0.0.14 - regex keyword on Field object not working (should be pattern in Pydantic v2)

[DarylStark]

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

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Example Code

from sqlmodel import Field, Relationship
from pydantic import Field as Field2

class User(SQLModel):
    fullname: str = Field(regex=r'^[A-Za-z0-9\- ]+$', max_length=128)
    fullname2: str = Field2(pattern=r'^[A-Za-z0-9\- ]+$', max_length=128)

fails = User(fullname='test', fullname2='test_failing') # Fails because it knows how to process the regex

succeeds = User(fullname='test_not_failing', fullname2='test') # Does not fail because the `regex` keyword is ignored

Description

I'm migrating from SQLModel 0.0.8 to SQLModel 0.0.14 using Pydantic 2.5.2. In SQLModel 0.0.8 I could use the regex keyword from the Field class to create a regular expression validation, but that doesn't work anymore. According to the docs of Pydantic, this should be pattern, but the Field object of SQLModel doesn't support that named argument.

Operating System

Linux

Operating System Details

Pydantic version 2.5.2 (Core = 2.14.5)

SQLModel Version

0.0.14

Python Version

3.10.13

Additional Context

No response

[MatMoore]

I can reproduce this issue as well.

As a workaround I was able to use schema_extra like this:

class User(SQLModel):
    fullname: str = Field(max_length=128, schema_extra={'pattern': r'^[A-Za-z0-9\- ]+$'})

although I'm not sure if this is completely equivalent.

If the current version of sqlmodel is targeting both pydantic 1 and pydantic 2, perhaps SQLModel's Field should use pattern as well and support regex as an alias?

[dnszero]

Thank you!

It turns out this is still the best solution in 2025 with SQLModel 0.0.24

[DarylStark]

I was unaware of the schema_extra argument. Thank you! That helps a lot!

[clembir]

It seems that the SQLModel Field class are not fully compatible with Pydantic v2 Field class.

• Some attributes are missing like alias_priority, validation_alias, serialization_alias, examples, json_schema_extra, frozen, validate_default, init_var, kw_only, strict, allow_inf_nan and union_mode.

• Some attributes need to be updated like regex which is now pattern as explained above.

• Some attributes need to be deleted because they still refer to Pydantic v1 Field class like comp, min_items, max_items, unique_items and allow_mutation.

This is not a lot of work to make the modification in the code as it's just necessary to update the Field class in the main.py file with these attributes and the appropriate annotations.

[simonryf]

Linking the PR :-)
#1231