def check_create_fk(self, from_table_id, to_table_id, ignoreexisting=False):
from_type = setobject_type_registry.lookup_by_table(from_table_id)
to_type = setobject_type_registry.lookup_by_table(to_table_id)
pk = to_type.get_primary_key_attr_name()
# Now add foreign key if not existant yet
if not field_exists(from_table_id, self.foreignkeycol):
col = Column(
self.foreignkeycol,
getattr(to_type.get_table_class().c, pk).type,
ForeignKey(to_table_id + "." + pk),
)
col.create(from_type.get_table_class())
# The foreign key column has been newly created
Session().flush()
# deferred import
from p2.datashackle.core.models.mapping import map_tables
map_tables(exclude_sys_tables=True)
else:
# it exists, check whether it is what we want or something else
fkset = getattr(from_type.get_table_class().c, self.foreignkeycol).foreign_keys
if len(fkset) > 0:
for fk in fkset:
if str(fk.column) == to_table_id + "." + pk \
and ignoreexisting == True:
return # this is what we want! fine.
raise UserException("A relation with a similar Data Field Name but targetting the table '" + \
str(fk.column).split('.',1)[0] + "' already exists. Please use another Data Field Name.")
raise UserException("The column '" + self.foreignkeycol + "' in the table '" + to_table_id + \
"' does already exist. Please choose a unique Data Field Name that doesn't collide with existing data columns.")
def _create_adjacency_list_relation(self):
if not field_exists(self.target_table, self.foreignkeycol):
target = setobject_type_registry.lookup_by_table(self.target_table)
pk = target.get_primary_key_attr_name()
col = Column(
self.foreignkeycol,
getattr(target.get_table_class().c, pk).type,
ForeignKey(self.target_table + "." + pk),
)
col.create(target.get_table_class())
# update session and remap table
#Session().flush()
# re-map user tables with newly created linkage
from p2.datashackle.core.models.mapping import map_tables
map_tables(exclude_sys_tables=True)
def create_basemodel_type(class_name, table_name, do_mapping=True):
"""Create a setobject derived ORM type at runtime."""
# The third parameter of builtin function 'type' is a dictionary which becomes the class' __dict__. We define the __init__
# function that gets called whenever the setobject type is instantiated and its purpose is to call the
# base class' (ModelBase) __init__ function.
setobject_type = type(class_name, (ModelBase, ), {'__init__': lambda x: super(setobject_type, x).__init__()})
setobject_type.table_name = table_name
# Register setobject class type
setobject_type_registry.register_type(setobject_type, 1)
# map class to table
if do_mapping == True:
# deferred import
from p2.datashackle.core.models.mapping import map_tables
map_tables(exclude_sys_tables=True)
return setobject_type
