Drop default primary key is another is defined (#812) (#851)

pynecone/model.py

@@ -1,5 +1,7 @@
 """Database built into Pynecone."""
 
+from typing import Optional
+
 import sqlmodel
 
 from pynecone.base import Base
@@ -25,7 +27,19 @@ class Model(Base, sqlmodel.SQLModel):
     """Base class to define a table in the database."""
 
     # The primary key for the table.
-    id: int = sqlmodel.Field(primary_key=True)
+    id: Optional[int] = sqlmodel.Field(primary_key=True)
+
+    def __init_subclass__(cls):
+        """Drop the default primary key field if any primary key field is defined."""
+        non_default_primary_key_fields = [
+            field_name
+            for field_name, field in cls.__fields__.items()
+            if field_name != "id" and getattr(field.field_info, "primary_key", None)
+        ]
+        if non_default_primary_key_fields:
+            cls.__fields__.pop("id", None)
+
+        super().__init_subclass__()
 
     def dict(self, **kwargs):
         """Convert the object to a dictionary.

tests/test_model.py

@@ -0,0 +1,51 @@
+import pytest
+import sqlmodel
+
+from pynecone.model import Model
+
+
+@pytest.fixture
+def model_default_primary() -> Model:
+    """Returns a model object with no defined primary key.
+
+    Returns:
+        Model: Model object.
+    """
+
+    class ChildModel(Model):
+        name: str
+
+    return ChildModel(name="name")  # type: ignore
+
+
+@pytest.fixture
+def model_custom_primary() -> Model:
+    """Returns a model object with a custom primary key.
+
+    Returns:
+        Model: Model object.
+    """
+
+    class ChildModel(Model):
+        custom_id: int = sqlmodel.Field(default=None, primary_key=True)
+        name: str
+
+    return ChildModel(name="name")  # type: ignore
+
+
+def test_default_primary_key(model_default_primary):
+    """Test that if a primary key is not defined a default is added.
+
+    Args:
+        model_default_primary: Fixture.
+    """
+    assert "id" in model_default_primary.__class__.__fields__
+
+
+def test_custom_primary_key(model_custom_primary):
+    """Test that if a primary key is defined no default key is added.
+
+    Args:
+        model_custom_primary: Fixture.
+    """
+    assert "id" not in model_custom_primary.__class__.__fields__