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闭包表—树状结构数据的数据库表设计
闭包表模型
闭包表（Closure Table）是一种通过空间换时间的模型，它是用一个专门的关系表（其实这也是我们推荐的归一化方式）来记录树上节点之间的层级关系以及距离。
场景
我们 基于 django orm实现一个文件树，文件夹直接可以实现无限嵌套
models
# 文件详情表（主要用于记录文件名）
class DmFileDetail(models.Model):file_name = models.CharField("文件名（文件夹名）", max_length=50)is_file = models.BooleanField("是否是文件", default=False)user_id = models.IntegerField("用户id", default=0)create_time = models.IntegerField("创建时间", default=0)update_time = models.IntegerField("创建时间", default=0)is_del = models.BooleanField("是否删除", default=False)class Meta:db_table = 'inchat_dm_file_detail'verbose_name = verbose_name_plural = u'数字人文件详情表'def __str__(self):return self.file_name# 文件关系表（主要用户记录文件之间的关联，即路径）
class DmFileRelation(models.Model):ancestor_id = models.IntegerField("祖先节点ID")descendant_id = models.IntegerField("子孙节点ID")depth = models.IntegerField("深度（层级）", db_index=True)user_id = models.IntegerField("用户id", default=0, db_index=True)is_del = models.BooleanField("是否删除", default=False)class Meta:db_table = 'inchat_dm_file_relation'index_together = ('ancestor_id', 'descendant_id')verbose_name = verbose_name_plural = u'数字人文件关系表'
| id | file_name |
|---|---|
| 1 | AAA |
| 2 | aaa.pdf |
| id | ancestor_id | descendant_id | depth |
|---|---|---|---|
| 1 | 1 | 1 | 0 |
| 2 | 2 | 2 | 0 |
| 3 | 1 | 2 | 1 |
增删改查
class DmRelationNode:"""关系节点"""NAME = "DmRelationNode"RELATION_CLIENT = DmFileRelation@classmethoddef insert_relation_node(cls, node_id, user_id, parent_id):"""插入新的关系节点"""# 自身insert_self = cls.RELATION_CLIENT(ancestor_id=parent_id,descendant_id=node_id,user_id=user_id,depth=1)insert_list = []# 获取父节点所有祖先parent_relation = cls.RELATION_CLIENT.objects.filter(descendant_id=parent_id) \.values_list('ancestor_id', 'depth')for ancestor_id, depth in parent_relation:insert_data = cls.RELATION_CLIENT(ancestor_id=ancestor_id,descendant_id=node_id,depth=depth + 1,user_id=user_id)insert_list.append(insert_data)# 插入自身insert_list.append(insert_self)logger.info('%s insert_relation_node.node_id:%s,parent_id:%s,insert_list:%s', cls.NAME, node_id, parent_id,insert_list)ret = cls.RELATION_CLIENT.objects.bulk_create(insert_list)logger.info('%s insert_relation_node.node_id:%s,parent_id:%s,ret_list:%s', cls.NAME, node_id, parent_id, ret)return ret@classmethoddef get_ancestor_relation(cls, node_id):"""获取某个节点的所有祖先节点"""arges = ['ancestor_id', 'descendant_id', 'depth']ancestor_relation_list = cls.RELATION_CLIENT.objects.filter(descendant_id=node_id, is_del=False).values(*arges)relation_map = dict()relation_dict = relation_mapfor ancestor in ancestor_relation_list:relation_dict['id'] = ancestor['ancestor_id']if ancestor['ancestor_id'] != node_id:relation_dict['children'] = {}relation_dict = relation_dict['children']return ancestor_relation_list@classmethoddef get_descendant_relation(cls, node_id):"""获取所有的子节点"""arges = ['ancestor_id', 'descendant_id', 'depth']descendant_relation_list = cls.RELATION_CLIENT.objects.filter(ancestor_id=node_id, is_del=False).values(*arges)return descendant_relation_list@classmethoddef get_direct_relation(cls, user_id):"""获取所有直系"""arges = ['ancestor_id', 'descendant_id', 'depth']direct_relation = cls.RELATION_CLIENT.objects.filter(depth=1, user_id=user_id, is_del=False).values(*arges)return direct_relation@classmethoddef get_children_node(cls, node_id):"""获取某节点的子节点"""children_node = cls.RELATION_CLIENT.objects.filter(depth=1, ancestor_id=node_id, is_del=False) \.values_list('descendant_id', flat=True)return children_node@classmethoddef remove_node(cls, node_id):"""删除节点"""logger.info('%s remove_node. node_id:%s', cls.NAME, node_id)query = Q(ancestor_id=node_id, is_del=False) | Q(descendant_id=node_id, is_del=False)res = cls.RELATION_CLIENT.objects.filter(query).update(is_del=True)logger.info('%s remove_node. node_id:%s,count:%s', cls.NAME, node_id, res)return res
