Looking for a way to use custom type mappings for sqlmodel fields

[kfreezen]

First Check

• I added a very descriptive title here.
• I used the GitHub search to find a similar question 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
from sqlalchemy import TEXT

# Written in pydantic v2 code
# Option 1
class Model(SQLModel):
  model_config = ConfigDict(type_mapping={str: TEXT})

  string_field: str

# Option 2
class Model(SQLModel):
  string_field: str = Field(mapped_type=TEXT)

Description

I'm looking for a way to use TEXT instead of VARCHAR for existing database applications.

It looks like option 2 is the easier one to implement, since you don't have to change the argument list of def get_sqlalchemy_type
However, option 1 is easier for the user, since they only have to specify it once in a base model.

What do you think? I can take a stab at implementing either one--or both.

Operating System

macOS

Operating System Details

No response

SQLModel Version

0.0.16

Python Version

3.11.1

Additional Context

No response