使用 sqlalchemy 将 json 文件的某些键的值写入 postgresql 表

Question

How do I write the values of certain keys contained in the result.json file to the table I created. the values in the certain keys will be written in the columns I have created. I have id, title, score columns in my table. I want to write the value opposite the title key in the title column and the value opposite the score key in the score column.

result.son file:

[
  {
    "title": "Street Basketball Association",
    "appId": "com.sba.android.googleplay",
    "url": "https://play.google.com/store/apps/details?id=com.sba.android.googleplay",
    "icon": "https://play-lh.googleusercontent.com/a17t8kK_A4TMJtV0l6oTGzOvLbu_QlnKiWZM3L4RB-xprNL57z1YAJlal9ewEPrWxrW3=w240-h480-rw",
    "developer": "ShakaChen",
    "currency": "USD",
    "price": 0,
    "free": true,
    "summary": "We will bring you the hottest basketball game experience.You can invite other players to a real-time online competition or rank up while playing various league, cups and events in spectacular arenas.",
    "scoreText": "4.0",
    "score": 4.315321
  }
]

the name of my database is test :in this database, I have a table with one test_table .

My code:

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy.dialects.postgresql import JSON


app.config['SQLALCHEMY_DATABASE_URI'] = 'postgres://username:password@localhost:5432/test'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = True

db = SQLAlchemy(app)


class Test(test.Model):
    __tablename__ = 'test_table'
    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String(255))
    score = db.Column(db.Float)

with open('./result.json') as my_file:
    dicts = load(my_file)

for dictionary in dicts:
    test_data = Test(app_name=dictionary['title'],
                                    developer=dictionary['developer'],
                                    score=dictionary['score'])

    db.session.add(test_data)
    db.session.commit()

Answer 1

First of all, your Person model has score field set to db.Integer , yet in the data you're getting, score is set to float . This will cause a Data MisMatch error.

Now, for the json part.

You import the load method from the json module so you're able to convert json objects to Python dicts .

from json import load

You open your file, preferably inside a context so the file gets automatically released once you're done with it.

with open('result.json') as my_file:
    dicts = load(my_file)

Now dicts is a list of dict objects on which you can operate. You initiate a new instance of your Person db.model and assign each of the values to the appropriate field.

for dictionary in dicts: #Remember, you have a list of dicts.
    person = Person(app_id=dictionary['appId'], 
                  title=dictionary['title'], score=dictionary['score']) 
                  #Remember to set the score field to the appropriate datatype. 
                  #i.e: db.Float
    db.session.add(person) #Add your new person instance to the session.
    db.session.commit() #Persists the user to your database.

Update : Based from what I understood from your comment. You can set your db.Model as follows:

class Person(db.Model):
    __tablename__ = 'test'
    id = db.Column(db.Integer, autoincrement=True, primary_key=True)
    app_id = db.Column(db.String(10), index=True)
    title = db.Column(db.String(255))
    score = db.Column(db.Float) #You're getting float values.

Now, you have the id set by your database and the app_id from the json file. And you always have the option to search by the former or the latter.