以下 是一些常规的操作
class DmFileTree:"""DM文件树"""NAME = "DmFileTree"DETAIL_CLIENT = DmFileDetailRELATION_NODE_CLIENT = DmRelationNodeFILE_SAVE_DIR = 'media/dm/'@classmethoddef get_file_map(cls, user_id):"""获取用户所有文件文件名"""file_detail = cls.DETAIL_CLIENT.objects.filter(user_id=user_id).values('id', 'file_name', 'path', 'is_file')file_map = dict()for file in file_detail:file_dict = dict(id=file['id'],name=file['file_name'],is_file=file['is_file'],filePath=cls.FILE_SAVE_DIR + file['path'] + file['file_name'])file_map[file['id']] = file_dictreturn file_map@classmethoddef add_file(cls, user_id, file_name, parent_id, path='', is_file=False):"""新建文件（夹）"""kwargs = dict(file_name=file_name,path=path,is_file=is_file,user_id=user_id,create_time=get_cur_timestamp())file_obj = cls.DETAIL_CLIENT.objects.create(**kwargs)if not file_obj:logger.error('%s add_file failed. kwargs:%s', cls.NAME, kwargs)return Falseres = cls.RELATION_NODE_CLIENT.insert_relation_node(node_id=file_obj.id, user_id=user_id, parent_id=parent_id)if not res:return Falsereturn dict(id=file_obj.id, name=file_name)@classmethoddef get_file_path(cls, file_id):"""获取文件路径"""ancestor_query = cls.RELATION_NODE_CLIENT.get_ancestor_relation(file_id)ancestor = map(lambda x: x['ancestor_id'], ancestor_query)# 过滤0ancestor = list(filter(lambda x: x > 0, ancestor))# 排序ancestor.sort()path = '/'.join(map(str, ancestor))return '/' + path + '/' if path else '/'@classmethoddef get_all_files(cls, user_id):# 获取所有文件名字典file_map = cls.get_file_map(user_id)# 查询所有子目录及文件files_relation_list = cls.RELATION_NODE_CLIENT.get_direct_relation(user_id)file_info = {a['descendant_id']: file_map.get(a['descendant_id']) or {} for a in files_relation_list}tree = cls.list_to_tree(files_relation_list, file_info)return tree@classmethoddef get_child_files(cls, user_id, parent_id):"""获取下级文件"""# 获取所有文件名字典file_map = cls.get_file_map(user_id)file_list = cls.RELATION_NODE_CLIENT.get_children_node(node_id=parent_id)files = map(lambda x: dict(id=x, name=file_map.get(x) or ''), file_list)return files@staticmethoddef list_to_tree(data, node_dict):"""将节点列表转换成树形结构字典:param data: 带有 id 和 parent_id 属性的节点列表:param node_dict: 单节点的数据结构字典:return: 树形结构字典"""tree = []# 遍历每一个节点，将其添加到父节点的字典或根节点列表中for item in data:id = item['descendant_id']parent_id = item['ancestor_id']# 如果父节点为 None，则将当前节点添加到根节点列表中if not parent_id:tree.append(node_dict[id])# 如果父节点存在，则将当前节点添加到父节点的 children 属性中else:parent = node_dict[parent_id]if 'children' not in parent:parent['children'] = []parent['children'].append(node_dict[id])return tree@classmethoddef delete_file(cls, file_id):"""文件删除"""res1 = cls.DETAIL_CLIENT.objects.filter(id=file_id).update(is_del=True)logger.info('%s delete_file. file_id:%s, count:%s', cls.NAME, file_id, res1)res2 = cls.RELATION_NODE_CLIENT.remove_node(file_id)return res1, res2@classmethoddef search_file(cls, file_name):"""搜索文件"""query_set = cls.DETAIL_CLIENT.objects.filter(file_name__icontains=file_name) \.values('id', 'file_name', 'path', 'is_file')file_list = []for file in query_set:file_dict = dict(id=file['id'],name=file['file_name'],is_file=file['is_file'],filePath='media/dm_upload' + file['path'])file_list.append(file_dict)return file_list@classmethoddef get_file_url(cls, file_id, file_obj=None):"""获取文件下载链接"""file_url = ''if not file_obj:file_obj = cls.DETAIL_CLIENT.objects.filter(id=file_id).first()if file_obj:file_url = 'http://127.0.0.1:8000/' + cls.FILE_SAVE_DIR + file_obj.path + file_obj.file_namereturn file_url
除此之外，还有移动、复制文件（夹）。移动就是先删除再新增