3
每当我使用session和SqlAlchemy执行更新语句，然后调用commit()时，它几乎不会更新数据库。Postgres和SqlAlchemy没有正确更新行
这是我的环境： 我有两台服务器在运行。一个是我的数据库，另一个是我的python服务器。
数据库服务器：
Postgres v9.6- 在与Python亚马逊RDS
服务器
Linux 3.13.0-65-generic x86_64- 在Amazon EC2实例SqlAlchemy v1.1.5Python v3.4.3Flask 0.11.1
还有，我用pgAdmin 4查询我的表。
重要的文件：
server/models/category.py
from sqlalchemy.orm import backref
from .. import db
from flask import jsonify
class Category(db.Model):
__tablename__ = "categories"
id = db.Column(db.Integer, primary_key=True)
cat_name = db.Column(db.String(80))
includes = db.Column(db.ARRAY(db.String), default=[])
excludes = db.Column(db.ARRAY(db.String), default=[])
parent_id = db.Column(db.ForeignKey('categories.id', ondelete='SET NULL'), nullable=True, default=None)
subcategories = db.relationship('Category', backref=backref(
'categories',
remote_side=[id],
single_parent=True,
cascade="all, delete-orphan"
))
assigned_user = db.Column(db.String(80), nullable=True, default=None)
def to_dict(self):
return dict(
id=self.id,
cat_name=self.cat_name,
parent_id=self.parent_id,
includes=self.includes,
excludes=self.excludes,
assigned_user=self.assigned_user,
)
def json(self):
return jsonify(self.to_dict())
def __repr__(self):
return "<%s %r>" % (self.__class__, self.to_dict())
class CategoryOperations:
...
@staticmethod
def update_category(category):
return """
UPDATE categories
SET cat_name='{0}',
parent_id={1},
includes='{2}',
excludes='{3}',
assigned_user={4}
WHERE id={5}
RETURNING cat_name, parent_id, includes, excludes, assigned_user
""".format(
category.cat_name,
category.parent_id if category.parent_id is not None else 'null',
"{" + ",".join(category.includes) + "}",
"{" + ",".join(category.excludes) + "}",
"'" + category.assigned_user + "'" if category.assigned_user is not None else 'null',
category.id
)
@staticmethod
def update(category, session):
print("Updating category with id: " + str(category.id))
stmt = CategoryOperations.update_category(category)
print(stmt)
row_updated = session.execute(stmt).fetchone()
return Category(
id=category.id,
cat_name=row_updated[0],
parent_id=row_updated[1],
includes=row_updated[2],
excludes=row_updated[3],
assigned_user=row_updated[4]
)
...
server/api/category.py
from flask import jsonify, request
import json
from .api_utils.utils import valid_request as is_valid_request
from . import api
from ..models.category import Category, CategoryOperations
from ..models.users_categories import UsersCategoriesOperations, UsersCategories
from ..models.listener_item import ListenerItemOperations, ListenerItem
from ..models.user import UserOperations
from ..schemas.category import category_schema
from .. import get_session
...
@api.route('/categories/<int:id>', methods=['PUT'])
def update_category(id):
category_json = request.json
if category_json is None:
return "Bad Request: Request not sent as json", 400
valid_json, json_err = is_valid_request(category_json, ['cat_name', 'parent_id', 'includes', 'excludes', 'assigned_user'], "and")
if not valid_json:
return json_err, 400
category = Category(
id=id,
cat_name=category_json['cat_name'],
parent_id=category_json['parent_id'],
includes=category_json['includes'],
excludes=category_json['excludes'],
assigned_user=category_json['assigned_user'],
)
session = get_session()
try:
updated_category = CategoryOperations.update(category, session)
session.commit()
print(updated_category.to_dict())
return jsonify(updated_category.to_dict()), 200
except Exception as e:
print("ROLLBACK")
print(e)
session.rollback()
return str(e), 500
...
