liniting and applying black

.flake8

@@ -1,4 +1,5 @@
 [flake8]
-ignore = ANN101
+ignore = ANN101, ANN102, W503
 max-complexity = 10
+max-line-length = 88
 exclude = p38venv,.pytest_cache

orm/__init__.py

@@ -1,6 +1,18 @@
 from orm.exceptions import ModelDefinitionError, ModelNotSet, MultipleMatches, NoMatch
-from orm.fields import BigInteger, Boolean, Date, DateTime, Decimal, Float, ForeignKey, Integer, JSON, String, Text, \
-    Time
+from orm.fields import (
+    BigInteger,
+    Boolean,
+    Date,
+    DateTime,
+    Decimal,
+    Float,
+    ForeignKey,
+    Integer,
+    JSON,
+    String,
+    Text,
+    Time,
+)
 from orm.models import Model
 
 __version__ = "0.0.1"
@@ -21,5 +33,5 @@ __all__ = [
     "ModelDefinitionError",
     "ModelNotSet",
     "MultipleMatches",
-    "NoMatch"
+    "NoMatch",
 ]

orm/fields.py

@@ -1,14 +1,15 @@
 import datetime
 import decimal
-from typing import List, Optional, TYPE_CHECKING, Type, Any, Union
-
-import sqlalchemy
-from pydantic import Json, BaseModel
-from pydantic.fields import ModelField
+from typing import Any, List, Optional, TYPE_CHECKING, Type, Union
 
 import orm
 from orm.exceptions import ModelDefinitionError, RelationshipInstanceError
 
+from pydantic import BaseModel, Json
+from pydantic.fields import ModelField
+
+import sqlalchemy
+
 if TYPE_CHECKING:  # pragma no cover
     from orm.models import Model
 
@@ -16,33 +17,39 @@ if TYPE_CHECKING:  # pragma no cover
 class BaseField:
     __type__ = None
 
-    def __init__(self, *args, **kwargs) -> None:
-        name = kwargs.pop('name', None)
+    def __init__(self, *args: Any, **kwargs: Any) -> None:
+        name = kwargs.pop("name", None)
         args = list(args)
         if args:
             if isinstance(args[0], str):
                 if name is not None:
-                    raise ModelDefinitionError('Column name cannot be passed positionally and as a keyword.')
+                    raise ModelDefinitionError(
+                        "Column name cannot be passed positionally and as a keyword."
+                    )
                 name = args.pop(0)
 
         self.name = name
-        self.primary_key = kwargs.pop('primary_key', False)
-        self.autoincrement = kwargs.pop('autoincrement', self.primary_key and self.__type__ == int)
+        self.primary_key = kwargs.pop("primary_key", False)
+        self.autoincrement = kwargs.pop(
+            "autoincrement", self.primary_key and self.__type__ == int
+        )
 
-        self.nullable = kwargs.pop('nullable', not self.primary_key)
-        self.default = kwargs.pop('default', None)
-        self.server_default = kwargs.pop('server_default', None)
+        self.nullable = kwargs.pop("nullable", not self.primary_key)
+        self.default = kwargs.pop("default", None)
+        self.server_default = kwargs.pop("server_default", None)
 
-        self.index = kwargs.pop('index', None)
-        self.unique = kwargs.pop('unique', None)
+        self.index = kwargs.pop("index", None)
+        self.unique = kwargs.pop("unique", None)
 
-        self.pydantic_only = kwargs.pop('pydantic_only', False)
+        self.pydantic_only = kwargs.pop("pydantic_only", False)
         if self.pydantic_only and self.primary_key:
-            raise ModelDefinitionError('Primary key column cannot be pydantic only.')
+            raise ModelDefinitionError("Primary key column cannot be pydantic only.")
 
     @property
     def is_required(self) -> bool:
-        return not self.nullable and not self.has_default and not self.is_auto_primary_key
+        return (
+            not self.nullable and not self.has_default and not self.is_auto_primary_key
+        )
 
     @property
     def default_value(self) -> Any:
@@ -81,16 +88,19 @@ class BaseField:
     def get_constraints(self) -> Optional[List]:
         return []
 
-    def expand_relationship(self, value, child) -> Any:
+    def expand_relationship(self, value: Any, child: "Model") -> Any:
         return value
 
 
 class String(BaseField):
     __type__ = str
 
-    def __init__(self, *args, **kwargs):
-        assert 'length' in kwargs, 'length is required'
-        self.length = kwargs.pop('length')
+    def __init__(self, *args: Any, **kwargs: Any) -> None:
+        if "length" not in kwargs:
+            raise ModelDefinitionError(
+                "Param length is required for String model field."
+            )
+        self.length = kwargs.pop("length")
         super().__init__(*args, **kwargs)
 
     def get_column_type(self) -> sqlalchemy.Column:
@@ -163,27 +173,41 @@ class BigInteger(BaseField):
 class Decimal(BaseField):
     __type__ = decimal.Decimal
 
-    def __init__(self, *args, **kwargs):
-        assert 'precision' in kwargs, 'precision is required'
-        assert 'length' in kwargs, 'length is required'
-        self.length = kwargs.pop('length')
-        self.precision = kwargs.pop('precision')
+    def __init__(self, *args: Any, **kwargs: Any) -> None:
+        if "length" not in kwargs or "precision" not in kwargs:
+            raise ModelDefinitionError(
+                "Params length and precision are required for Decimal model field."
+            )
+        self.length = kwargs.pop("length")
+        self.precision = kwargs.pop("precision")
         super().__init__(*args, **kwargs)
 
     def get_column_type(self) -> sqlalchemy.Column:
         return sqlalchemy.DECIMAL(self.length, self.precision)
 
