def update(self, item):
item_id = self._get_column_value(item, self._id_column)
item_name = self._get_column_value(item, self._name_column)
if not item_id:
msg = 'Cannot update %s with no id' % self._type_name
raise ValueError(msg)
if not item_id in self._by_id:
msg = 'Cannot update non-existent %s with id %s'
msg = msg % (self._type_name, item_id)
raise ValueError(msg)
old_item_name = self._by_id[item_id].name
values = dict((x, self._get_column_value(item, x)) \
for x in self._columns[1:])
id_criteria = { self._id_column : item_id }
execute_update(self._db, self._table_name, values, id_criteria)
with execute_select(self._db, self._table_name, self._columns,
id_criteria, self._create_item) as results:
new_item = next(results)
for (n, item) in enumerate(self._all):
if self._get_column_value(item, self._id_column) == item_id:
self._all[n] = new_item
break
self._by_id[item_id] = new_item
if item_name != old_item_name:
del self._by_name[old_item_name]
self._by_name[item_name] = new_item
def add(self, item):
item_id = self._get_column_value(item, self._id_column)
item_name = self._get_column_value(item, self._name_column)
if item_id:
msg = '%s with id %s already exists' % (self._type_name, item_id)
raise ValueError(msg)
if item_name in self._by_name:
print [repr(x) for x in self._by_name]
msg = '%s with name "%s" already exists' % (self._type_name,
item_name)
raise ValueError(msg)
values = dict((x, self._get_column_value(item, x)) \
for x in self._columns[1:])
item_id = next_item_id(self._db, self._table_name)
values[self._id_column] = item_id
execute_insert(self._db, self._table_name, values)
with execute_select(self._db, self._table_name, self._columns,
{ self._id_column : item_id },
self._create_item) as results:
new_item = next(results)
self._all.append(new_item)
self._by_id[item_id] = new_item
item_name = self._get_column_value(new_item, self._name_column)
self._by_name[item_name] = new_item
return new_item
def with_id(self, id):
with execute_select(self._db, self._table_name, self._columns,
{ self._id_column : id },
self._create_item) as results:
try:
return next(results)
except StopIteration:
return None
def __init__(self, type_name, db, table_name, columns, item_constructor,
column_value_extractor):
def id_for(x):
return self._get_column_value(x, columns[0])
def name_for(x):
return self._get_column_value(x, columns[1])
self._type_name = type_name
self._db = db
self._table_name = table_name
self._columns = columns
self._id_column = columns[0]
self._name_column = columns[1]
self._create_item = item_constructor
self._get_column_value = column_value_extractor
with execute_select(db, table_name, columns, { },
item_constructor) as results:
self._all = [ x for x in results ]
self._by_id = dict((id_for(x), x) for x in self._all)
self._by_name = dict((name_for(x), x) for x in self._all)
def retrieve(self, **criteria):
return execute_select(self._db, self._table_name, self._columns,
self._normalize_criteria(criteria),
self._create_item)
def all(self):
with execute_select(self._db, self._table_name, self._columns, { },
self._create_item) as items:
return [ x for x in items ]