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将表单数据表单提交到mysql数据库时，我完全陷入了以下错误，非常感谢任何线索

我收到此错误：

“sqlalchemy.orm.exc.FlushError FlushError: Instance has a NULL identity key. 如果这是一个自动生成的值，请检查数据库表是否允许生成新的主键值，并且映射的 Column 对象是否配置为期望这些“

代码是：

from flask import Flask, request,redirect,render_template,flash
from wtforms import Form, TextField, BooleanField
from wtforms.validators import Required
from flask.ext.sqlalchemy import SQLAlchemy

app = Flask(__name__)
db = SQLAlchemy(app)

app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql://root:@127.0.0.1/Jungle'

class Sighting(db.Model):
    __tablename__ = 'Animals'
    animal_name = db.Column(db.String, primary_key = True)
    animal_type = db.Column(db.String)
    scary = db.Column(db.String)

class LoginForm(Form):
    animal_name = TextField('Animal')
    animal_type = TextField('Type')
    scary = BooleanField('Scary')

@app.route('/login',methods = ['GET','POST'])
def login():
    form = LoginForm()    
    if request.method == 'POST':
        newanimal = Sighting(animal_name=form.animal_name.data,animal_type=form.animal_type.data,scary=form.scary.data)
        db.session.add(newanimal)
        db.session.commit()
        return redirect('/thanks')
    elif request.method == 'GET':
        return render_template('login.html', form = form)

@app.route('/thanks',methods= ['GET'])
def thanks():
    return render_template('thanks.html')

if __name__ == '__main__':
  app.run(debug=True)

如果我在上面的代码中运行这样的东西，它可以工作并成功提交到数据库中：

@app.route('/submit',methods =['GET'])
def submit():
    newanimal = Sighting(animal_name='frog',animal_type='amphibian', scary='No')
    db.session.add(newanimal)
    db.session.commit()
    return render_template('thanks.html')

所以它似乎与表单数据有关。MySQL表是：

CREATE TABLE `Animals` (
  `animal_name` varchar(100) DEFAULT NULL,
  `animal_type` varchar(100) DEFAULT NULL,
  `scary` varchar(100) DEFAULT NULL,
  `id` int(11) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`id`),
  UNIQUE KEY `id` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=21 DEFAULT CHARSET=utf8

即使发生其中一个失败的提交，数据库表似乎也会自动增加 - 当您手动输入一行时，它的 id 比前一个高一些。表中还有一行，每个字段都为空。

提前谢谢了！！

（原谅奇怪的命名模式 - 它改编自教程）

sqlalchemy.orm.exc.FlushError
FlushError: Instance <Sighting at 0x10c6552d0> has a NULL identity key.  If this is an auto-generated value, check that the database table allows generation of new primary key values, and that the mapped Column object is configured to expect these generated values.  Ensure also that this flush() is not occurring at an inappropriate time, such aswithin a load() event.

Traceback (most recent call last)
File "/Library/Python/2.7/site-packages/flask/app.py", line 1836, in __call__
return self.wsgi_app(environ, start_response)
File "/Library/Python/2.7/site-packages/flask/app.py", line 1820, in wsgi_app
response = self.make_response(self.handle_exception(e))
File "/Library/Python/2.7/site-packages/flask/app.py", line 1403, in handle_exception
reraise(exc_type, exc_value, tb)
File "/Library/Python/2.7/site-packages/flask/app.py", line 1817, in wsgi_app
response = self.full_dispatch_request()
File "/Library/Python/2.7/site-packages/flask/app.py", line 1477, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/Library/Python/2.7/site-packages/flask/app.py", line 1381, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/Library/Python/2.7/site-packages/flask/app.py", line 1475, in full_dispatch_request
rv = self.dispatch_request()
File "/Library/Python/2.7/site-packages/flask/app.py", line 1461, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/Users/tomhalloran/TomDev/FlaskSkint/learnv3.py", line 29, in login
db.session.commit()
File "/Library/Python/2.7/site-packages/sqlalchemy/orm/scoping.py", line 149, in do
return getattr(self.registry(), name)(*args, **kwargs)
File "/Library/Python/2.7/site-packages/sqlalchemy/orm/session.py", line 765, in commit
self.transaction.commit()
File "/Library/Python/2.7/site-packages/sqlalchemy/orm/session.py", line 370, in commit
self._prepare_impl()
File "/Library/Python/2.7/site-packages/sqlalchemy/orm/session.py", line 350, in _prepare_impl
self.session.flush()
File "/Library/Python/2.7/site-packages/sqlalchemy/orm/session.py", line 1879, in flush
self._flush(objects)
File "/Library/Python/2.7/site-packages/sqlalchemy/orm/session.py", line 1997, in _flush
transaction.rollback(_capture_exception=True)
File "/Library/Python/2.7/site-packages/sqlalchemy/util/langhelpers.py", line 57, in __exit__
compat.reraise(exc_type, exc_value, exc_tb)
File "/Library/Python/2.7/site-packages/sqlalchemy/orm/session.py", line 1967, in _flush
flush_context.finalize_flush_changes()
File "/Library/Python/2.7/site-packages/sqlalchemy/orm/unitofwork.py", line 387, in finalize_flush_changes
self.session._register_newly_persistent(other)
File "/Library/Python/2.7/site-packages/sqlalchemy/orm/session.py", line 1389, in _register_newly_persistent
% state_str(state)
FlushError: Instance <Sighting at 0x10c6552d0> has a NULL identity key. If this is an auto-generated value, check that the database table allows generation of new primary key values, and that the mapped Column object is configured to expect these generated values. Ensure also that this flush() is not occurring at an inappropriate time, such aswithin a load() event.
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1 回答 1

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您创建了表单，但除非我误读了您的代码，否则您错过了使用来自 POST（即来自 request.form）的数据实际填充表单的步骤。

于 2014-01-23T04:52:14.517 回答