class DBDB(object):
'''
defines a class (DBDB) which implements the Python dictionary API using the concrete BinaryTree implementation. This is how you'd use DBDB inside a Python program.
'''
def __init__(self, f):
self._storage = Storage(f)
self._tree = BinaryTree(self._storage)
def _assert_not_closed(self):
if self._storage.closed:
raise ValueError('Database closed.')
def __getitem__(self, key):
self._assert_not_closed()
return self._tree.get(key)
def __setitem__(self, key, value):
self._assert_not_closed()
return self._tree.set(key, value)
def __delitem__(self, key):
self._assert_not_closed()
return self._tree.pop(key)
def __contains__(self, key):
try:
self[key]
except KeyError:
return False
else:
return True
def close(self):
self._storage.close()
def commit(self):
self._assert_not_closed()
self._tree.commit()
def __len__(self):
return len(self._tree)
def find_max(self):
return self._tree.find_max()
class DBDB(object):
'''
defines a class (DBDB) which implements the Python dictionary API using the concrete BinaryTree implementation. This is how you'd use DBDB inside a Python program.
'''
def __init__(self, f):
self._storage = Storage(f)
self._tree = BinaryTree(self._storage)
def _assert_not_closed(self):
if self._storage.closed:
raise ValueError('Database closed.')
def __getitem__(self, key):
self._assert_not_closed()
return self._tree.get(key)
def __setitem__(self, key, value):
self._assert_not_closed()
return self._tree.set(key, value)
def __delitem__(self, key):
self._assert_not_closed()
return self._tree.pop(key)
def __contains__(self, key):
try:
self[key]
except KeyError:
return False
else:
return True
def close(self):
self._storage.close()
def commit(self):
self._assert_not_closed()
self._tree.commit()
def __len__(self):
return len(self._tree)
def find_max(self):
return self._tree.find_max()
class DBDB(object):
"""
implements the python dictionary API using the concrete BinaryTree implementation
"""
def __init__(self, f):
self._storage = Storage(f)
# Data stores tend to use more complex types of search trees such as
# B-trees, B+ trees, and others to improve the performance.
self._tree = BinaryTree(self._storage)
def _assert_not_closed(self):
if self._storage.closed:
raise ValueError('Database closed!')
def commit(self):
self._assert_not_closed()
self._tree.commit()
def close(self):
self._storage.close()
def __getitem__(self, key):
self._assert_not_closed()
return self._tree.get(key)
def __setitem__(self, key, value):
self._assert_not_closed()
return self._tree.set(key, value)
def __delitem__(self, key):
self._assert_not_closed()
return self._tree.pop(key)
def __contains__(self, key):
try:
self[key]
except KeyError:
return False
else:
return True
def __len__(self):
return len(self._tree)
class DB(object):
"""将二叉树的操作封装成dict键值对操作"""
def __init__(self, f):
self._storage = Storage(f)
self._tree = BinaryTree(self._storage)
def _assert_not_closed(self):
"""检查文件是否关闭"""
if self._storage.closed:
raise ValueError('Database closed.')
def close(self):
self._storage.close()
def commit(self):
"""提交后才会更新数据库"""
self._assert_not_closed()
self._tree.commit()
def __getitem__(self, key):
"""通过 db[key] 获取值"""
pass
def __setitem__(self, key, value):
"""通过 db[key] = value 设置值"""
pass
def __delitem__(self, key):
"""通过 del db[key] 删除值"""
pass
def __contains__(self, key):
"""通过 key in db 判断键是否在数据库"""
try:
self[key]
except KeyError:
return False
else:
return True
def __len__(self):
return len(self._tree)
class DBDB(object):
def __init__(self, f):
self._storage = Storage(f)
self._tree = BinaryTree(self._storage)
def _assert_not_closed(self):
if self._storage.closed:
raise ValueError('Database closed.')
def close(self):
self._storage.close()
def commit(self):
self._assert_not_closed()
self._tree.commit()
def __getitem__(self, key):
self._assert_not_closed()
return self._tree.get(key)
def __setitem__(self, key, value):
self._assert_not_closed()
return self._tree.set(key, value)
def __delitem__(self, key):
self._assert_not_closed()
return self._tree.pop(key)
def __contains__(self, key):
try:
self[key]
except KeyError:
return False
else:
return True
def __len__(self):
return len(self._tree)