 
-def create_dummy_instance(fk: Type['Model'], pk: int = None) -> 'Model':
+def create_dummy_instance(fk: Type["Model"], pk: int = None) -> "Model":
     init_dict = {fk.__pkname__: pk or -1}
-    init_dict = {**init_dict, **{k: create_dummy_instance(v.to)
-                                 for k, v in fk.__model_fields__.items()
-                                 if isinstance(v, ForeignKey) and not v.nullable and not v.virtual}}
+    init_dict = {
+        **init_dict,
+        **{
+            k: create_dummy_instance(v.to)
+            for k, v in fk.__model_fields__.items()
+            if isinstance(v, ForeignKey) and not v.nullable and not v.virtual
+        },
+    }
     return fk(**init_dict)
 
 
 class ForeignKey(BaseField):
-    def __init__(self, to, name: str = None, related_name: str = None, nullable: bool = True, virtual: bool = False):
+    def __init__(
+        self,
+        to: Type["Model"],
+        name: str = None,
+        related_name: str = None,
+        nullable: bool = True,
+        virtual: bool = False,
+    ) -> None:
         super().__init__(nullable=nullable, name=name)
         self.virtual = virtual
         self.related_name = related_name
@@ -201,11 +225,16 @@ class ForeignKey(BaseField):
         to_column = self.to.__model_fields__[self.to.__pkname__]
         return to_column.get_column_type()
 
-    def expand_relationship(self, value, child) -> Union['Model', List['Model']]:
+    def expand_relationship(
+        self, value: Any, child: "Model"
+    ) -> Union["Model", List["Model"]]:
         if not isinstance(value, (self.to, dict, int, str, list)) or (
-                isinstance(value, orm.models.Model) and not isinstance(value, self.to)):
+            isinstance(value, orm.models.Model) and not isinstance(value, self.to)
+        ):
             raise RelationshipInstanceError(
-                'Relationship model can be build only from orm.Model, dict and integer or string (pk).')
+                "Relationship model can be build only from orm.Model, "
+                "dict and integer or string (pk)."
+            )
         if isinstance(value, list) and not isinstance(value, self.to):
             model = [self.expand_relationship(val, child) for val in value]
             return model
@@ -217,19 +246,27 @@ class ForeignKey(BaseField):
         else:
             model = create_dummy_instance(fk=self.to, pk=value)
 
-        child_model_name = self.related_name or child.__class__.__name__.lower() + 's'
-        model._orm_relationship_manager.add_relation(model.__class__.__name__.lower(),
-                                                     child.__class__.__name__.lower(),
-                                                     model, child, virtual=self.virtual)
+        child_model_name = self.related_name or child.__class__.__name__.lower() + "s"
+        model._orm_relationship_manager.add_relation(
+            model.__class__.__name__.lower(),
+            child.__class__.__name__.lower(),
+            model,
+            child,
+            virtual=self.virtual,
+        )
 
-        if child_model_name not in model.__fields__ \
-                and child.__class__.__name__.lower() not in model.__fields__:
-            model.__fields__[child_model_name] = ModelField(name=child_model_name,
-                                                            type_=Optional[child.__pydantic_model__],
-                                                            model_config=child.__pydantic_model__.__config__,
-                                                            class_validators=child.__pydantic_model__.__validators__)
-            model.__model_fields__[child_model_name] = ForeignKey(child.__class__,
-                                                                  name=child_model_name,
-                                                                  virtual=True)
+        if (
+            child_model_name not in model.__fields__
+            and child.__class__.__name__.lower() not in model.__fields__
+        ):
+            model.__fields__[child_model_name] = ModelField(
+                name=child_model_name,
+                type_=Optional[child.__pydantic_model__],
+                model_config=child.__pydantic_model__.__config__,
+                class_validators=child.__pydantic_model__.__validators__,
+            )
+            model.__model_fields__[child_model_name] = ForeignKey(
+                child.__class__, name=child_model_name, virtual=True
+            )
 
         return model

orm/helpers.py

@@ -1,26 +0,0 @@
-from typing import Union, Set, Dict  # pragma no cover
-
-
-class Excludable:  # pragma no cover
-
-    @staticmethod
-    def get_excluded(exclude: Union[Set, Dict, None], key: str = None):
-        # print(f'checking excluded for {key}', exclude)
-        if isinstance(exclude, dict):
-            if isinstance(exclude.get(key, {}), dict) and '__all__' in exclude.get(key, {}).keys():
-                return exclude.get(key).get('__all__')
-            return exclude.get(key, {})
-        return exclude
-
-    @staticmethod
-    def is_excluded(exclude: Union[Set, Dict, None], key: str = None):
-        if exclude is None:
-            return False
-        to_exclude = Excludable.get_excluded(exclude, key)
-        # print(f'to exclude for current key = {key}', to_exclude)
-
-        if isinstance(to_exclude, Set):
-            return key in to_exclude
-        elif to_exclude is ...:
-            return True
-        return False

orm/models.py

@@ -2,35 +2,39 @@ import copy
 import inspect
 import json
 import uuid
-from typing import Any, List, Type, TYPE_CHECKING, Optional, TypeVar, Tuple
-from typing import Set, Dict
+from typing import Any, List, Optional, TYPE_CHECKING, Tuple, Type, TypeVar
+from typing import Callable, Dict, Set
 
 import databases
-import pydantic
-import sqlalchemy
-from pydantic import BaseModel, BaseConfig, create_model
 
 import orm.queryset as qry
 from orm.exceptions import ModelDefinitionError
 from orm.fields import BaseField, ForeignKey
 from orm.relations import RelationshipManager
 
+import pydantic
+from pydantic import BaseConfig, BaseModel, create_model
+
+import sqlalchemy
+
 relationship_manager = RelationshipManager()
 
 
 def parse_pydantic_field_from_model_fields(object_dict: dict) -> Dict[str, Tuple]:
-    pydantic_fields = {field_name: (
-        base_field.__type__,
-        ... if base_field.is_required else base_field.default_value
-    )
+    pydantic_fields = {
+        field_name: (
+            base_field.__type__,
+            ... if base_field.is_required else base_field.default_value,
+        )
         for field_name, base_field in object_dict.items()
-        if isinstance(base_field, BaseField)}
+        if isinstance(base_field, BaseField)
+    }
     return pydantic_fields
 
