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flask-SQLAlchemy create_all()

当我运行dbManager时。create_all()命令,它运行时出现错误,但无法创建表。 当我删除数据库并运行create_all()命令时,我得到没有这样的数据库作为#####错误,我应该得到,但是当数据库确实存在时,没有任何反应。 请任何人都可以看到我做错了什么?

from blogconfig import dbManager


class Art(dbManager.Model):
    id = dbManager.Column(dbManager.Integer, primary_key = True)
    title = dbManager.Column(dbManager.String(64), index = True, unique = True)
    content = dbManager.Column(dbManager.Text(5000))




    def __repr__(self):
        return '<Art %r>' %(self.title)

编辑 这是shell命令

from blogconfig import dbManager
>>> dbManager.create_all()



 import models

>>> a = models.Art(title='des', content='asdfvhbdjbjdn')
>>> dbManager.session.add(a)
>>> dbManager.session.commit()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/scoping.py", line 149, in do
    return getattr(self.registry(), name)(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 721, in commit
    self.transaction.commit()
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 354, in commit
    self._prepare_impl()
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 334, in _prepare_impl
    self.session.flush()
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 1818, in flush
    self._flush(objects)
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 1936, in _flush
    transaction.rollback(_capture_exception=True)
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/util/langhelpers.py", line 58, in __exit__
    compat.reraise(exc_type, exc_value, exc_tb)
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 1900, in _flush
    flush_context.execute()
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/unitofwork.py", line 372, in execute
    rec.execute(self)
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/unitofwork.py", line 525, in execute
    uow
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/persistence.py", line 64, in save_obj
    table, insert)
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/persistence.py", line 569, in _emit_insert_statements
    execute(statement, params)
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 662, in execute
    params)
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 761, in _execute_clauseelement
    compiled_sql, distilled_params
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 874, in _execute_context
    context)
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1024, in _handle_dbapi_exception
    exc_info
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/util/compat.py", line 195, in raise_from_cause
    reraise(type(exception), exception, tb=exc_tb)
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 867, in _execute_context
    context)
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/default.py", line 324, in do_execute
    cursor.execute(statement, parameters)
  File "/usr/lib/python2.7/dist-packages/MySQLdb/cursors.py", line 174, in execute
    self.errorhandler(self, exc, value)
  File "/usr/lib/python2.7/dist-packages/MySQLdb/connections.py", line 36, in defaulterrorhandler
    raise errorclass, errorvalue
sqlalchemy.exc.ProgrammingError: (ProgrammingError) (1146, "Table 'blog.art' doesn't exist") 'INSERT INTO art (title, content) VALUES (%s, %s)' ('des', 'asdfvhbdjbjdn')
原网址
A:

dbManager不会知道您在其他模块中定义的模型,除非它们在运行create_all之前被导入。

在实际应用中,这应该无关紧要,因为运行flask应用程序应该设置数据库并导入视图/蓝图以注册它们。 由于视图使用模型,因此模型是间接导入的,并且可供dbManager使用。

在创建dbManager实例后在blogconfig模块中导入模型,或者将shell命令的顺序更改为

>>> from blogconfig import dbManager
>>> import models
>>> dbManager.create_all()

SQLAlchemy只会创建表,数据库必须已经存在,这就是为什么您在删除数据库时看到其他错误的原因。

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