使用 Flask alchemy 创建数据库

问题描述 投票：0回答：1

我尝试通过创建 Movie 类的新对象向 sql alchemy 数据库添加新数据。 我使用 Movie api 来获取数据信息。 尝试打印 api 的响应，效果很好。 但我在 db.sessoin.commit() 时遇到错误

这是代码：



from flask import Flask, render_template, redirect, url_for, request
from flask_bootstrap import Bootstrap5
from flask_sqlalchemy import SQLAlchemy
from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField, EmailField, SubmitField, DecimalField
from wtforms.validators import DataRequired
import requests



class Movie(db.Model):
    id = db.Column(db.Integer, primary_key=True, autoincrement=True)

    title = db.Column(db.String(400), nullable=False)
    year = db.Column(db.String(400), nullable=False)
    description = db.Column(db.String(1000), nullable=False)
    img_url = db.Column(db.String(800), nullable=False)

    rating = db.Column(db.String(400), nullable=True)
    ranking = db.Column(db.Integer, nullable=True)
    review = db.Column(db.String(400), nullable=True)




@app.route("/select")
def find():
    movie_id = request.args.get('id')
    movie_url = f"https://api.themoviedb.org/3/movie/{movie_id}"
    params = {
        "api_key" : api_key, 
        "language": "en-US"
    }
    response = requests.get(url=movie_url, params = params)
    response = response.json()
    new_data = Movie(
        title = response['title'],
        description = response['overview'],
        year = response['release_date'],
        img_url = f"https://image.tmdb.org/t/p/w500{response['poster_path']}"
    )
    db.session.add(new_data)
    db.session.commit()
    
    return render_template("base.html")

这是我遇到的错误

WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead.
 * Running on http://127.0.0.1:5000
Press CTRL+C to quit
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 121-365-366
127.0.0.1 - - [14/Aug/2023 16:25:02] "GET /select?id=1142216 HTTP/1.1" 500 -
Traceback (most recent call last):
  File "S:\Python\lib\site-packages\sqlalchemy\engine\base.py", line 1963, in _exec_single_context
    self.dialect.do_execute(
  File "S:\Python\lib\site-packages\sqlalchemy\engine\default.py", line 920, in do_execute        
    cursor.execute(statement, parameters)
sqlite3.IntegrityError: NOT NULL constraint failed: movie.rating

