deferred=True which will lead to DetachedInstanceError

[vahidzhe]

Checklist

• The bug is reproducible against the latest release or master.
• There are no similar issues or pull requests to fix it yet.

Describe the bug

created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        server_default=func.now(tz=pytz.timezone('Asia/Baku')),
        deferred=True,
    )
updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        server_default=func.now(tz=pytz.timezone('Asia/Baku')),
        onupdate=func.now(tz=pytz.timezone('Asia/Baku')),
        deferred=True,
    )

In my code, when deferred=True in the created_at field, it is not possible to edit an instance of my model in the Admin panel.

raise orm_exc.DetachedInstanceError(
  sqlalchemy.orm.exc.DetachedInstanceError: Parent instance <User at 0x7f215df6ce10> is not bound to a Session; 
  deferred load operation of attribute 'created_at' cannot proceed (Background on this error at: https://sqlalche.me/e/20/bhk3)

https://docs.sqlalchemy.org/en/20/errors.html#error-bhk3

Steps to reproduce the bug

No response

Expected behavior

No response

Actual behavior

No response

Debugging material

No response

Environment

Windows 10 / ptyhon 3.11 / sqladmin 0.19

Additional context

No response

[aminalaee]

Hi,
Just a question, what is your expected behaviour here? I'm guessing you don't want to be able edit created_at and updated_at right?

In that case you can just specify form_columns and leave out columns like created_at to not be shown.

class MyAdmin(...):
    form_columns = ["column_a"]

[vahidzhe]

I used form_excluded_columns and it worked. Thanks

[vahidzhe]

@aminalaee But there may be places where it is necessary to edit the created_at field, so what can I do?

[mmzeynalli]

@aminalaee I am not opening extra issue for now, but if I have deferred field, and I add that field (in my case created_at) to the list view, then aside from SQL that fetches data, N extra SQLs are run to get deferred field:

2025-01-26 12:00:51.975 UTC [191] LOG:  statement: BEGIN
2025-01-26 13:00:51 postgres-1       | 2025-01-26 12:00:51.975 UTC [191] LOG:  statement: SELECT core_file.created_at AS core_file_created_at 
2025-01-26 13:00:51 postgres-1       |  FROM core_file 
2025-01-26 13:00:51 postgres-1       |  WHERE core_file.url = 'https://cdn.test.com/test/portfolio/b134fd3d-f20e-4169-b361-2381e82f55fc.png'
2025-01-26 13:00:51 postgres-1       | 2025-01-26 12:00:51.987 UTC [191] LOG:  statement: ROLLBACK
2025-01-26 13:00:51 postgres-1       | 2025-01-26 12:00:51.993 UTC [191] LOG:  statement: BEGIN
2025-01-26 13:00:51 postgres-1       | 2025-01-26 12:00:51.993 UTC [191] LOG:  statement: SELECT core_file.created_at AS core_file_created_at 
2025-01-26 13:00:51 postgres-1       |  FROM core_file 
2025-01-26 13:00:51 postgres-1       |  WHERE core_file.url = 'https://cdn.test.com/test/portfolio/0abcfde2-6542-4adc-80f3-e896a0ad845d.png'
2025-01-26 13:00:51 postgres-1       | 2025-01-26 12:00:51.994 UTC [191] LOG:  statement: ROLLBACK
2025-01-26 13:00:51 postgres-1       | 2025-01-26 12:00:51.999 UTC [191] LOG:  statement: BEGIN
2025-01-26 13:00:51 postgres-1       | 2025-01-26 12:00:51.999 UTC [191] LOG:  statement: SELECT core_file.created_at AS core_file_created_at 
2025-01-26 13:00:51 postgres-1       |  FROM core_file 
2025-01-26 13:00:51 postgres-1       |  WHERE core_file.url = 'https://cdn.test.com/test/portfolio/33f76a67-b992-456e-9a46-615ecfa67940.PNG'
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.002 UTC [191] LOG:  statement: ROLLBACK
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.007 UTC [191] LOG:  statement: BEGIN
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.008 UTC [191] LOG:  statement: SELECT core_file.created_at AS core_file_created_at 
2025-01-26 13:00:52 postgres-1       |  FROM core_file 
2025-01-26 13:00:52 postgres-1       |  WHERE core_file.url = 'https://cdn.test.com/test/portfolio/00be1a01-c0e9-4c48-8b7e-99ba084b9bf2.PNG'
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.009 UTC [191] LOG:  statement: ROLLBACK
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.013 UTC [191] LOG:  statement: BEGIN
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.013 UTC [191] LOG:  statement: SELECT core_file.created_at AS core_file_created_at 
2025-01-26 13:00:52 postgres-1       |  FROM core_file 
2025-01-26 13:00:52 postgres-1       |  WHERE core_file.url = 'https://cdn.test.com/test/portfolio/f804bfd6-dc7d-4424-891e-902d8bcb5dea.PNG'
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.014 UTC [191] LOG:  statement: ROLLBACK
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.019 UTC [191] LOG:  statement: BEGIN
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.019 UTC [191] LOG:  statement: SELECT core_file.created_at AS core_file_created_at 
2025-01-26 13:00:52 postgres-1       |  FROM core_file 
2025-01-26 13:00:52 postgres-1       |  WHERE core_file.url = 'https://cdn.test.com/test/portfolio/b79c9c11-6fed-4cb2-9f25-ddb316016e82.png'
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.020 UTC [191] LOG:  statement: ROLLBACK
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.024 UTC [191] LOG:  statement: BEGIN
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.025 UTC [191] LOG:  statement: SELECT core_file.created_at AS core_file_created_at 
2025-01-26 13:00:52 postgres-1       |  FROM core_file 
2025-01-26 13:00:52 postgres-1       |  WHERE core_file.url = 'https://cdn.test.com/test/portfolio/dfb3ef6a-eebe-4e72-bde5-1276376a42f8.png'
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.026 UTC [191] LOG:  statement: ROLLBACK
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.032 UTC [191] LOG:  statement: BEGIN
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.032 UTC [191] LOG:  statement: SELECT core_file.created_at AS core_file_created_at 
2025-01-26 13:00:52 postgres-1       |  FROM core_file 
2025-01-26 13:00:52 postgres-1       |  WHERE core_file.url = 'https://cdn.test.com/user/avatar/7ef57c48-af1f-4c84-b55d-61b568d2dfea_original.jpg'
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.034 UTC [191] LOG:  statement: ROLLBACK
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.039 UTC [191] LOG:  statement: BEGIN
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.040 UTC [191] LOG:  statement: SELECT core_file.created_at AS core_file_created_at 
2025-01-26 13:00:52 postgres-1       |  FROM core_file 
2025-01-26 13:00:52 postgres-1       |  WHERE core_file.url = 'https://cdn.test.com/user/avatar/9f7173f0-161c-4441-a90b-1e5880741c3b_original.jpeg'
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.042 UTC [191] LOG:  statement: ROLLBACK
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.048 UTC [191] LOG:  statement: BEGIN
2025-01-26 13:00:52 postgres-1       | 2025-01-26 12:00:52.048 UTC [191] LOG:  statement: SELECT core_file.created_at AS core_file_created_at 
2025-01-26 13:00:52 postgres-1       |  FROM core_file 
2025-01-26 13:00:52 postgres-1       |  WHERE core_file.url = 'https://cdn.test.com/user/avatar/873d599b-cac6-4a03-a017-84353162096c_original.jpg'