 
-def sqlalchemy_columns_from_model_fields(name: str, object_dict: Dict, tablename: str) -> Tuple[Optional[str],
-                                                                                                List[sqlalchemy.Column],
-                                                                                                Dict[str, BaseField]]:
+def sqlalchemy_columns_from_model_fields(
+    name: str, object_dict: Dict, tablename: str
+) -> Tuple[Optional[str], List[sqlalchemy.Column], Dict[str, BaseField]]:
     pkname: Optional[str] = None
     columns: List[sqlalchemy.Column] = []
     model_fields: Dict[str, BaseField] = {}
@@ -42,9 +46,16 @@ def sqlalchemy_columns_from_model_fields(name: str, object_dict: Dict, tablename
                 if field.primary_key:
                     pkname = field_name
                 if isinstance(field, ForeignKey):
-                    reverse_name = field.related_name or field.to.__name__.lower().title() + '_' + name.lower() + 's'
-                    relation_name = name.lower().title() + '_' + field.to.__name__.lower()
-                    relationship_manager.add_relation_type(relation_name, reverse_name, field, tablename)
+                    reverse_name = (
+                        field.related_name
+                        or field.to.__name__.lower().title() + "_" + name.lower() + "s"
+                    )
+                    relation_name = (
+                        name.lower().title() + "_" + field.to.__name__.lower()
+                    )
+                    relationship_manager.add_relation_type(
+                        relation_name, reverse_name, field, tablename
+                    )
                 columns.append(field.get_column(field_name))
     return pkname, columns, model_fields
 
@@ -57,9 +68,7 @@ def get_pydantic_base_orm_config() -> Type[BaseConfig]:
 
 
 class ModelMetaclass(type):
-    def __new__(
-            mcs: type, name: str, bases: Any, attrs: dict
-    ) -> type:
+    def __new__(mcs: type, name: str, bases: Any, attrs: dict) -> type:
         new_model = super().__new__(  # type: ignore
             mcs, name, bases, attrs
         )
@@ -71,25 +80,29 @@ class ModelMetaclass(type):
         metadata = attrs["__metadata__"]
 
         # sqlalchemy table creation
-        pkname, columns, model_fields = sqlalchemy_columns_from_model_fields(name, attrs, tablename)
-        attrs['__table__'] = sqlalchemy.Table(tablename, metadata, *columns)
-        attrs['__columns__'] = columns
-        attrs['__pkname__'] = pkname
+        pkname, columns, model_fields = sqlalchemy_columns_from_model_fields(
+            name, attrs, tablename
+        )
+        attrs["__table__"] = sqlalchemy.Table(tablename, metadata, *columns)
+        attrs["__columns__"] = columns
+        attrs["__pkname__"] = pkname
 
         if not pkname:
-            raise ModelDefinitionError('Table has to have a primary key.')
+            raise ModelDefinitionError("Table has to have a primary key.")
 
         # pydantic model creation
         pydantic_fields = parse_pydantic_field_from_model_fields(attrs)
-        pydantic_model = create_model(name, __config__=get_pydantic_base_orm_config(), **pydantic_fields)
-        attrs['__pydantic_fields__'] = pydantic_fields
-        attrs['__pydantic_model__'] = pydantic_model
-        attrs['__fields__'] = copy.deepcopy(pydantic_model.__fields__)
-        attrs['__signature__'] = copy.deepcopy(pydantic_model.__signature__)
-        attrs['__annotations__'] = copy.deepcopy(pydantic_model.__annotations__)
-        attrs['__model_fields__'] = model_fields
+        pydantic_model = create_model(
+            name, __config__=get_pydantic_base_orm_config(), **pydantic_fields
+        )
+        attrs["__pydantic_fields__"] = pydantic_fields
+        attrs["__pydantic_model__"] = pydantic_model
+        attrs["__fields__"] = copy.deepcopy(pydantic_model.__fields__)
+        attrs["__signature__"] = copy.deepcopy(pydantic_model.__signature__)
+        attrs["__annotations__"] = copy.deepcopy(pydantic_model.__annotations__)
+        attrs["__model_fields__"] = model_fields
 
-        attrs['_orm_relationship_manager'] = relationship_manager
+        attrs["_orm_relationship_manager"] = relationship_manager
 
         new_model = super().__new__(  # type: ignore
             mcs, name, bases, attrs
@@ -99,7 +112,8 @@ class ModelMetaclass(type):
 
 
 class Model(list, metaclass=ModelMetaclass):
-    # Model inherits from list in order to be treated as request.Body parameter in fastapi routes,
+    # Model inherits from list in order to be treated as
+    # request.Body parameter in fastapi routes,
     # inheriting from pydantic.BaseModel causes metaclass conflicts
     __abstract__ = True
     if TYPE_CHECKING:  # pragma no cover
@@ -115,17 +129,20 @@ class Model(list, metaclass=ModelMetaclass):
 
     objects = qry.QuerySet()
 
-    def __init__(self, *args, **kwargs) -> None:
+    def __init__(self, *args: Any, **kwargs: Any) -> None:
         self._orm_id: str = uuid.uuid4().hex
         self._orm_saved: bool = False
         self.values: Optional[BaseModel] = None
 
         if "pk" in kwargs:
             kwargs[self.__pkname__] = kwargs.pop("pk")
-        kwargs = {k: self.__model_fields__[k].expand_relationship(v, self) for k, v in kwargs.items()}
+        kwargs = {
+            k: self.__model_fields__[k].expand_relationship(v, self)
+            for k, v in kwargs.items()
+        }
         self.values = self.__pydantic_model__(**kwargs)
 
-    def __del__(self):
+    def __del__(self) -> None:
         self._orm_relationship_manager.deregister(self)
 
     def __setattr__(self, key: str, value: Any) -> None:
@@ -138,20 +155,24 @@ class Model(list, metaclass=ModelMetaclass):
 
             value = self.__model_fields__[key].expand_relationship(value, self)
 
-            relation_key = self.__class__.__name__.title() + '_' + key
+            relation_key = self.__class__.__name__.title() + "_" + key
             if not self._orm_relationship_manager.contains(relation_key, self):
                 setattr(self.values, key, value)
         else:
             super().__setattr__(key, value)
 
     def __getattribute__(self, key: str) -> Any:
-        if key != '__fields__' and key in self.__fields__:
-            relation_key = self.__class__.__name__.title() + '_' + key
+        if key != "__fields__" and key in self.__fields__:
+            relation_key = self.__class__.__name__.title() + "_" + key
             if self._orm_relationship_manager.contains(relation_key, self):
                 return self._orm_relationship_manager.get(relation_key, self)
 
             item = getattr(self.values, key, None)
-            if item is not None and self.is_conversion_to_json_needed(key) and isinstance(item, str):
+            if (
+                item is not None
+                and self.is_conversion_to_json_needed(key)
+                and isinstance(item, str)
+            ):
                 try:
                     item = json.loads(item)
                 except TypeError:  # pragma no cover
@@ -159,30 +180,41 @@ class Model(list, metaclass=ModelMetaclass):
             return item
         return super().__getattribute__(key)
 
