I am using Flask, SQLAlchemy, Marshmallow etc....
This Flask method saves the objects to the database fine, however it errors on the return statement.
This is the parent class:
class Weather(db.Model):
"""Weather definition for SQLAlchemy"""
id = db.Column(db.Integer, primary_key=True, autoincrement=True)
coordinates = db.relationship("Coordinate", backref="Weather", uselist=False) # coordinates (decmial)
hygrometer = db.Column(db.Float, nullable=False) # hygrometer (0.0 -100)
thermometer = db.Column(db.Float, nullable=False) # thermometer (-200 - 200)
udometer = db.Column(db.Integer, nullable=False) # udometer (0-3000)
anemometer = db.Column(db.Integer, nullable=False) # anemometer (0-500)
vane = db.Column(db.Integer, nullable=False) # vane (0-360)
#date = db.Column(db.String, nullable=False) # this is the old manual
date = db.Column(db.DateTime(timezone=True), default=func.now()) # this gets auto generated
def __repr__(self):
return '<Weather %r>' % self.id
class WeatherSchema(ma.SQLAlchemyAutoSchema):
class Meta:
fields = ("id", "coordinates", "hygrometer", "thermometer", "udometer", "anemometer", "vane", "date")
weather_schema = WeatherSchema()
weathers_schema = WeatherSchema(many=True)
This is the child class:
class Coordinate(db.Model):
id = db.Column(db.Integer, primary_key=True, autoincrement=True)
longitude = db.Column(db.Float, nullable=False) # coordinates (decmial)
latitude = db.Column(db.Float, nullable=False) # coordinates (decmial)
Weather_id = db.Column(db.Integer, db.ForeignKey("weather.id"), nullable=False)
def __repr__(self):
return '<Coordinate %r>' % self.id
class CoordinateSchema(ma.SQLAlchemyAutoSchema):
# definition used by serialization library based on user
class Meta:
fields = ("id", "longitude", "latitude", "weather_id")
coordinate_schema = CoordinateSchema()
coordinates_schema = CoordinateSchema(many=True)
This is the method:
@app.post("/weathers/add") # ADD
def weather_add_json():
request_data = request.get_json()
print(request_data)
new_coordinate = Coordinate(
longitude=request_data['longitude'],
latitude=request_data['latitude']
)
new_weather = Weather(
coordinates=new_coordinate,
hygrometer=request_data['hygrometer'],
thermometer=request_data['thermometer'],
udometer=request_data['udometer'],
anemometer=request_data['anemometer'],
vane=request_data['vane']
)
print(new_weather)
try:
db.session.add(new_weather)
db.session.commit()
print("Record added to DB")
print(json.dumps(request_data, indent=4))
except Exception as e:
print(e)
return weather_schema.jsonify(new_weather)
This is the HTTP request:
POST http://127.0.0.1:5000/weathers/add
Content-Type: application/json
{
"longitude": "45.5",
"latitude": "92.6",
"hygrometer": "1.5",
"thermometer": "22.5",
"udometer": "2200",
"anemometer": "250",
"vane": "92"
}
This is the error:
line 179, in default
raise TypeError(f'Object of type {o.__class__.__name__} '
TypeError: Object of type Coordinate is not JSON serializable
127.0.0.1 - - [27/Dec/2021 18:51:24] "POST /weathers/add HTTP/1.1" 500 -
The below is the content of each table:
Weather:
4,1.5,22.5,2200,250,92,2021-12-27 18:22:16
5,1.5,22.5,2200,250,92,2021-12-27 18:35:31
6,1.5,22.5,2200,250,92,2021-12-27 18:36:43
7,1.5,22.5,2200,250,92,2021-12-27 18:38:28
Coordinate:
4,45.5,92.6,4
5,45.5,92.6,5
6,45.5,92.6,6
7,45.5,92.6,7
This structure for parent-child was done following a guide, however i feel as though it is wrong, it fails 3NF and doesn't actually reference coordinates from the weather table.
Should it be a Weather -> WeatherCoordinate -> Coordinate ? I'm not sure how I would structure this though, maybe an entirely new object or can this be scaffolded automatically?
