Question

我正在尝试使用Flask_SQLAlchemy在我的app.config['SQLALCHEMY_DATABASE_URI']

中映射一个外部数据库

外部数据库是用户输入，因此我无法猜测每个用户的数据库结构

我已允许

在用户数据库和我的系统之间建立连接

@app.route('/test')
def test():
    engine = db.create_engine(USER_DB)
    Session = db.sessionmaker(bind=engine)
    session = db.scoped_session(engine) 

#after that i was able to get the table name's and structure using 

    x = {table:db.Table(table,db.metadata,autoload=True,autoload_with=engine)
                 for table in engine.table_names()}
    print(f'\n\n x  = {x} \n\n')
    findme = session.query(test1.filter_by(id=1).first())

控制台：

x = {'test1': Table('test1', MetaData(bind=None), Column('id', INTEGER(), table=<test1>, nullable=False, server_default=DefaultClause(<sqlalchemy.sql.elements.TextClause object at 0x000001F83BCAEC50>, for_update=False)), Column('name', VARCHAR(), table=<test1>, nullable=False), schema=None), 'test2': Table('test2', MetaData(bind=None), Column('id2', INTEGER(), table=<test2>, nullable=False, server_default=DefaultClause(<sqlalchemy.sql.elements.TextClause object at 0x000001F83BCCEA58>, for_update=False)), Column('name2', VARCHAR(length=200), table=<test2>, nullable=False), schema=None)}

您可以看到它可以读取其中的列的结构

然后其余的输出：

（追溯）

    Traceback (most recent call last):
  File "C:\ProgramData\Anaconda3\lib\site-packages\flask\app.py", line 1997, in __call__
    return self.wsgi_app(environ, start_response)
  File "C:\ProgramData\Anaconda3\lib\site-packages\flask\app.py", line 1985, in wsgi_app
    response = self.handle_exception(e)
  File "C:\ProgramData\Anaconda3\lib\site-packages\flask\app.py", line 1540, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "C:\ProgramData\Anaconda3\lib\site-packages\flask\_compat.py", line 33, in reraise
    raise value
  File "C:\ProgramData\Anaconda3\lib\site-packages\flask\app.py", line 1982, in wsgi_app
    response = self.full_dispatch_request()
  File "C:\ProgramData\Anaconda3\lib\site-packages\flask\app.py", line 1614, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "C:\ProgramData\Anaconda3\lib\site-packages\flask\app.py", line 1517, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "C:\ProgramData\Anaconda3\lib\site-packages\flask\_compat.py", line 33, in reraise
    raise value
  File "C:\ProgramData\Anaconda3\lib\site-packages\flask\app.py", line 1612, in full_dispatch_request
    rv = self.dispatch_request()
  File "C:\ProgramData\Anaconda3\lib\site-packages\flask\app.py", line 1598, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "D:\app1\app.py", line 181, in test
    cc = session.query(test1.filter_by(id=1).first())
NameError: name 'test1' is not defined

如何允许 SQLALCHEMY 自动定义结构？有那些

*自动映射/反射/ python包“ sqlacodegen” * 在这种情况下很有用，如果可以，我如何从中受益？

Flask_SQLAlchemy读取新数据库

0 个答案: