SQLModel fails to create DB constraints when using Annotated types after Pydantic 2.12.0

[YuriiMotov]

Discussed in #1597

^{Originally posted by MarishLakshmanan October 8, 2025}

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Example Code

Environment:
Pydantic==2.12.0

Code:

from pydantic import StringConstraints
NonEmptyString = Annotated[str, StringConstraints(strip_whitespace=True, min_length=1)]

Class Test(SQLModel):
    id: NonEmptyString = Field(primary_key=True) # this was working fine on pydantic v2.11.9

Description

Description

After upgrading to Pydantic 2.12.0, SQLModel no longer creates database constraints (like primary keys, unqiue keys ) for fields defined using Annotated types.

Example:

from typing import Annotated
from sqlmodel import SQLModel, Field
from pydantic import StringConstraints

NonEmptyString = Annotated[str, StringConstraints()]

class Test(SQLModel, table=True):
    id: NonEmptyString = Field(primary_key=True)

Expected Behavior

The table should be created with id as an varchar and primary key

Actual Behavior

it throws an error

sqlalchemy.exc.ArgumentError: Mapper Mapper[Test(test)] could not assemble any primary key columns for mapped table 'test'

Additional notes

In case you use an unique key constraint the table will be created, you will not get any error but the unique key constraint will not be created.

Operating System

Linux

Operating System Details

No response

SQLModel Version

0.0.26

Python Version

3.13.3

Additional Context

No response

[YuriiMotov]

Test taken from #1603

from sqlmodel import Field, SQLModel
from typing_extensions import Annotated


def test_declaration_syntax_1():
    class Person1(SQLModel):
        name: str = Field(primary_key=True)

    class Person1Final(Person1, table=True):
        pass


def test_declaration_syntax_2():
    class Person2(SQLModel):
        name: Annotated[str, Field(primary_key=True)]

    class Person2Final(Person2, table=True):
        pass


def test_declaration_syntax_3():
    class Person3(SQLModel):
        name: Annotated[str, ...] = Field(primary_key=True)

    class Person3Final(Person3, table=True):
        pass

test_declaration_syntax_2 and test_declaration_syntax_3 work well with Pydantic 2.11.10, but fail with Pydantic 2.12

PRs:

• 🐛 Fix support for Annotated fields with Pydantic 2.12+ #1603
• 🐛 Fix support for Annotated fields with Pydantic 2.12+ (alternative) #1607