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "S:\Python\lib\site-packages\flask\app.py", line 2213, in __call__
    return self.wsgi_app(environ, start_response)
  File "S:\Python\lib\site-packages\flask\app.py", line 2193, in wsgi_app
    response = self.handle_exception(e)
  File "S:\Python\lib\site-packages\flask\app.py", line 2190, in wsgi_app
    response = self.full_dispatch_request()
  File "S:\Python\lib\site-packages\flask\app.py", line 1486, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "S:\Python\lib\site-packages\flask\app.py", line 1484, in full_dispatch_request
    rv = self.dispatch_request()
  File "S:\Python\lib\site-packages\flask\app.py", line 1469, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)
  File "d:\Data Transfer\Coding\Python\3 Udemy Course\Udemy Codes\udemy_learning_codes\64_1\main.py", line 142, in find
    db.session.commit()
  File "S:\Python\lib\site-packages\sqlalchemy\orm\scoping.py", line 553, in commit
    return self._proxied.commit()
  File "S:\Python\lib\site-packages\sqlalchemy\orm\session.py", line 1905, in commit
    trans.commit(_to_root=True)
  File "<string>", line 2, in commit
  File "S:\Python\lib\site-packages\sqlalchemy\orm\state_changes.py", line 137, in _go
    ret_value = fn(self, *arg, **kw)
  File "S:\Python\lib\site-packages\sqlalchemy\orm\session.py", line 1220, in commit
    self._prepare_impl()
  File "<string>", line 2, in _prepare_impl
  File "S:\Python\lib\site-packages\sqlalchemy\orm\state_changes.py", line 137, in _go
    ret_value = fn(self, *arg, **kw)
  File "S:\Python\lib\site-packages\sqlalchemy\orm\session.py", line 1195, in _prepare_impl
    self.session.flush()
  File "S:\Python\lib\site-packages\sqlalchemy\orm\session.py", line 4153, in flush
    self._flush(objects)
  File "S:\Python\lib\site-packages\sqlalchemy\orm\session.py", line 4289, in _flush
    with util.safe_reraise():
  File "S:\Python\lib\site-packages\sqlalchemy\util\langhelpers.py", line 147, in __exit__
    raise exc_value.with_traceback(exc_tb)
  File "S:\Python\lib\site-packages\sqlalchemy\orm\session.py", line 4250, in _flush
    flush_context.execute()
  File "S:\Python\lib\site-packages\sqlalchemy\orm\unitofwork.py", line 467, in execute
    rec.execute(self)
  File "S:\Python\lib\site-packages\sqlalchemy\orm\unitofwork.py", line 644, in execute
    util.preloaded.orm_persistence.save_obj(
  File "S:\Python\lib\site-packages\sqlalchemy\orm\persistence.py", line 93, in save_obj
    _emit_insert_statements(
  File "S:\Python\lib\site-packages\sqlalchemy\orm\persistence.py", line 1223, in _emit_insert_statements
    result = connection.execute(
  File "S:\Python\lib\site-packages\sqlalchemy\engine\base.py", line 1413, in execute
    return meth(
  File "S:\Python\lib\site-packages\sqlalchemy\sql\elements.py", line 483, in _execute_on_connection
    return connection._execute_clauseelement(
  File "S:\Python\lib\site-packages\sqlalchemy\engine\base.py", line 1637, in _execute_clauseelement
    ret = self._execute_context(
  File "S:\Python\lib\site-packages\sqlalchemy\engine\base.py", line 1841, in _execute_context
    return self._exec_single_context(
  File "S:\Python\lib\site-packages\sqlalchemy\engine\base.py", line 1982, in _exec_single_context
    self._handle_dbapi_exception(
  File "S:\Python\lib\site-packages\sqlalchemy\engine\base.py", line 2339, in _handle_dbapi_exception
    raise sqlalchemy_exception.with_traceback(exc_info[2]) from e
  File "S:\Python\lib\site-packages\sqlalchemy\engine\base.py", line 1963, in _exec_single_context
    self.dialect.do_execute(
  File "S:\Python\lib\site-packages\sqlalchemy\engine\default.py", line 920, in do_execute
    cursor.execute(statement, parameters)
sqlalchemy.exc.IntegrityError: (sqlite3.IntegrityError) NOT NULL constraint failed: movie.rating
[SQL: INSERT INTO movie (title, year, description, img_url, rating, ranking, review) VALUES (?, ?, ?, ?, ?, ?, ?)]
[parameters: ('The Lady of Silence: The Mataviejitas Murders', '2023-07-27', 'Between 1998 and 2005, a wave of murders targeting elderly women hit Mexico City, triggering the hunt for — and capture — of a most unlikely suspect.', 'https://image.tmdb.org/t/p/w500/qmW8mPhcdOP3v36Gz8WEeDdewFN.jpg', None, None, None)]
(Background on this error at: https://sqlalche.me/e/20/gkpj)
127.0.0.1 - - [14/Aug/2023 16:25:02] "GET /select?__debugger__=yes&cmd=resource&f=style.css HTTP/1.1" 304 -
127.0.0.1 - - [14/Aug/2023 16:25:02] "GET /select?__debugger__=yes&cmd=resource&f=debugger.js HTTP/1.1" 304 -
127.0.0.1 - - [14/Aug/2023 16:25:02] "GET /select?__debugger__=yes&cmd=resource&f=console.png HTTP/1.1" 304 -
127.0.0.1 - - [14/Aug/2023 16:25:02] "GET /select?__debugger__=yes&cmd=resource&f=console.png HTTP/1.1" 304 -

我想向sql alchemy数据库添加数据。

flask sqlalchemy flask-sqlalchemy
1个回答
0
投票

似乎可空约束在出于某种原因创建时并未添加到表中。如果您使用的是 sqlite，您可以使用数据库浏览器https://sqlitebrowser.org/轻松检查架构。如果需要，您还可以使用它来更新架构并添加/删除 NOT NULL 约束。如果您使用 PostgreSQL，您也可以在 pgAdmin4 中执行相同的操作。

您还可以尝试使用flask-migrate迁移数据库https://pypi.org/project/Flask-Migrate/并按照简单的示例进行操作，看看它是否正确更新了架构

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