Order of columns in the table created does not have 'id' first, despite the order in the SQLModel. Looks like it's prioritising fields with sa_column

[epicwhale]

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• I already read and followed all the tutorial in the docs and didn't find an answer.
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• I already checked if it is not related to SQLModel but to SQLAlchemy.

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Example Code

from sqlmodel import Field, SQLModel, JSON, Column, Time

class MyTable(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str
    type: str
    slug: str = Field(index=True, unique=True)
    resource_data: dict | None = Field(default=None, sa_column=Column(JSON))  # type: ignore


# ... create engine

SQLModel.metadata.create_all(engine)

Description

The CREATE table script generated for the model above ends up putting resource_data as the first column, instead of preserving the natural order of 'id' first

CREATE TABLE mytable (
     resource_data JSON,          <----- why is this the FIRST column created?
     id SERIAL NOT NULL, 
     name VARCHAR NOT NULL, 
     type VARCHAR NOT NULL, 
     slug VARCHAR NOT NULL, 
     PRIMARY KEY (id)
)

This feels unusual when I inspect my postgresql tables in a db tool like pgAdmin.

How do I ensure the table is created with the 'natural' order?

Operating System

macOS

Operating System Details

No response

SQLModel Version

0.0.8

Python Version

3.11.1

Additional Context

No response

[H-Plus-Time]

I've just encountered this problem too - it originates from the way sqlalchemy deals with a Column's _creation_order property (discussed wrt mixin column ordering at stackoverflow.com/sqlalchemy-move-mixin-columns-to-end). Because the Column() call executes first, the auto-generated Column objects always have higher _creation_order values. sa_args and sa_kwargs don't have this problem (sadly you're stuck with types detectable via get_sqlachemy_type if you use those).

My workaround ended up exploiting Column::copy and the __setattr__ override in the sqlmodel metaclass:

from sqlmodel.main import SQLModelMetaclass
from sqlmodel import SQLModel, Column

class ColumnCloningMetaclass(SQLModelMetaclass):
    def __setattr__(cls, name: str, value: Any) -> None:
        if isinstance(value, Column):
            return super().__setattr__(name, value.copy())
        return super().__setattr__(name, value)

class MyTable(SQLModel, table=True, meta=ColumnCloningMetaclass):
    id: int | None = Field(default=None, primary_key=True)
    name: str
    type: str
    slug: str = Field(index=True, unique=True)
    resource_data: dict | None = Field(default=None, sa_column=Column(JSON))

# _creation_order will match order of field declaration/annotation

Works well enough (negligible perf impact since it's at class generation time), though would be obsoleted by #436 .

[LastNever]

I've just encountered this problem too - it originates from the way sqlalchemy deals with a Column's _creation_order property (discussed wrt mixin column ordering at stackoverflow.com/sqlalchemy-move-mixin-columns-to-end). Because the Column() call executes first, the auto-generated Column objects always have higher _creation_order values. sa_args and sa_kwargs don't have this problem (sadly you're stuck with types detectable via get_sqlachemy_type if you use those).

My workaround ended up exploiting Column::copy and the __setattr__ override in the sqlmodel metaclass:

from sqlmodel.main import SQLModelMetaclass
from sqlmodel import SQLModel, Column

class ColumnCloningMetaclass(SQLModelMetaclass):
    def __setattr__(cls, name: str, value: Any) -> None:
        if isinstance(value, Column):
            return super().__setattr__(name, value.copy())
        return super().__setattr__(name, value)

class MyTable(SQLModel, table=True, meta=ColumnCloningMetaclass):
    id: int | None = Field(default=None, primary_key=True)
    name: str
    type: str
    slug: str = Field(index=True, unique=True)
    resource_data: dict | None = Field(default=None, sa_column=Column(JSON))

# _creation_order will match order of field declaration/annotation

Works well enough (negligible perf impact since it's at class generation time), though would be obsoleted by #436 .

