ValueError: <class 'dict'> has no matching SQLAlchemy type

[Soulbadguy54]

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Example Code

from typing import List, Optional, Dict, Any
from pydantic import BaseModel, Field, field_validator
from sqlalchemy.dialects.postgresql import JSONB
from sqlalchemy.ext.mutable import MutableDict
from sqlmodel import SQLModel

class Combo(SQLModel, table=True):
    __tablename__ = "combo"
    __table_args__ = {'schema': 'public'}

    id: Optional[int] = Field(primary_key=True)
    update_date: datetime = Field(default_factory=datetime.now, index=True)
    difficult: int
    pos_x: int
    pos_y: int
    front_pos: dict[str, float] = Field(default_factory=dict, sa_type=MutableDict.as_mutable(JSONB))
    data: dict[str, Any] = Field(default_factory=dict, sa_type=MutableDict.as_mutable(JSONB))
    # or
    # front_pos: Dict = Field(default_factory=dict, sa_type=JSONB)
    # data: Dict = Field(default_factory=dict, sa_type=JSONB)
    # or with sa_column = Column(JSONB)
    # also doesnt work:
    #     class Config:
    #    arbitrary_types_allowed = True

Description

I got exactly the same error doesnt metter which way I use.
dict or Dict, or dict[str, Any] etc
MutableDict or sa_type with just JSONB or sa_column
Everytime get the same error:

  File "C:\Users\Soulbadguy\PycharmProjects\guides\server\db\models.py", line 40, in <module>
    class Combo(SQLModel, table=True):
  File "C:\Users\Soulbadguy\PycharmProjects\guides\.venv\Lib\site-packages\sqlmodel\main.py", line 559, in __new__
    col = get_column_from_field(v)
          ^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\Soulbadguy\PycharmProjects\guides\.venv\Lib\site-packages\sqlmodel\main.py", line 708, in get_column_from_field
    sa_type = get_sqlalchemy_type(field)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\Soulbadguy\PycharmProjects\guides\.venv\Lib\site-packages\sqlmodel\main.py", line 697, in get_sqlalchemy_type
    raise ValueError(f"{type_} has no matching SQLAlchemy type")
ValueError: <class 'dict'> has no matching SQLAlchemy type

Operating System

Windows

Operating System Details

No response

SQLModel Version

0.0.22

Python Version

3.12.7

Additional Context

No response

[artemisresende]

Have you tried to use a generic sqlalchemy.sql.sqltypes.JSON type instead of sqlalchemy.dialects.postgresql.JSONB on Field.sa_column parameter? Here is an example:

from sqlalchemy.sql.schema import Column
from sqlalchemy.sql.sqltypes import JSON

class ModelWithGenericJsonColumn(SQLModel, table=True):
    id: int = Field(primary_key=True)
    d: dict[str, str] = Field(default={"key": "value"}, sa_column=Column(JSON))

Maybe would work :)