max_length does not work in Fields

First Check

I added a very descriptive title to this issue.
I used the GitHub search to find a similar issue and didn't find it.
I searched the SQLModel documentation, with the integrated search.
I already searched in Google "How to X in SQLModel" and didn't find any information.
I already read and followed all the tutorial in the docs and didn't find an answer.
I already checked if it is not related to SQLModel but to Pydantic.
I already checked if it is not related to SQLModel but to SQLAlchemy.

Commit to Help

I commit to help with one of those options 👆

Example Code

from sqlmodel import SQLModel, Field


class Locations(SQLModel, table=True):
    LocationName: str = Field(max_length=255)

Description

When running the above code, I get a
ValueError: On field "LocationName" the following field constraints are set but not enforced: max_length

I also tried pydantic's documentation by changing the 'str' typing to constr(max_length=255) to no avail.

Operating System

Windows

Operating System Details

No response

SQLModel Version

0.0.4

Python Version

3.9.4

Additional Context

No response

Try this:

from sqlmodel import SQLModel, Field, Column, String


class Locations(SQLModel, table=True):
    LocationName: str = Field(sa_column=Column(String(255)))

This started working for some reason, genuinely not sure what resolved; maybe new version of fastapi?

How is it even related to FastAPI? SQLModel is still at version 0.0.4.

Fair point. I'm just genuinely not sure why it started working. waited a couple days, didnt even close the project, and it started working.

I ended up just leaving the max_length args in there and it seemed to start working. could not tell you why the errors earlier were consistently getting thrown.

2 years passed, is There any official solution?

@PaleNeutron

@PaleNeutron this is what worked for me when migrating the model to mysql8. Just adding the max_length field did not change the size of the varchar.

class Hero(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str = Field.Field(
        max_length=1024, sa_column=sqlalchemy.Column(sqlalchemy.String(1024))
    )

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max_length does not work in Fields #126

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max_length does not work in Fields #126

Description

First Check

Commit to Help

Example Code

Description

Operating System

Operating System Details

SQLModel Version

Python Version

Additional Context

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yasamoka commented on Oct 11, 2021

yudjinn commented on Oct 11, 2021

yasamoka commented on Oct 11, 2021

yudjinn commented on Oct 12, 2021

yudjinn commented on Oct 12, 2021

PaleNeutron commented on Jan 10, 2024

patrickwasp commented on Apr 3, 2024

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