feat: add soft delete mixin and session

[letsdeepchat]

Adds SoftDeleteMixin and SoftDeleteSession to support soft deletes with optional hard delete bypass.

[github-actions]

📝 Docs preview

Last commit 8f42544 at: https://0e0527df.sqlmodel.pages.dev

[letsdeepchat]

Summary

Adds soft delete support to SQLModel via two new classes:

• SoftDeleteMixin — adds a deleted_at: Optional[datetime] column to any model
• SoftDeleteSession — overrides delete() to set deleted_at instead of removing the row. Accepts hard_delete=True to bypass and do a real delete.

Usage

from sqlmodel import SQLModel, Field, create_engine
from sqlmodel.soft_delete import SoftDeleteMixin
from sqlmodel.soft_delete_session import SoftDeleteSession as Session

class Hero(SoftDeleteMixin, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str

with Session(engine) as session:
    session.delete(hero)              # soft delete — sets deleted_at
    session.delete(hero, hard_delete=True)  # real delete

Changes

• sqlmodel/soft_delete.py — SoftDeleteMixin class
• sqlmodel/soft_delete_session.py — SoftDeleteSession class
• tests/test_session_delete.py — 3 tests: soft delete, hard delete bypass, plain model unaffected

Notes

• Models not using SoftDeleteMixin are completely unaffected
• Works with both SQLAlchemy 1.4 and 2.x
• No changes to existing session or model internals

[svlandeg]

Could you have a look into the failing CI? I'll put this in draft in the meantime.

[github-actions]

Heads-up: this will be closed in 3 days unless there's new activity.

[github-actions]

As this PR has been waiting for the original user for a while but seems to be inactive, it's now going to be closed. But if there's anyone interested, feel free to create a new PR.

[Sakura0122]

Hi @letsdeepchat , I’m currently learning SQLModel and was looking for soft delete support, then found this PR.

From what I understand, this PR adds SoftDeleteMixin and makes session.delete() set deleted_at, but it doesn’t seem to automatically filter normal SELECT queries with deleted_at IS NULL.

Would you still be interested in continuing this PR and adding query filtering support as well? Thanks!

[ifhover]

Hi @letsdeepchat , I’m currently learning SQLModel and was looking for soft delete support, then found this PR.

From what I understand, this PR adds SoftDeleteMixin and makes session.delete() set deleted_at, but it doesn’t seem to automatically filter normal SELECT queries with deleted_at IS NULL.

Would you still be interested in continuing this PR and adding query filtering support as well? Thanks!

Hi @Sakura0122,

Just my two cents as a passerby: this PR already represents a community contribution, and implementing automatic query filtering for soft-deleted rows is a fairly substantial feature on its own.

If that behavior is important for your use case, it might be worth opening a separate issue or even contributing a dedicated PR, rather than expecting the original author to continue extending a closed PR.

Thanks to everyone involved for improving SQLModel.