为什么我的数据库在将数据添加到另一个数据库时变空？

Question

当我尝试将数据添加到我的 images.db 数据库时，我有两个数据库连接到我的 Flask 服务器，来自 users.db 的数据被自动删除。之前两个表都在同一个数据库中，但是现在即使创建了两个单独的数据库，问题也没有解决。

这是 models.py

的代码

class Image(db.Model): #images.db
    id = db.Column(db.Integer, primary_key=True)
    date_observed = db.Column(db.DateTime, unique=True, nullable=False)
    jd = db.Column(db.Float, unique=True, nullable=False)

    def __repr__(self):
        attrs = vars(self)
        return ', '.join("%s: %s" % item for item in attrs.items())
    

# User table in the database
class User(db.Model, UserMixin):
    __bind_key__ = 'users'
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(20), unique=True, nullable=False)
    email = db.Column(db.String(120), unique=True, nullable=False)
    password = db.Column(db.String(60), nullable=False)
    history = db.Column(db.String(240))

    def __repr__(self):
        return "User({self.username}, {self.email})".format()

def file_to_Image_obj(fits_image_filename):
    
    hdul = fits.open(fits_image_filename)
    hdr = hdul[0].header
    (y_end,x_end) = hdul[0].data.shape 
    hdul.close()
    wcs = WCS(hdr)
    
    n_of_div = 5

    this_image = Image(
    date_observed = parse(read_header('DATE-OBS',hdr)),
    jd = read_header('JD',hdr)
)
    
    return this_image

# takes as input directory path and adds all fits files (.fits extension) to the db
def add_dir_to_db(dirpath, append=True):
    print('Adding Images to Database')
    if not append:
        db.drop_all()
        db.create_all()
    
    for dirpath, dirnames, filenames in os.walk(dirpath):
        for filename in filenames:
            filepath = os.path.join(dirpath, filename)
            #changed to proc.fits for demo
            if filepath.endswith('.fits'):
                try :
                    this_image = file_to_Image_obj(filepath)
                    print(filepath, this_image.date_observed)
                    db.session.add(this_image)
                except Exception as e :
                    with open("error_report.txt","a") as logf:
                        logf.write("Failed to make db object {0}: {1}\n".format(filepath, str(e)))
                    print (str(e))
                
                
    db.session.commit()

def add_user_to_db(username, email, password):
    print('Adding User')
    user = User(username=username, email=email, password=password)
    db.session.add(user)
    db.session.commit()

Answer 1

更新：找到问题的答案。函数 add_dir_to_db() 有 db.drop_all() 没有任何绑定键集。对于默认数据库，我只需要设置 bind_key = None

def add_dir_to_db(dirpath, append=True):
    print('Adding Images to Database')
    if not append:
        db.drop_all(bind_key=None)
        db.create_all(bind_key=None)

为什么我的数据库在将数据添加到另一个数据库时变空？

Why does my database gets empty on adding data to another database?

database

sqlite

web-deployment

flask

flask-sqlalchemy