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[英]Aggreate join query using Flask-SQLAlchemy and Flask-Marshmallow
[英]Empty Json using Flask-Marshmallow and SQLAlchemy
我正在嘗試創建一個端點以從兩個表指示符和元數據返回數據,因此我創建了下面的 model, indicator = db.relationship('Indicator', backref='metadatas')
和indicator_id = db.Column(db.Integer, db.ForeignKey('indicator.id'))
但是當我調用api/indicators
時,我得到了空的 json,你可以在最后看到,為什么?
模型.py
from datetime import datetime
from app import db, ma
class Indicator(db.Model):
id = db.Column(db.Integer, primary_key=True)
unique_key = db.Column(db.String(32))
name = db.Column(db.String(255))
short_name = db.Column(db.String(255))
valid = db.Column(db.Boolean)
created_at = db.Column(db.DateTime())
last_updated_at = db.Column(db.DateTime())
class Metadata(db.Model):
id = db.Column(db.Integer, primary_key=True)
indicator_id = db.Column(db.Integer, db.ForeignKey('indicator.id'))
indicator = db.relationship('Indicator', backref='metadatas')
type = db.Column(db.String(255))
inputs = db.Column(db.String(255))
options = db.Column(db.String(255))
outputs = db.Column(db.String(255))
class IndicatorSchema(ma.SQLAlchemySchema):
class Meta:
model = Indicator
id: ma.auto_field()
unique_key: ma.auto_field()
name: ma.auto_field()
short_name: ma.auto_field()
valid: ma.auto_field()
class MetadataSchema(ma.SQLAlchemyAutoSchema):
class Meta:
model = Metadata
include_fk = True
您可以在下面看到其他文件:
應用程序.py
from flask_jwt_extended import JWTManager
from flask import Flask, jsonify, request
from flask_sqlalchemy import SQLAlchemy
from flask_marshmallow import Marshmallow
app = Flask(__name__)
app.config["JWT_SECRET_KEY"] = "fe7e8955db51c0ff78550419434128cb"
app.config["JWT_ACCESS_TOKEN_EXPIRES "] = 28800
app.config['SQLALCHEMY_DATABASE_URI'] = "sqlite:////tmp/test.db"
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = True
app.config['JSON_SORT_KEYS'] = False
db = SQLAlchemy(app)
ma = Marshmallow(app)
controller.py
from flask_jwt_extended import jwt_required, create_access_token, get_jwt_identity
from flask import Flask, request, jsonify
from models import Indicator, Metadata, IndicatorSchema, MetadataSchema
from config import conn_string
from app import app, db
import services
import hashlib
import json
@app.route('/api/indicators', methods=['GET'])
@jwt_required()
def indicators():
short_name = request.args.get('short_name',None)
if short_name is not None:
indicator = Indicator.query.filter_by(short_name = short_name).first()
indicator_schema = IndicatorSchema()
output = indicator_schema.dump(indicator)
else:
indicators = Indicator.query.all()
indicators_schema = IndicatorSchema(many=True)
output = indicators_schema.dump(indicators)
return jsonify(output), 200
當我調用/api/indicators
時,我得到響應200
但為空 JSON:
$ http :5000/api/indicators
HTTP/1.0
Content-Type: application/json
Server: Werkzeug/2.0.0 Python/3.8.5
[
{},
{},
{},
{},
{},
{}
]
我認為有兩個問題:
Indicator
model 上定義關系(一個具有許多元數據的指標)include_relationships
,因為您希望返回的不僅僅是外鍵 ID您的代碼進行了調整:
from datetime import datetime
from app import db, ma
class Indicator(db.Model):
__tablename__ = "indicator"
id = db.Column(db.Integer, primary_key=True)
unique_key = db.Column(db.String(32))
name = db.Column(db.String(255))
short_name = db.Column(db.String(255))
valid = db.Column(db.Boolean)
created_at = db.Column(db.DateTime())
last_updated_at = db.Column(db.DateTime())
metadatas = db.relationship('Metadata', backref='indicator')
class Metadata(db.Model):
__tablename__ = "metadata"
id = db.Column(db.Integer, primary_key=True)
indicator_id = db.Column(db.Integer, db.ForeignKey('indicator.id'))
type = db.Column(db.String(255))
inputs = db.Column(db.String(255))
options = db.Column(db.String(255))
outputs = db.Column(db.String(255))
class IndicatorSchema(ma.SQLAlchemyAutoSchema):
class Meta:
model = Indicator
include_relationships = True
id: ma.auto_field()
unique_key: ma.auto_field()
name: ma.auto_field()
short_name: ma.auto_field()
valid: ma.auto_field()
class MetadataSchema(ma.SQLAlchemyAutoSchema):
class Meta:
model = Metadata
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