-    def __eq__(self, other):
+    def __eq__(self, other: "Model") -> bool:
         return self.values.dict() == other.values.dict()
 
-    def __same__(self, other):
-        assert self.__class__ == other.__class__
+    def __same__(self, other: "Model") -> bool:
+        if self.__class__ != other.__class__:
+            return False
         return self._orm_id == other._orm_id or (
-                self.values is not None and other.values is not None and self.pk == other.pk)
+            self.values is not None and other.values is not None and self.pk == other.pk
+        )
 
-    def __repr__(self):  # pragma no cover
+    def __repr__(self) -> str:  # pragma no cover
         return self.values.__repr__()
 
     @classmethod
-    def from_row(cls, row, select_related: List = None, previous_table: str = None) -> 'Model':
+    def from_row(
+        cls,
+        row: sqlalchemy.engine.ResultProxy,
+        select_related: List = None,
+        previous_table: str = None,
+    ) -> "Model":
 
         item = {}
         select_related = select_related or []
 
-        table_prefix = cls._orm_relationship_manager.resolve_relation_join(previous_table, cls.__table__.name)
+        table_prefix = cls._orm_relationship_manager.resolve_relation_join(
+            previous_table, cls.__table__.name
+        )
         previous_table = cls.__table__.name
         for related in select_related:
             if "__" in related:
                 first_part, remainder = related.split("__", 1)
                 model_cls = cls.__model_fields__[first_part].to
-                child = model_cls.from_row(row, select_related=[remainder], previous_table=previous_table)
+                child = model_cls.from_row(
+                    row, select_related=[remainder], previous_table=previous_table
+                )
                 item[first_part] = child
             else:
                 model_cls = cls.__model_fields__[related].to
@@ -191,7 +223,9 @@ class Model(list, metaclass=ModelMetaclass):
 
         for column in cls.__table__.columns:
             if column.name not in item:
-                item[column.name] = row[f'{table_prefix + "_" if table_prefix else ""}{column.name}']
+                item[column.name] = row[
+                    f'{table_prefix + "_" if table_prefix else ""}{column.name}'
+                ]
 
         return cls(**item)
 
@@ -200,7 +234,7 @@ class Model(list, metaclass=ModelMetaclass):
     #     return cls.__pydantic_model__.validate(value=value)
 
     @classmethod
-    def __get_validators__(cls):  # pragma no cover
+    def __get_validators__(cls) -> Callable:  # pragma no cover
         yield cls.__pydantic_model__.validate
 
     # @classmethod
@@ -211,11 +245,11 @@ class Model(list, metaclass=ModelMetaclass):
         return self.__model_fields__.get(column_name).__type__ == pydantic.Json
 
     @property
-    def pk(self):
+    def pk(self) -> str:
         return getattr(self.values, self.__pkname__)
 
     @pk.setter
-    def pk(self, value):
+    def pk(self, value: Any) -> None:
         setattr(self.values, self.__pkname__, value)
 
     @property
@@ -229,7 +263,9 @@ class Model(list, metaclass=ModelMetaclass):
             if isinstance(nested_model, list):
                 dict_instance[field] = [x.dict() for x in nested_model]
             else:
-                dict_instance[field] = nested_model.dict() if nested_model is not None else {}
+                dict_instance[field] = (
+                    nested_model.dict() if nested_model is not None else {}
+                )
         return dict_instance
 
     def from_dict(self, value_dict: Dict) -> None:
@@ -245,16 +281,22 @@ class Model(list, metaclass=ModelMetaclass):
     def extract_related_names(cls) -> Set:
         related_names = set()
         for name, field in cls.__fields__.items():
-            if inspect.isclass(field.type_) and issubclass(field.type_, pydantic.BaseModel):
+            if inspect.isclass(field.type_) and issubclass(
+                field.type_, pydantic.BaseModel
+            ):
                 related_names.add(name)
         return related_names
 
     def extract_model_db_fields(self) -> Dict:
         self_fields = self.extract_own_model_fields()
-        self_fields = {k: v for k, v in self_fields.items() if k in self.__table__.columns}
+        self_fields = {
+            k: v for k, v in self_fields.items() if k in self.__table__.columns
+        }
         for field in self.extract_related_names():
             if getattr(self, field) is not None:
-                self_fields[field] = getattr(getattr(self, field), self.__model_fields__[field].to.__pkname__)
+                self_fields[field] = getattr(
+                    getattr(self, field), self.__model_fields__[field].to.__pkname__
+                )
         return self_fields
 
     async def save(self) -> int:
@@ -264,7 +306,7 @@ class Model(list, metaclass=ModelMetaclass):
         expr = self.__table__.insert()
         expr = expr.values(**self_fields)
         item_id = await self.__database__.execute(expr)
-        setattr(self, 'pk', item_id)
+        self.pk = item_id
         return item_id
 
     async def update(self, **kwargs: Any) -> int:
@@ -274,8 +316,11 @@ class Model(list, metaclass=ModelMetaclass):
 
         self_fields = self.extract_model_db_fields()
         self_fields.pop(self.__pkname__)
-        expr = self.__table__.update().values(**self_fields).where(
-            self.pk_column == getattr(self, self.__pkname__))
+        expr = (
+            self.__table__.update()
+            .values(**self_fields)
+            .where(self.pk_column == getattr(self, self.__pkname__))
+        )
         result = await self.__database__.execute(expr)
         return result
 
@@ -285,7 +330,7 @@ class Model(list, metaclass=ModelMetaclass):
         result = await self.__database__.execute(expr)
         return result
 