还有一个文件，该文件可能会是有用的，这种情况下：
server/__init__.py
import sqlalchemy as sa
from flask import Flask
from flask_marshmallow import Marshmallow
from flask_sqlalchemy import SQLAlchemy
from config import config
from sqlalchemy.orm import scoped_session, sessionmaker
from sqlalchemy.ext.declarative import declarative_base
from flask_cors import CORS, cross_origin
from .db_config import CONFIG
db = SQLAlchemy()
ma = Marshmallow()
Engine = sa.create_engine(
CONFIG.POSTGRES_URL,
client_encoding='utf8',
pool_size=20,
max_overflow=0
)
Session = sessionmaker(bind=Engine)
conn = Engine.connect()
def get_session():
return Session(bind=conn)
def create_app(config_name):
app = Flask(__name__, static_url_path="/app", static_folder="static")
app_config = config[config_name]()
print(app_config)
app.config.from_object(app_config)
from .api import api as api_blueprint
app.register_blueprint(api_blueprint, url_prefix='/api')
from .api.routes import routes
routes(app)
from .auth import authentication
authentication(app)
db.init_app(app)
ma.init_app(app)
CORS(app)
...
return app
为了解释多一点与我所提供的环境和文件，让我们说我有我的类别表中的一行，像这样：
{
"assigned_user": null,
"cat_name": "Category Name Before",
"excludes": [
"exclude1",
"excludeBefore"
],
"id": 2,
"includes": [
"include1",
"include2"
],
"parent_id": null
}
当我做一个PUT请求/api/categories/2与身体为：
{
"assigned_user": null,
"cat_name": "Category Name 1",
"excludes": [
"exclude1",
"exclude2"
],
"id": 2,
"includes": [
"include1",
"include2"
],
"parent_id": null
}
在要求，我打印出来，我的PUT请求创建（测试）的SQL语句，我得到这个：
UPDATE categories
SET cat_name='Category Name 1',
parent_id=null,
includes='{include1,include2}',
excludes='{exclude1,exclude2}',
assigned_user=null
WHERE id=2
RETURNING cat_name, parent_id, includes, excludes, assigned_user
其提交UPDATE语句后，然后返回响应。我得到更新的对象回，像这样：
{
"assigned_user": null,
"cat_name": "Category Name 1",
"excludes": [
"exclude1",
"exclude2"
],
"id": 2,
"includes": [
"include1",
"include2"
],
"parent_id": null
}
当我做这个URL GET请求：/api/categories/2，我也得到相同的对象太像这样：
{
"assigned_user": null,
"cat_name": "Category Name 1",
"excludes": [
"exclude1",
"exclude2"
],
"id": 2,
"includes": [
"include1",
"include2"
],
"parent_id": null
}
然而，当我运行下面pgAdmin，我得到的是旧版本的SQL命令（它没有更新数据库行）：
SELECT * FROM categories WHERE id=2
这里是我的对象得到：
{
"assigned_user": null,
"cat_name": "Category Name Before",
"excludes": [
"exclude1",
"excludeBefore"
],
"id": 2,
"includes": [
"include1",
"include2"
],
"parent_id": null
}
这是我在做PUT请求之前的对象。如果我重新启动我的python服务器并执行GET请求，那么我会得到旧的对象。感觉就像在会话中一样，它存储数据，但由于某种原因它不会传播到数据库。
知道如果我在pgAdmin中运行更新命令，它可能会很好地更新行。
更新：我也用这些方法（如谈到here）进行更新，但还是同样的问题：
# using the session to update
session.query(Category).filter_by(id=category.id).update({
"cat_name": category.id,
"assigned_user": category.assigned_user,
"includes": category.includes,
"excludes": category.excludes,
"parent_id": category.parent_id
})
# using the category object to edit, then commit
category_from_db = session.query(Category).filter_by(id=category.id).first()
category_from_db.cat_name = category_json['cat_name']
category_from_db.assigned_user = category_json['assigned_user']
category_from_db.excludes = category_json['excludes']
category_from_db.includes = category_json['includes']
category_from_db.parent_id = category_json['parent_id']
session.commit()
任何想法？