Question

在下面，可执行源代码我有一个小问题。那么你可以看到，我在名为nullable的列中将some_text设置为False。当我运行这个程序时，正确输入所有必要的注册数据，并在我应该输入文本的地方，但我只是按输入，我没有收到任何错误信息。我想，当我按下回车键（没有文字，空项目）时，我会收到来自SQLAlchemy的错误信息。但什么都没发生。 SQLAlchemy只执行commit ()。之后，当我使用MySQL WorkBench时，数据库中会出现一个空条目。

我做错了吗？

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import create_engine
from sqlalchemy.exc import SQLAlchemyError
from sqlalchemy.orm import sessionmaker
from sqlalchemy import Table, Column, Integer, String

''' setting up root class for declarative declaration '''
Base = declarative_base()

class SOME_TEXT(Base):

    __tablename__ = "some_text"

    id = Column(Integer, primary_key=True, unique=True)
    some_text = Column(String(50), nullable=False, unique=True)

    def __init__(self, Some_text):

        self.some_text = Some_text

def main():
    try:
        dbms = raw_input('Enter database type: ')
        dbdriver = raw_input('Enter database driver: ')
        dbuser = raw_input('Enter user name: ')
        dbuser_pwd = raw_input('Enter user password: ')
        db_server_host = raw_input('Enter server host: ')
        dbport = raw_input('Enter port: ')
        db_name = raw_input('Enter database name: ')

        url = '{}+{}://{}:{}@{}:{}/{}'.format(
               dbms, dbdriver, dbuser, dbuser_pwd, db_server_host, dbport, db_name)

        ''' Create the engine '''
        engine = create_engine(url, echo=True)

        ''' Create the schema and tables '''
        Base.metadata.create_all(engine)

        ''' Create the Session class '''
        Session = sessionmaker(bind=engine)

        ''' Create a new Session '''
        session = Session()

        ''' Populate the database '''
        enter_text = raw_input('Enter text: ')
        some_text_table = SOME_TEXT(enter_text)
        session.add(some_text_table)

        ''' Commit the changes: '''
        session.commit()

    except SQLAlchemyError as err:
        print "err", err


if __name__ == "__main__":
    main()

SQL Alchemy：如何使用NOT NULL子句

0 个答案: