我有一个现有的数据库,其中包含两个模式,分别命名为schools
和students
,这些模式包含在一个declarative_base
实例中,并通过两个不同的类继承自该实例。
class DirectorioEstablecimiento(Base):
__table_args__ = {'schema': 'schools'}
__tablename__ = 'addresses'
# some Columns are defined here
并且
class Matricula(Base):
__table_args__ = {'schema': 'students'}
__tablename__ = 'enrollments'
# some Columns are defined here
我可以使用Base
实例作为Base.metadata.create_all(bind=engine)
在我的postgres测试数据库中重新创建它。如果我查询pg_namespace
,我可以确认这一点已经完成了。
In [111]: engine.execute("SELECT * FROM pg_namespace").fetchall()
2017-12-13 18:04:01,006 INFO sqlalchemy.engine.base.Engine SELECT * FROM pg_namespace
2017-12-13 18:04:01,006 INFO sqlalchemy.engine.base.Engine {}
Out[111]:
[('pg_toast', 10, None),
('pg_temp_1', 10, None),
('pg_toast_temp_1', 10, None),
('pg_catalog', 10, '{postgres=UC/postgres,=U/postgres}'),
('public', 10, '{postgres=UC/postgres,=UC/postgres}'),
('information_schema', 10, '{postgres=UC/postgres,=U/postgres}'),
('schools', 16386, None),
('students', 16386, None)]
并且从psql命令行界面执行
user# select * from pg_tables;
schemaname | tablename | tableowner | tablespace | hasindexes | hasrules | hastriggers | rowsecurity
--------------------+------------------------------+------------+------------+------------+----------+-------------+-------------
schools | addresses | diego | | t | f | f | f
students | enrollments | diego | | t | f | f | f
pg_catalog | pg_statistic | postgres | | t | f | f | f
pg_catalog | pg_type | postgres | | t | f | f | f
pg_catalog | pg_authid | postgres | pg_global | t | f | f | f
pg_catalog | pg_user_mapping | postgres | | t | f | f | f
-- other tables were omitted
然而,如果我想在declarative_base
的其他实例中反映该数据库,就无法反映出来。
类似如下:
In [87]: Base.metadata.tables.keys()
Out[87]: dict_keys(['schools.addresses', 'students.enrollments'])
In [88]: new_base = declarative_base()
In [89]: new_base.metadata.reflect(bind=engine)
In [90]: new_base.metadata.tables.keys()
Out[90]: dict_keys([])
我知道
reflect
可以接受一个schema
作为参数,但我希望在反射过程中一次性获取所有schema
。不知何故,我只能逐个获取它们。有没有办法做到这一点?