-    async def load(self) -> 'Model':
+    async def load(self) -> "Model":
         expr = self.__table__.select().where(self.pk_column == self.pk)
         row = await self.__database__.fetch_one(expr)
         self.from_dict(dict(row))

orm/queryset.py

@@ -1,11 +1,14 @@
-from typing import List, TYPE_CHECKING, Type, NamedTuple
+from typing import Any, List, NamedTuple, TYPE_CHECKING, Tuple, Type, Union
 
-import sqlalchemy
-from sqlalchemy import text
+import databases
 
 import orm
 from orm import ForeignKey
-from orm.exceptions import NoMatch, MultipleMatches
+from orm.exceptions import MultipleMatches, NoMatch
+from orm.fields import BaseField
+
+import sqlalchemy
+from sqlalchemy import text
 
 if TYPE_CHECKING:  # pragma no cover
     from orm.models import Model
@@ -24,17 +27,23 @@ FILTER_OPERATORS = {
 
 
 class JoinParameters(NamedTuple):
-    prev_model: Type['Model']
+    prev_model: Type["Model"]
     previous_alias: str
     from_table: str
-    model_cls: Type['Model']
+    model_cls: Type["Model"]
 
 
 class QuerySet:
-    ESCAPE_CHARACTERS = ['%', '_']
+    ESCAPE_CHARACTERS = ["%", "_"]
 
-    def __init__(self, model_cls: Type['Model'] = None, filter_clauses: List = None, select_related: List = None,
-                 limit_count: int = None, offset: int = None):
+    def __init__(
+        self,
+        model_cls: Type["Model"] = None,
+        filter_clauses: List = None,
+        select_related: List = None,
+        limit_count: int = None,
+        offset: int = None,
+    ) -> None:
         self.model_cls = model_cls
         self.filter_clauses = [] if filter_clauses is None else filter_clauses
         self._select_related = [] if select_related is None else select_related
@@ -48,47 +57,77 @@ class QuerySet:
         self.columns = None
         self.order_bys = None
 
-    def __get__(self, instance, owner):
+    def __get__(self, instance: "QuerySet", owner: Type["Model"]) -> "QuerySet":
         return self.__class__(model_cls=owner)
 
     @property
-    def database(self):
+    def database(self) -> databases.Database:
         return self.model_cls.__database__
 
     @property
-    def table(self):
+    def table(self) -> sqlalchemy.Table:
         return self.model_cls.__table__
 
-    def prefixed_columns(self, alias, table):
-        return [text(f'{alias}_{table.name}.{column.name} as {alias}_{column.name}')
-                for column in table.columns]
+    def prefixed_columns(self, alias: str, table: sqlalchemy.Table) -> List[text]:
+        return [
+            text(f"{alias}_{table.name}.{column.name} as {alias}_{column.name}")
+            for column in table.columns
+        ]
 
-    def prefixed_table_name(self, alias, name):
-        return text(f'{name} {alias}_{name}')
+    def prefixed_table_name(self, alias: str, name: str) -> text:
+        return text(f"{name} {alias}_{name}")
 
-    def on_clause(self, from_table, to_table, previous_alias, alias, to_key, from_key):
-        return text(f'{alias}_{to_table}.{to_key}='
-                    f'{previous_alias + "_" if previous_alias else ""}{from_table}.{from_key}')
+    def on_clause(
+        self,
+        from_table: str,
+        to_table: str,
+        previous_alias: str,
+        alias: str,
+        to_key: str,
+        from_key: str,
+    ) -> text:
+        return text(
+            f"{alias}_{to_table}.{to_key}="
+            f'{previous_alias + "_" if previous_alias else ""}{from_table}.{from_key}'
+        )
 
-    def build_join_parameters(self, part, join_params: JoinParameters):
+    def build_join_parameters(
+        self, part: str, join_params: JoinParameters
+    ) -> JoinParameters:
         model_cls = join_params.model_cls.__model_fields__[part].to
         to_table = model_cls.__table__.name
 
-        alias = model_cls._orm_relationship_manager.resolve_relation_join(join_params.from_table, to_table)
+        alias = model_cls._orm_relationship_manager.resolve_relation_join(
+            join_params.from_table, to_table
+        )
         if alias not in self.used_aliases:
             if join_params.prev_model.__model_fields__[part].virtual:
-                to_key = next((v for k, v in model_cls.__model_fields__.items()
-                               if isinstance(v, ForeignKey) and v.to == join_params.prev_model), None).name
+                to_key = next(
+                    (
+                        v
+                        for k, v in model_cls.__model_fields__.items()
+                        if isinstance(v, ForeignKey) and v.to == join_params.prev_model
+                    ),
+                    None,
+                ).name
                 from_key = model_cls.__pkname__
             else:
                 to_key = model_cls.__pkname__
                 from_key = part
 
-            on_clause = self.on_clause(join_params.from_table, to_table, join_params.previous_alias, alias, to_key,
-                                       from_key)
+            on_clause = self.on_clause(
+                join_params.from_table,
+                to_table,
+                join_params.previous_alias,
+                alias,
+                to_key,
+                from_key,
+            )
             target_table = self.prefixed_table_name(alias, to_table)
-            self.select_from = sqlalchemy.sql.outerjoin(self.select_from, target_table, on_clause)
-            self.order_bys.append(text(f'{alias}_{to_table}.{model_cls.__pkname__}'))
+            self.select_from = sqlalchemy.sql.outerjoin(
+                self.select_from, target_table, on_clause
+            )
+            self.order_bys.append(text(f"{alias}_{to_table}.{model_cls.__pkname__}"))
             self.columns.extend(self.prefixed_columns(alias, model_cls.__table__))
             self.used_aliases.append(alias)
 
@@ -98,44 +137,76 @@ class QuerySet:
         return JoinParameters(prev_model, previous_alias, from_table, model_cls)
 
     @staticmethod
-    def field_is_a_foreign_key_and_no_circular_reference(field, field_name, rel_part) -> bool:
+    def field_is_a_foreign_key_and_no_circular_reference(
+        field: BaseField, field_name: str, rel_part: str
+    ) -> bool:
         return isinstance(field, ForeignKey) and field_name not in rel_part
 
