File
@@ -36,8 +36,8 @@ def relation_loader(mapper, secondary = None, primaryjoin = None, secondaryjoin
else:
return EagerLoader(mapper, secondary, primaryjoin, secondaryjoin, **options)
def relation_mapper(class_, selectable, secondary = None, primaryjoin = None, secondaryjoin = None, table = None, properties = None, lazy = True, uselist = True, foreignkey = None, **options):
return relation_loader(mapper(class_, selectable, table = table, properties = properties, **options), secondary, primaryjoin, secondaryjoin, lazy = lazy, uselist = uselist, foreignkey = foreignkey, **options)
def relation_mapper(class_, selectable, secondary = None, primaryjoin = None, secondaryjoin = None, table = None, properties = None, lazy = True, uselist = True, foreignkey = None, primary_keys = None, **options):
return relation_loader(mapper(class_, selectable, table=table, properties=properties, primary_keys=primary_keys, **options), secondary, primaryjoin, secondaryjoin, lazy = lazy, uselist = uselist, foreignkey = foreignkey, **options)
_mappers = {}
def mapper(*args, **params):
@@ -65,7 +65,7 @@ def object_mapper(object):
raise "Object " + object.__class__.__name__ + "/" + repr(id(object)) + " has no mapper specified"
class Mapper(object):
def __init__(self, hashkey, class_, selectable, table = None, scope = "thread", properties = None, echo = None, **kwargs):
def __init__(self, hashkey, class_, selectable, table = None, scope = "thread", properties = None, echo = None, primary_keys = None, **kwargs):
self.hashkey = hashkey
self.class_ = class_
self.scope = scope
@@ -73,6 +73,7 @@ class Mapper(object):
tf = TableFinder()
self.selectable.accept_visitor(tf)
self.tables = tf.tables
self.primary_keys = {}
if table is None:
if len(self.tables) > 1:
@@ -81,6 +82,22 @@ class Mapper(object):
else:
self.table = table
if primary_keys is not None:
for k in primary_keys:
self.primary_keys.setdefault(k.table, []).append(k)
else:
for t in self.tables + [self.selectable]:
try:
list = self.primary_keys[t]
except KeyError:
list = self.primary_keys.setdefault(t, util.HashSet())
if not len(t.primary_keys):
raise "Table " + t.name + " has no primary keys. Specify primary_keys argument to mapper."
for k in t.primary_keys:
list.append(k)
self.echo = echo
# object attribute names mapped to MapperProperty objects
@@ -152,13 +169,13 @@ class Mapper(object):
"""returns an instance of the object based on the given identifier, or None
if not found. The *ident argument is a
list of primary keys in the order of the table def's primary keys."""
key = objectstore.get_id_key(ident, self.class_, self.table, self.selectable)
key = objectstore.get_id_key(ident, self.class_, self.table)
try:
return objectstore.get(key)
except KeyError:
clause = sql.and_()
i = 0
for primary_key in self.table.primary_keys:
for primary_key in self.primary_keys[table]:
# appending to the and_'s clause list directly to skip
# typechecks etc.
clause.clauses.append(primary_key == ident[i])
@@ -169,7 +186,7 @@ class Mapper(object):
return None
def put(self, instance):
key = objectstore.get_instance_key(instance, self.class_, self.table, self.selectable)
key = objectstore.get_instance_key(instance, self.class_, self.table, self.primary_keys[self.selectable])
objectstore.put(key, instance, self.scope)
return key
@@ -232,7 +249,7 @@ class Mapper(object):
for table, stuff in work.iteritems():
if len(stuff['update']):
clause = sql.and_()
for col in table.primary_keys:
for col in self.primary_keys[table]:
clause.clauses.append(col == sql.bindparam(col.key))
statement = table.update(clause)
statement.echo = self.echo
@@ -246,7 +263,7 @@ class Mapper(object):
statement.execute(**params)
primary_key = table.engine.last_inserted_ids()[0]
found = False
for col in table.primary_keys:
for col in self.primary_keys[table]:
if self._getattrbycolumn(obj, col) is None:
if found:
raise "Only one primary key per inserted row can be set via autoincrement/sequence"
@@ -282,7 +299,7 @@ class Mapper(object):
return self.instances(statement.execute(**params))
def _identity_key(self, row):
return objectstore.get_row_key(row, self.class_, self.table, self.selectable)
return objectstore.get_row_key(row, self.class_, self.table, self.primary_keys[self.selectable])
def _instance(self, row, result = None):
"""pulls an object instance from the given row and appends it to the given result list.
