Python sqlalchemy，如果不存在则创建一个sqlite数据库
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sqlalchemy,creating an sqlite database if it doesn't exist
提问by Gandalf
I am trying out sqlalchemy and i am using this connection string to connect to my databases
我正在尝试 sqlalchemy 并且我正在使用此连接字符串连接到我的数据库
engine = create_engine('sqlite:///C:\sqlitedbs\database.db')
Does sqlalchemy create an sqlite database for you if one is not already present in a directory it was supposed to fetch the database file?.
sqlalchemy 是否会为您创建一个 sqlite 数据库，如果它不存在于它应该获取数据库文件的目录中？。
采纳答案by Gandalf
Yes,sqlalchemy does create a database for you.I confirmed it on windows using this code
是的，sqlalchemy 确实为您创建了一个数据库。我使用此代码在 Windows 上确认了它
from sqlalchemy import create_engine, ForeignKey
from sqlalchemy import Column, Date, Integer, String
from sqlalchemy.ext.declarative import declarative_base
engine = create_engine('sqlite:///C:\sqlitedbs\school.db', echo=True)
Base = declarative_base()
class School(Base):
__tablename__ = "woot"
id = Column(Integer, primary_key=True)
name = Column(String)
def __init__(self, name):
self.name = name
Base.metadata.create_all(engine)
回答by danio
I found (using sqlite+pysqlite) that if the directory exists, it will create it, but if the directory does not exist it throws an exception:
我发现（使用 sqlite+pysqlite）如果目录存在，它会创建它，但如果目录不存在，它会抛出异常：
OperationalError: (sqlite3.OperationalError) unable to open database file
My workaround is to do this, although it feels nasty:
我的解决方法是这样做，虽然感觉很讨厌：
if connection_string.startswith('sqlite'):
db_file = re.sub("sqlite.*:///", "", connection_string)
os.makedirs(os.path.dirname(db_file), exist_ok=True)
self.engine = sqlalchemy.create_engine(connection_string)