-    def field_qualifies_to_deeper_search(self, field, parent_virtual, nested, rel_part) -> bool:
+    def field_qualifies_to_deeper_search(
+        self, field: ForeignKey, parent_virtual: bool, nested: bool, rel_part: str
+    ) -> bool:
         prev_part_of_related = "__".join(rel_part.split("__")[:-1])
-        partial_match = any([x.startswith(prev_part_of_related) for x in self._select_related])
+        partial_match = any(
+            [x.startswith(prev_part_of_related) for x in self._select_related]
+        )
         already_checked = any([x.startswith(rel_part) for x in self.auto_related])
-        return ((field.virtual and parent_virtual) or (partial_match and not already_checked)) or not nested
+        return (
+            (field.virtual and parent_virtual)
+            or (partial_match and not already_checked)
+        ) or not nested
 
-    def extract_auto_required_relations(self, join_params: JoinParameters,
-                                        rel_part: str = '', nested: bool = False, parent_virtual: bool = False):
+    def extract_auto_required_relations(
+        self,
+        join_params: JoinParameters,
+        rel_part: str = "",
+        nested: bool = False,
+        parent_virtual: bool = False,
+    ) -> None:
         for field_name, field in join_params.prev_model.__model_fields__.items():
-            if self.field_is_a_foreign_key_and_no_circular_reference(field, field_name, rel_part):
-                rel_part = field_name if not rel_part else rel_part + '__' + field_name
+            if self.field_is_a_foreign_key_and_no_circular_reference(
+                field, field_name, rel_part
+            ):
+                rel_part = field_name if not rel_part else rel_part + "__" + field_name
                 if not field.nullable:
                     if rel_part not in self._select_related:
                         self.auto_related.append("__".join(rel_part.split("__")[:-1]))
-                    rel_part = ''
-                elif self.field_qualifies_to_deeper_search(field, parent_virtual, nested, rel_part):
-                    join_params = JoinParameters(field.to, join_params.previous_alias,
-                                                 join_params.from_table, join_params.prev_model)
-                    self.extract_auto_required_relations(join_params=join_params,
-                                                         rel_part=rel_part, nested=True, parent_virtual=field.virtual)
+                    rel_part = ""
+                elif self.field_qualifies_to_deeper_search(
+                    field, parent_virtual, nested, rel_part
+                ):
+                    join_params = JoinParameters(
+                        field.to,
+                        join_params.previous_alias,
+                        join_params.from_table,
+                        join_params.prev_model,
+                    )
+                    self.extract_auto_required_relations(
+                        join_params=join_params,
+                        rel_part=rel_part,
+                        nested=True,
+                        parent_virtual=field.virtual,
+                    )
                 else:
-                    rel_part = ''
+                    rel_part = ""
 
-    def build_select_expression(self):
+    def build_select_expression(self) -> sqlalchemy.sql.select:
         self.columns = list(self.table.columns)
-        self.order_bys = [text(f'{self.table.name}.{self.model_cls.__pkname__}')]
+        self.order_bys = [text(f"{self.table.name}.{self.model_cls.__pkname__}")]
         self.select_from = self.table
 
         for key in self.model_cls.__model_fields__:
-            if not self.model_cls.__model_fields__[key].nullable \
-                    and isinstance(self.model_cls.__model_fields__[key], orm.fields.ForeignKey) \
-                    and key not in self._select_related:
+            if (
+                not self.model_cls.__model_fields__[key].nullable
+                and isinstance(
+                    self.model_cls.__model_fields__[key], orm.fields.ForeignKey
+                )
+                and key not in self._select_related
+            ):
                 self._select_related = [key] + self._select_related
 
-        start_params = JoinParameters(self.model_cls, '', self.table.name, self.model_cls)
+        start_params = JoinParameters(
+            self.model_cls, "", self.table.name, self.model_cls
+        )
         self.extract_auto_required_relations(start_params)
         if self.auto_related:
             new_joins = []
@@ -146,7 +217,9 @@ class QuerySet:
             self._select_related.sort(key=lambda item: (-len(item), item))
 
         for item in self._select_related:
-            join_parameters = JoinParameters(self.model_cls, '', self.table.name, self.model_cls)
+            join_parameters = JoinParameters(
+                self.model_cls, "", self.table.name, self.model_cls
+            )
 
             for part in item.split("__"):
                 join_parameters = self.build_join_parameters(part, join_parameters)
@@ -180,7 +253,7 @@ class QuerySet:
 
         return expr
 
-    def filter(self, **kwargs):
+    def filter(self, **kwargs: Any) -> "QuerySet":
         filter_clauses = self.filter_clauses
         select_related = list(self._select_related)
 
@@ -189,7 +262,7 @@ class QuerySet:
             kwargs[pk_name] = kwargs.pop("pk")
 
         for key, value in kwargs.items():
-            table_prefix = ''
+            table_prefix = ""
             if "__" in key:
                 parts = key.split("__")
 
@@ -215,9 +288,13 @@ class QuerySet:
                     # against which the comparison is being made.
                     previous_table = model_cls.__tablename__
                     for part in related_parts:
-                        current_table = model_cls.__model_fields__[part].to.__tablename__
-                        table_prefix = model_cls._orm_relationship_manager.resolve_relation_join(previous_table,
-                                                                                                 current_table)
+                        current_table = model_cls.__model_fields__[
+                            part
+                        ].to.__tablename__
+                        manager = model_cls._orm_relationship_manager
+                        table_prefix = manager.resolve_relation_join(
+                            previous_table, current_table
+                        )
                         model_cls = model_cls.__model_fields__[part].to
                         previous_table = current_table
 
@@ -236,25 +313,32 @@ class QuerySet:
             has_escaped_character = False
 
             if op in ["contains", "icontains"]:
-                has_escaped_character = any(c for c in self.ESCAPE_CHARACTERS
-                                            if c in value)
+                has_escaped_character = any(
+                    c for c in self.ESCAPE_CHARACTERS if c in value
+                )
                 if has_escaped_character:
                     # enable escape modifier
                     for char in self.ESCAPE_CHARACTERS:
-                        value = value.replace(char, f'\\{char}')
+                        value = value.replace(char, f"\\{char}")
                 value = f"%{value}%"
 
             if isinstance(value, orm.Model):
                 value = value.pk
 
             clause = getattr(column, op_attr)(value)
-            clause.modifiers['escape'] = '\\' if has_escaped_character else None
+            clause.modifiers["escape"] = "\\" if has_escaped_character else None
 
