✨ Automatically map dictionaries to JSON

Author: patrick91

sqlmodel/main.py

@@ -53,7 +53,7 @@
 from sqlalchemy.orm.decl_api import DeclarativeMeta
 from sqlalchemy.orm.instrumentation import is_instrumented
 from sqlalchemy.sql.schema import MetaData
-from sqlalchemy.sql.sqltypes import LargeBinary, Time, Uuid
+from sqlalchemy.sql.sqltypes import JSON, LargeBinary, Time, Uuid
 from typing_extensions import Literal, TypeAlias, deprecated, get_origin
 
 from ._compat import (  # type: ignore[attr-defined]
@@ -700,6 +700,8 @@ def get_sqlalchemy_type(field: Any) -> Any:
         )
     if issubclass(type_, uuid.UUID):
         return Uuid
+    if issubclass(type_, dict):
+        return JSON
     raise ValueError(f"{type_} has no matching SQLAlchemy type")
 
 

tests/test_dict.py

@@ -0,0 +1,80 @@
+from typing import Dict, Optional
+
+from sqlmodel import Field, Session, SQLModel, create_engine
+from typing_extensions import TypedDict
+
+
+def test_dict_maps_to_json(clear_sqlmodel):
+    class Resource(SQLModel, table=True):
+        id: Optional[int] = Field(default=None, primary_key=True)
+        name: str
+        data: dict
+
+    engine = create_engine("sqlite://")
+    SQLModel.metadata.create_all(engine)
+
+    resource = Resource(name="test", data={"key": "value", "num": 42})
+
+    with Session(engine) as session:
+        session.add(resource)
+        session.commit()
+        session.refresh(resource)
+
+        assert resource.data["key"] == "value"
+        assert resource.data["num"] == 42
+
+
+def test_typing_dict_maps_to_json(clear_sqlmodel):
+    """Test if typing.Dict type annotation works without explicit sa_type"""
+
+    class Resource(SQLModel, table=True):
+        id: Optional[int] = Field(default=None, primary_key=True)
+        name: str
+        data: Dict[str, int]
+
+    engine = create_engine("sqlite://")
+    SQLModel.metadata.create_all(engine)
+
+    resource = Resource(name="test", data={"count": 100})
+
+    with Session(engine) as session:
+        session.add(resource)
+        session.commit()
+        session.refresh(resource)
+
+        assert resource.data["count"] == 100
+
+
+class Metadata(TypedDict):
+    name: str
+    email: str
+
+
+def test_typeddict_automatic_json_mapping(clear_sqlmodel):
+    """
+    Test that TypedDict fields automatically map to JSON type.
+
+    This fixes the original error:
+    ValueError: <class 'app.models.NeonMetadata'> has no matching SQLAlchemy type
+    """
+
+    class ConnectedResource(SQLModel, table=True):
+        id: Optional[int] = Field(default=None, primary_key=True)
+        name: str
+        neon_metadata: Metadata
+
+    engine = create_engine("sqlite://")
+    SQLModel.metadata.create_all(engine)
+
+    resource = ConnectedResource(
+        name="my-resource",
+        neon_metadata={"name": "John Doe", "email": "john.doe@example.com"},
+    )
+
+    with Session(engine) as session:
+        session.add(resource)
+        session.commit()
+        session.refresh(resource)
+
+        assert resource.neon_metadata["name"] == "John Doe"
+        assert resource.neon_metadata["email"] == "john.doe@example.com"

tests/test_sqlalchemy_type_errors.py

@@ -1,4 +1,4 @@
-from typing import Any, Dict, List, Optional, Union
+from typing import List, Optional, Union
 
 import pytest
 from sqlmodel import Field, SQLModel
@@ -12,14 +12,6 @@ class Hero(SQLModel, table=True):
             tags: List[str]
 
 
-def test_type_dict_breaks() -> None:
-    with pytest.raises(ValueError):
-
-        class Hero(SQLModel, table=True):
-            id: Optional[int] = Field(default=None, primary_key=True)
-            tags: Dict[str, Any]
-
-
 def test_type_union_breaks() -> None:
     with pytest.raises(ValueError):
 

tests/test_type_mappings.py

@@ -0,0 +1,67 @@
+"""Test that Python type annotations map to correct SQLAlchemy column types"""
+
+from typing import Dict, Optional
+
+from sqlalchemy import JSON, Boolean, Date, DateTime, Float, Integer
+from sqlalchemy.sql.sqltypes import LargeBinary
+from sqlmodel import Field, SQLModel
+from sqlmodel.sql.sqltypes import AutoString
+from typing_extensions import TypedDict
+
+
+def test_dict_maps_to_json(clear_sqlmodel):
+    """Test that plain dict annotation maps to JSON column type"""
+
+    class Model(SQLModel, table=True):
+        id: Optional[int] = Field(default=None, primary_key=True)
+        data: dict
+
+    assert isinstance(Model.data.type, JSON)  # type: ignore
+
+
+def test_typing_dict_maps_to_json(clear_sqlmodel):
+    """Test that typing.Dict annotation maps to JSON column type"""
+
+    class Model(SQLModel, table=True):
+        id: Optional[int] = Field(default=None, primary_key=True)
+        data: Dict[str, int]
+
+    assert isinstance(Model.data.type, JSON)  # type: ignore
+
+
+def test_typeddict_maps_to_json(clear_sqlmodel):
+    """Test that TypedDict annotation maps to JSON column type"""
+
+    class MyDict(TypedDict):
+        name: str
+        count: int
+
+    class Model(SQLModel, table=True):
+        id: Optional[int] = Field(default=None, primary_key=True)
+        data: MyDict
+
+    assert isinstance(Model.data.type, JSON)  # type: ignore
+
+
+def test_other_type_mappings(clear_sqlmodel):
+    """Test that other common types map correctly"""
+    from datetime import date, datetime
+
+    class Model(SQLModel, table=True):
+        id: Optional[int] = Field(default=None, primary_key=True)
+        name: str
+        count: int
+        price: float
+        active: bool
+        created: datetime
+        birth_date: date
+        data_bytes: bytes
+
+    # Verify the type mappings
+    assert isinstance(Model.name.type, AutoString)  # type: ignore
+    assert isinstance(Model.count.type, Integer)  # type: ignore
+    assert isinstance(Model.price.type, Float)  # type: ignore
+    assert isinstance(Model.active.type, Boolean)  # type: ignore
+    assert isinstance(Model.created.type, DateTime)  # type: ignore
+    assert isinstance(Model.birth_date.type, Date)  # type: ignore
+    assert isinstance(Model.data_bytes.type, LargeBinary)  # type: ignore