@@ -297,7 +314,7 @@ class Mapper(object):
if not exists:
instance = self.class_()
instance._mapper = self.hashkey
for column in self.selectable.primary_keys:
for column in self.primary_keys[self.selectable]:
if row[column.label] is None:
return None
objectstore.put(identitykey, instance, self.scope)
@@ -408,23 +425,20 @@ class PropertyLoader(MapperProperty):
self.primaryjoin = self.match_primaries(parent.selectable, self.secondary)
else:
if self.primaryjoin is None:
if self.foreignkey is not None and self.foreignkey.table == parent.selectable:
self.primaryjoin = self.match_primaries(self.target, parent.selectable)
else:
self.primaryjoin = self.match_primaries(parent.selectable, self.target)
self.primaryjoin = self.match_primaries(parent.selectable, self.target)
# if the foreign key wasnt specified and theres no assocaition table, try to figure
# out who is dependent on who. we dont need all the foreign keys represented in the join,
# just one of them.
if self.foreignkey is None and self.secondaryjoin is None:
# if self.foreignkey is None and self.secondaryjoin is None:
# else we usually will have a one-to-many where the secondary depends on the primary
# but its possible that its reversed
w = PropertyLoader.FindDependent()
self.primaryjoin.accept_visitor(w)
if w.dependent is None:
raise "cant determine primary foreign key in the join relationship....specify foreignkey=<column>"
else:
self.foreignkey = w.dependent
# w = PropertyLoader.FindDependent()
# self.primaryjoin.accept_visitor(w)
# if w.dependent is None:
# raise "cant determine primary foreign key in the join relationship....specify foreignkey=<column>"
# else:
# self.foreignkey = w.dependent
if not hasattr(parent.class_, key):
setattr(parent.class_, key, SmartProperty(key).property(usehistory = True, uselist = self.uselist))
@@ -445,14 +459,23 @@ class PropertyLoader(MapperProperty):
def match_primaries(self, primary, secondary):
pk = primary.primary_keys
try:
if len(pk) == 1:
return (pk[0] == secondary.c[pk[0].name])
else:
return sql.and_([pk == secondary.c[pk.name] for pk in primary.primary_keys])
except AttributeError, e:
raise e.args[0] + " table: " + secondary.name
crit = []
for fk in secondary.foreign_keys:
if fk.column.table is primary:
crit.append(fk.column == fk.parent)
self.foreignkey = fk.parent
for fk in primary.foreign_keys:
if fk.column.table is secondary:
crit.append(fk.column == fk.parent)
self.foreignkey = fk.parent
if len(crit) == 0:
raise "Cant find any foreign key relationships between " + primary.table.name + " and " + secondary.table.name
elif len(crit) == 1:
return (crit[0])
else:
return sql.and_(crit)
def register_dependencies(self, objlist, uow):
if self.secondaryjoin is not None:
lib/sqlalchemy/objectstore.py
+5 -5
View File
@@ -24,7 +24,7 @@ import thread
import sqlalchemy.util as util
import weakref
def get_id_key(ident, class_, table, selectable):
def get_id_key(ident, class_, table):
"""returns an identity-map key for use in storing/retrieving an item from the identity map, given
a tuple of the object's primary key values.
@@ -37,7 +37,7 @@ def get_id_key(ident, class_, table, selectable):
return value: a tuple object which is used as an identity key.
"""
return (class_, table, tuple(ident))
def get_instance_key(object, class_, table, selectable):
def get_instance_key(object, class_, table, primary_keys):
"""returns an identity-map key for use in storing/retrieving an item from the identity map, given
the object instance itself.
@@ -49,8 +49,8 @@ def get_instance_key(object, class_, table, selectable):
may be synonymous with the table argument or can be a larger construct containing that table.
return value: a tuple object which is used as an identity key.
"""
return (class_, table, tuple([getattr(object, column.key, None) for column in selectable.primary_keys]))
def get_row_key(row, class_, table, selectable):
return (class_, table, tuple([getattr(object, column.key, None) for column in primary_keys]))
def get_row_key(row, class_, table, primary_keys):
"""returns an identity-map key for use in storing/retrieving an item from the identity map, given
a result set row.
@@ -62,7 +62,7 @@ def get_row_key(row, class_, table, selectable):
may be synonymous with the table argument or can be a larger construct containing that table.
return value: a tuple object which is used as an identity key.
"""
return (class_, table, tuple([row[column.label] for column in selectable.primary_keys]))
return (class_, table, tuple([row[column.label] for column in primary_keys]))
identity_map = {}