基本上，在 models.py 中的 Flask 应用服务器上，您使用类在 PostgreSQL 上调用 ORM，但是如果您执行一对一关系或一对多关系。如果您没有将密钥定义为“唯一”，您可能会收到错误消息。在postgresql中，所有外键必须引用父表中的唯一键，因此在您的bar表中，您必须有一个唯一（名称）索引。最后，我们应该提到外键必须引用主键或表单的列唯一的约束。
Traceback (most recent call last):
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\sqlalchemy\engine\base.py", line 1248, in _execute_context
cursor, statement, parameters, context
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\sqlalchemy\engine\default.py", line 588, in do_execute
cursor.execute(statement, parameters)
psycopg2.errors.InvalidForeignKey: there is no unique constraint matching given keys for referenced table "dicom"
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "C:\Users\lesli\AppData\Local\Programs\Python\Python37\lib\runpy.py", line 193, in _run_module_as_main
"__main__", mod_spec)
File "C:\Users\lesli\AppData\Local\Programs\Python\Python37\lib\runpy.py", line 85, in _run_code
exec(code, run_globals)
File "D:\L_pipe\vessel_app_celery\vessel_env\Scripts\flask.exe\__main__.py", line 9, in <module>
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\flask\cli.py", line 990, in main
cli.main(args=sys.argv[1:])
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\flask\cli.py", line 596, in main
return super().main(*args, **kwargs)
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\click\core.py", line 1062, in main
rv = self.invoke(ctx)
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\click\core.py", line 1668, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\click\core.py", line 1668, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\click\core.py", line 1404, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\click\core.py", line 763, in invoke
return __callback(*args, **kwargs)
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\click\decorators.py", line 26, in new_func
return f(get_current_context(), *args, **kwargs)
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\flask\cli.py", line 440, in decorator
return __ctx.invoke(f, *args, **kwargs)
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\click\core.py", line 763, in invoke
return __callback(*args, **kwargs)
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\flask_migrate\cli.py", line 134, in upgrade
_upgrade(directory, revision, sql, tag, x_arg)
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\flask_migrate\__init__.py", line 95, in wrapped
f(*args, **kwargs)
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\flask_migrate\__init__.py", line 280, in upgrade
command.upgrade(config, revision, sql=sql, tag=tag)
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\alembic\command.py", line 298, in upgrade
script.run_env()
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\alembic\script\base.py", line 489, in run_env
util.load_python_file(self.dir, "env.py")
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\alembic\util\pyfiles.py", line 98, in load_python_file
module = load_module_py(module_id, path)
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\alembic\util\compat.py", line 184, in load_module_py
spec.loader.exec_module(module)
File "<frozen importlib._bootstrap_external>", line 728, in exec_module
File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
File "migrations\env.py", line 96, in <module>
run_migrations_online()
File "migrations\env.py", line 90, in run_migrations_online
context.run_migrations()
File "<string>", line 8, in run_migrations
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\alembic\runtime\environment.py", line 846, in run_migrations
self.get_context().run_migrations(**kw)
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\alembic\runtime\migration.py", line 520, in run_migrations
step.migration_fn(**kw)
File "D:\L_pipe\vessel_app_celery\Vessel-app\Back-end\migrations\versions\9ea0138f3052_.py", line 228, in upgrade
sa.PrimaryKeyConstraint('id')
File "<string>", line 8, in create_table
File "<string>", line 3, in create_table
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\alembic\operations\ops.py", line 1252, in create_table
return operations.invoke(op)
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\alembic\operations\base.py", line 374, in invoke
return fn(self, operation)
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\alembic\operations\toimpl.py", line 101, in create_table
operations.impl.create_table(table)
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\alembic\ddl\impl.py", line 258, in create_table
self._exec(schema.CreateTable(table))
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\alembic\ddl\impl.py", line 140, in _exec
return conn.execute(construct, *multiparams, **params)
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\sqlalchemy\engine\base.py", line 984, in execute
return meth(self, multiparams, params)
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\sqlalchemy\sql\ddl.py", line 72, in _execute_on_connection
return connection._execute_ddl(self, multiparams, params)
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\sqlalchemy\engine\base.py", line 1046, in _execute_ddl
compiled,
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\sqlalchemy\engine\base.py", line 1288, in _execute_context
e, statement, parameters, cursor, context
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\sqlalchemy\engine\base.py", line 1482, in _handle_dbapi_exception
sqlalchemy_exception, with_traceback=exc_info[2], from_=e
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\sqlalchemy\util\compat.py", line 178, in raise_
raise exception
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\sqlalchemy\engine\base.py", line 1248, in _execute_context
cursor, statement, parameters, context
File "d:\l_pipe\vessel_app_celery\vessel_env\lib\site-packages\sqlalchemy\engine\default.py", line 588, in do_execut cursor.execute(statement, parameters)
sqlalchemy.exc.ProgrammingError: (psycopg2.errors.InvalidForeignKey) there is no unique constraint matching given keys for referenced table "dicom"
[SQL:
CREATE TABLE "DicomFormData" (
id SERIAL NOT NULL,
session_id VARCHAR(200) NOT NULL,
date_uploaded TIMESTAMP WITHOUT TIME ZONE NOT NULL,
study_name VARCHAR(300) NOT NULL,
description VARCHAR(1000) NOT NULL,
PRIMARY KEY (id),
)
]
解决方案 需要使用 db.Unique Constraint 添加表参数
class Dicom(db.Model):
__tablename__ = 'dicom'
## data unqine id
__table_args__ = (
# this can be db.PrimaryKeyConstraint if you want it to be a primary key
db.UniqueConstraint('session_id'),
)
id = db.Column(db.Integer, primary_key=True)
date_uploaded = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
userReact_id = db.Column(db.Integer, db.ForeignKey('UserReact.id'), nullable=True)
dicom_stack = db.Column(db.LargeBinary, nullable=False)
thumbnail = db.Column(db.LargeBinary, nullable=False)
file_count = db.Column(db.Integer, nullable=True)
session_id = db.Column(db.String(200), nullable=False)
#uselist one to one relationship
formData = db.relationship('DicomFormData', uselist=True, backref='author', lazy=True)
def __repr__(self):
return f"Dicom('{self.date_uploaded}')"
class DicomFormData(db.Model):
id = db.Column(db.Integer, primary_key=True)
date_uploaded = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
study_name = db.Column(db.String(300), nullable=False)
description = db.Column(db.String(1000), nullable=False)
session_id = db.Column(db.String(200), db.ForeignKey('dicom.session_id'), nullable=False)
def __repr__(self):
return f"DicomFormData('{self.study_name}')"
class Dicom(db.Model):
__tablename__ = 'dicom'
id = db.Column(db.Integer, primary_key=True, unique=True)
这是我今天刚学到的东西。
我还有一个列声明为primary_key，但flask-migrate没有将其检测为唯一约束。
我想传递参数 unique 就是解决这个问题的方法。因为我看到，当我传递唯一参数时，flask-migrate 会检测到此更改，即向名为“id”的表添加新的唯一约束。