-            clause_text = str(clause.compile(dialect=self.model_cls.__database__._backend._dialect,
-                                             compile_kwargs={"literal_binds": True}))
-            alias = f'{table_prefix}_' if table_prefix else ''
-            aliased_name = f'{alias}{table.name}.{column.name}'
-            clause_text = clause_text.replace(f'{table.name}.{column.name}', aliased_name)
+            clause_text = str(
+                clause.compile(
+                    dialect=self.model_cls.__database__._backend._dialect,
+                    compile_kwargs={"literal_binds": True},
+                )
+            )
+            alias = f"{table_prefix}_" if table_prefix else ""
+            aliased_name = f"{alias}{table.name}.{column.name}"
+            clause_text = clause_text.replace(
+                f"{table.name}.{column.name}", aliased_name
+            )
             clause = text(clause_text)
 
             filter_clauses.append(clause)
@@ -264,10 +348,10 @@ class QuerySet:
             filter_clauses=filter_clauses,
             select_related=select_related,
             limit_count=self.limit_count,
-            offset=self.query_offset
+            offset=self.query_offset,
         )
 
-    def select_related(self, related):
+    def select_related(self, related: Union[List, Tuple, str]) -> "QuerySet":
         if not isinstance(related, (list, tuple)):
             related = [related]
 
@@ -277,7 +361,7 @@ class QuerySet:
             filter_clauses=self.filter_clauses,
             select_related=related,
             limit_count=self.limit_count,
-            offset=self.query_offset
+            offset=self.query_offset,
         )
 
     async def exists(self) -> bool:
@@ -290,25 +374,25 @@ class QuerySet:
         expr = sqlalchemy.func.count().select().select_from(expr)
         return await self.database.fetch_val(expr)
 
-    def limit(self, limit_count: int):
+    def limit(self, limit_count: int) -> "QuerySet":
         return self.__class__(
             model_cls=self.model_cls,
             filter_clauses=self.filter_clauses,
             select_related=self._select_related,
             limit_count=limit_count,
-            offset=self.query_offset
+            offset=self.query_offset,
         )
 
-    def offset(self, offset: int):
+    def offset(self, offset: int) -> "QuerySet":
         return self.__class__(
             model_cls=self.model_cls,
             filter_clauses=self.filter_clauses,
             select_related=self._select_related,
             limit_count=self.limit_count,
-            offset=offset
+            offset=offset,
         )
 
-    async def first(self, **kwargs):
+    async def first(self, **kwargs: Any) -> "Model":
         if kwargs:
             return await self.filter(**kwargs).first()
 
@@ -316,7 +400,7 @@ class QuerySet:
         if rows:
             return rows[0]
 
-    async def get(self, **kwargs):
+    async def get(self, **kwargs: Any) -> "Model":
         if kwargs:
             return await self.filter(**kwargs).get()
 
@@ -329,7 +413,7 @@ class QuerySet:
             raise MultipleMatches()
         return self.model_cls.from_row(rows[0], select_related=self._select_related)
 
-    async def all(self, **kwargs):
+    async def all(self, **kwargs: Any) -> List["Model"]:
         if kwargs:
             return await self.filter(**kwargs).all()
 
@@ -345,7 +429,7 @@ class QuerySet:
         return result_rows
 
     @classmethod
-    def merge_result_rows(cls, result_rows):
+    def merge_result_rows(cls, result_rows: List["Model"]) -> List["Model"]:
         merged_rows = []
         for index, model in enumerate(result_rows):
             if index > 0 and model.pk == result_rows[index - 1].pk:
@@ -355,30 +439,45 @@ class QuerySet:
         return merged_rows
 
     @classmethod
-    def merge_two_instances(cls, one: 'Model', other: 'Model'):
+    def merge_two_instances(cls, one: "Model", other: "Model") -> "Model":
         for field in one.__model_fields__.keys():
             # print(field, one.dict(), other.dict())
-            if isinstance(getattr(one, field), list) and not isinstance(getattr(one, field), orm.models.Model):
+            if isinstance(getattr(one, field), list) and not isinstance(
+                getattr(one, field), orm.models.Model
+            ):
                 setattr(other, field, getattr(one, field) + getattr(other, field))
             elif isinstance(getattr(one, field), orm.models.Model):
                 if getattr(one, field).pk == getattr(other, field).pk:
-                    setattr(other, field, cls.merge_two_instances(getattr(one, field), getattr(other, field)))
+                    setattr(
+                        other,
+                        field,
+                        cls.merge_two_instances(
+                            getattr(one, field), getattr(other, field)
+                        ),
+                    )
         return other
 
-    async def create(self, **kwargs):
+    async def create(self, **kwargs: Any) -> "Model":
 
         new_kwargs = dict(**kwargs)
 
         # Remove primary key when None to prevent not null constraint in postgresql.
         pkname = self.model_cls.__pkname__
         pk = self.model_cls.__model_fields__[pkname]
-        if pkname in new_kwargs and new_kwargs.get(pkname) is None and (pk.nullable or pk.autoincrement):
+        if (
+            pkname in new_kwargs
+            and new_kwargs.get(pkname) is None
+            and (pk.nullable or pk.autoincrement)
+        ):
             del new_kwargs[pkname]
 
         # substitute related models with their pk
         for field in self.model_cls.extract_related_names():
             if field in new_kwargs and new_kwargs.get(field) is not None:
-                new_kwargs[field] = getattr(new_kwargs.get(field), self.model_cls.__model_fields__[field].to.__pkname__)
+                new_kwargs[field] = getattr(
+                    new_kwargs.get(field),
+                    self.model_cls.__model_fields__[field].to.__pkname__,
+                )
 
         # Build the insert expression.
         expr = self.table.insert()

orm/relations.py

@@ -2,7 +2,7 @@ import pprint
 import string
 import uuid
 from random import choices
-from typing import TYPE_CHECKING, List
+from typing import Dict, List, TYPE_CHECKING, Union
 from weakref import proxy
 
 from orm.fields import ForeignKey
@@ -11,40 +11,58 @@ if TYPE_CHECKING:  # pragma no cover
     from orm.models import Model
 
