CODEWITHSUNDEEP
pythonpython-3.xsqlalchemyflask-sqlalchemy
SafeDev
SafeDev

Reputation: 672

Missing required position for __init__ method despite not implementing one

I'm currently trying to create Models for my database in SQLAlchemy, but whenever I try to create my database I keep running into this error despite not even implementing an __init__ function.

TypeError: __init__() missing 1 required positional argument: 'item_type'

I'm sure I'm missing something stupid, but can someone point me in the right direction

Base Model:

class EntityBase(db.Model):
    __abstract__ = True

    id = db.Column(db.Integer, primary_key=True)
    date_created = db.Column(db.TIMESTAMP, nullable=False, default=lambda: datetime.now())

Inherited Model:

class Recipe(db.Model):
    __tablename__ = 'Recipes'

    ingredients = db.Column(db.ARRAY, nullable=False)
    steps = db.Column(db.ARRAY, nullable=False)
    likes = db.Column(db.Integer, nullable=False, default=0)
    views = db.Column(db.Integer, nullable=False, default=0)
    title = db.Column(db.String, nullable=False)
    description = db.Column(db.String)

StackTrace:

File "infrastructure\data\database_models\recipe.py", line 5, in <module>
    class Recipe(db.Model):
File "infrastructure\data\database_models\recipe.py", line 8, in Recipe
    ingredients = db.Column(db.ARRAY, nullable=False)
File "backend\venv\lib\site-packages\sqlalchemy\sql\schema.py", line 1565, in __init__
    super(Column, self).__init__(name, type_)
File "backend\venv\lib\site-packages\sqlalchemy\sql\elements.py", line 4640, in __init__
    self.type = type_api.to_instance(type_)
File "backend\venv\lib\site-packages\sqlalchemy\sql\type_api.py", line 1631, in to_instance
    return typeobj(*arg, **kw)
TypeError: __init__() missing 1 required positional argument: 'item_type'

Upvotes: 0

Views: 639

Answers (2)

Barmar
Barmar

Reputation: 780723

The db.ARRAY() type requires the type of the array elements. So if ingredients is an array of integers, it would be:

ingredients = db.Column(db.ARRAY(db.Integer()), nullable=False)

Upvotes: 3

Cyberclops
Cyberclops

Reputation: 361

It appears that the constructor from db.model has a required parameter. Because your Recipe class is derived from db.model it must have a constructor that calls the super class and supplies this value. This will also be true of anything derived from your EntityBase class. The following is an example of how to properly do this.

class Recipe(db.Model):
    __tablename__ = 'Recipes'
    

    def __init__(self, item_type):
      super().__init__(item_type)
      ...

Upvotes: 0

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