i copy your code and run ,but its not work , resource_data in the first
---i'm sorry ,it's worked , need use 'metaclass' in python 3.10

[cout]

Is this still a problem? I cannot reproduce it (sqlmodel 0.0.18, sqlalchemy 2.0.29):

CREATE TABLE mytable (
        id INTEGER NOT NULL AUTO_INCREMENT,
        name VARCHAR(255) NOT NULL,
        type VARCHAR(255) NOT NULL,
        slug VARCHAR(255) NOT NULL,
        resource_data JSON,
        PRIMARY KEY (id)
)

[prurph]

I'm running into a similar problem where mixed-in classes have their columns added first. For example I have a Timestamps class to add timestamp columns (it has a sqlalchemy watcher to automatically touch updated_at, not pictured for simplicity)

class Timestamps:
    created_at: datetime = Field(sa_type=DateTime(), nullable=False)
    updated_at: datetime = Field(sa_type=DateTime(), nullable=False)

class MyModel(SQLModel, Timestamps, table=True)
    id: Optional[int] = Field(default=None, primary_key=True)

This generates the sql (sqlite):

CREATE TABLE mymodel (
	created_at DATETIME NOT NULL,
        updated_at DATETIME NOT NULL,
        id INTEGER NOT NULL,  -- id is below mixed in fields (other fields in MyModel would appear below this)
	PRIMARY KEY (id)
);

I tried using sa_column_kwargs={"sort_order": 1000} and things like this, but only got a warning and no effect. IMO SQLModel should offer some ability to control field ordering in the create statement.

My workaround is the following hack where I pop columns off of the Tables and then stick them back on when creating the tables.

engine = create_engine(sqlite_url)

def create_db_and_tables():
    for table in SQLModel.metadata.sorted_tables:
        try:
            created_at, updated_at = (
                table.columns.get("created_at"),
                table.columns.get("updated_at"),
            )
            table._columns.remove(created_at)
            table._columns.remove(updated_at)
            table._columns.extend((created_at, updated_at))
        except KeyError:
            pass
    SQLModel.metadata.create_all(engine)

[PradeepTammali]

Hello,

I also have the same problem as @prurph. I have also tried using sa_column_kwargs={"sort_order": 10}, I followed this sqlalchemy doc and used mapped_column(sort_order=10) but this didn't work either.

created_at: datetime = Field(
        default=datetime.now(tz=timezone.utc),
        sa_column=mapped_column(name='created_at', type_=DateTime, index=True, sort_order=10),
    )

I see in the sqlalchemy documentation for sort_order https://docs.sqlalchemy.org/en/20/orm/mapping_api.html#sqlalchemy.orm.mapped_column.params.sort_order here, that it is in version 2.0.4 but as of today I only see 2.0.34 in pypi https://pypi.org/project/SQLAlchemy/2.0.34/. So I am assuming this yet to be released or maybe I missed something.

I am running the following versions.

pydantic==2.9.0
SQLAlchemy==2.0.34
sqlmodel==0.0.22

[oYASo]

Hi!

I had the same issue as @prurph, and I solved it by changing the inheritance order.

class Timestamps:
    created_at: datetime = Field(sa_type=DateTime(), nullable=False)
    updated_at: datetime = Field(sa_type=DateTime(), nullable=False)


class IntegerSQLModel(SQLModel):
    id: Optional[int] = Field(default=None, primary_key=True)


class MyModel(Timestamps, IntegerSQLModel, table=True):
    some_file: str

As a result, the following schema is generated:

CREATE TABLE my_model (
        id SERIAL NOT NULL,
        created_at TIMESTAMP WITHOUT TIME ZONE NOT NULL,
        updated_at TIMESTAMP WITHOUT TIME ZONE NOT NULL,
        some_file VARCHAR NOT NULL,
        PRIMARY KEY (id)
)

I often use separate base classes for primary keys in the form of UUID or int, so this solution works fine for me.