 
-def get_table_alias():
-    return ''.join(choices(string.ascii_uppercase, k=2)) + uuid.uuid4().hex[:4]
+def get_table_alias() -> str:
+    return "".join(choices(string.ascii_uppercase, k=2)) + uuid.uuid4().hex[:4]
 
 
-def get_relation_config(relation_type: str, table_name: str, field: ForeignKey):
+def get_relation_config(
+    relation_type: str, table_name: str, field: ForeignKey
+) -> Dict[str, str]:
     alias = get_table_alias()
-    config = {'type': relation_type,
-              'table_alias': alias,
-              'source_table': table_name if relation_type == 'primary' else field.to.__tablename__,
-              'target_table': field.to.__tablename__ if relation_type == 'primary' else table_name
-              }
+    config = {
+        "type": relation_type,
+        "table_alias": alias,
+        "source_table": table_name
+        if relation_type == "primary"
+        else field.to.__tablename__,
+        "target_table": field.to.__tablename__
+        if relation_type == "primary"
+        else table_name,
+    }
     return config
 
 
 class RelationshipManager:
-
-    def __init__(self):
+    def __init__(self) -> None:
         self._relations = dict()
 
-    def add_relation_type(self, relations_key: str, reverse_key: str, field: ForeignKey, table_name: str):
-        print(relations_key, reverse_key)
+    def add_relation_type(
+        self, relations_key: str, reverse_key: str, field: ForeignKey, table_name: str
+    ) -> None:
         if relations_key not in self._relations:
-            self._relations[relations_key] = get_relation_config('primary', table_name, field)
+            self._relations[relations_key] = get_relation_config(
+                "primary", table_name, field
+            )
         if reverse_key not in self._relations:
-            self._relations[reverse_key] = get_relation_config('reverse', table_name, field)
+            self._relations[reverse_key] = get_relation_config(
+                "reverse", table_name, field
+            )
 
-    def deregister(self, model: 'Model'):
+    def deregister(self, model: "Model") -> None:
         # print(f'deregistering {model.__class__.__name__}, {model._orm_id}')
         for rel_type in self._relations.keys():
             if model.__class__.__name__.lower() in rel_type.lower():
                 if model._orm_id in self._relations[rel_type]:
                     del self._relations[rel_type][model._orm_id]
 
-    def add_relation(self, parent_name: str, child_name: str, parent: 'Model', child: 'Model', virtual: bool = False):
+    def add_relation(
+        self,
+        parent_name: str,
+        child_name: str,
+        parent: "Model",
+        child: "Model",
+        virtual: bool = False,
+    ) -> None:
         parent_id = parent._orm_id
         child_id = child._orm_id
         if virtual:
@@ -53,12 +71,18 @@ class RelationshipManager:
             child, parent = parent, proxy(child)
         else:
             child = proxy(child)
-        parents_list = self._relations[parent_name.lower().title() + '_' + child_name + 's'].setdefault(parent_id, [])
+        parents_list = self._relations[
+            parent_name.lower().title() + "_" + child_name + "s"
+        ].setdefault(parent_id, [])
         self.append_related_model(parents_list, child)
-        children_list = self._relations[child_name.lower().title() + '_' + parent_name].setdefault(child_id, [])
+        children_list = self._relations[
+            child_name.lower().title() + "_" + parent_name
+        ].setdefault(child_id, [])
         self.append_related_model(children_list, parent)
 
-    def append_related_model(self, relations_list: List['Model'], model: 'Model'):
+    def append_related_model(
+        self, relations_list: List["Model"], model: "Model"
+    ) -> None:
         for x in relations_list:
             try:
                 if x.__same__(model):
@@ -68,26 +92,26 @@ class RelationshipManager:
 
         relations_list.append(model)
 
-    def contains(self, relations_key: str, object: 'Model'):
+    def contains(self, relations_key: str, object: "Model") -> bool:
         if relations_key in self._relations:
             return object._orm_id in self._relations[relations_key]
         return False
 
-    def get(self, relations_key: str, object: 'Model'):
+    def get(self, relations_key: str, object: "Model") -> Union["Model", List["Model"]]:
         if relations_key in self._relations:
             if object._orm_id in self._relations[relations_key]:
-                if self._relations[relations_key]['type'] == 'primary':
+                if self._relations[relations_key]["type"] == "primary":
                     return self._relations[relations_key][object._orm_id][0]
                 return self._relations[relations_key][object._orm_id]
 
     def resolve_relation_join(self, from_table: str, to_table: str) -> str:
         for k, v in self._relations.items():
-            if v['source_table'] == from_table and v['target_table'] == to_table:
-                return self._relations[k]['table_alias']
-        return ''
+            if v["source_table"] == from_table and v["target_table"] == to_table:
+                return self._relations[k]["table_alias"]
+        return ""
 
-    def __str__(self):  # pragma no cover
+    def __str__(self) -> str:  # pragma no cover
         return pprint.pformat(self._relations, indent=4, width=1)
 
-    def __repr__(self):  # pragma no cover
+    def __repr__(self) -> str:  # pragma no cover
         return self.__str__()

tests/test_model_definition.py

@@ -109,6 +109,22 @@ def test_setting_pk_column_as_pydantic_only_in_model_definition():
             test = fields.Integer(name='test12', primary_key=True, pydantic_only=True)
 
 
+def test_decimal_error_in_model_definition():
+    with pytest.raises(ModelDefinitionError):
+        class ExampleModel2(Model):
+            __tablename__ = "example4"
+            __metadata__ = metadata
+            test = fields.Decimal(name='test12', primary_key=True)
+
+
+def test_string_error_in_model_definition():
+    with pytest.raises(ModelDefinitionError):
+        class ExampleModel2(Model):
+            __tablename__ = "example4"
+            __metadata__ = metadata
+            test = fields.String(name='test12', primary_key=True)
+
+
 def test_json_conversion_in_model():
     with pytest.raises(pydantic.ValidationError):
         ExampleModel(test_json=datetime.datetime.now(), test=1, test_string='test', test_bool=True)