Field attributes

#[field(...)] is shared. Each derive reads the keys it understands.

• Validate and Schema ignore ORM keys.
• Model ignores validation keys except max_length, max_digits, and decimal_places, which become column metadata.
• Unknown keys are compile errors on Model. Schema ignores unknown keys so other derives can share the attribute.

Key names for JSON always come from Serde (rename, rename_all).

Validation and schema

Key	Validation	Schema
min_length, max_length	Characters or items	minLength / maxLength or minItems / maxItems
pattern = "regex"	Whole-value match; regex checked at expand time	pattern
email	Email format	format: email
url	—	format: uri (with #[derive(Schema)])
gt, ge, lt, le	Numeric bounds	exclusiveMinimum, minimum, exclusiveMaximum, maximum
multiple_of	Divisibility	multipleOf
validation_alias = "x"	Extra accepted input key	—
alias	—	Schema annotation
default = expr, default_factory = path	Field optional; Serde must also default it	Left out of required
strict	Strict mode for this field	—
exclude	Left out of dump	—
validator = path	Reusable after-validator	—
title, description, examples(...)	—	Annotations
max_digits, decimal_places	Documented as x- extensions unless the type is Decimal<D, P>	column metadata for Model

ORM

Key	Meaning
primary_key	Exactly one field
auto	Database-generated integer primary key
unique, index	Constraint / single-column index
column = "name"	Column name; default {field}_id for relations
db_default = …	Server-side default
auto_now_add, auto_now	DbDefault::Now
on_delete = "cascade" | "protect" | "set_null" | "set_default" | "do_nothing"	Relations only
related_name = ".."	Reverse accessor
skip	Not a column

Model-level

See Models for #[model(...)] and Validation for #[model_config(...)] and #[model_hooks].

See also

• Validation
• Models
• Pydantic v2 mapping