Attributes

Attributes are independent schema types. Declare them once in Split-YAML, then use their generated value classes wherever an entity or relation owns them.

Declare attribute types

format: typebridge.schema/v2

attributes:
  person-id:
    value: string
  age:
    value:
      type: integer
      range: {min: 0, max: 150}
  email:
    value:
      type: string
      regex: '^[^@]+@[^@]+$'
  status:
    value:
      type: string
      values: [active, inactive]
  balance:
    value: decimal
  birthday:
    value: date
  seen-at:
    value: datetime-tz
  session-length:
    value: duration
  audit-note:
    independent: true
    value: string

The built-in value types are string, integer, double, decimal, boolean, date, datetime, datetime-tz, and duration. regex, range, and values constrain the value declaration. doc and meta attach provider documentation and metadata. independent: true permits an attribute instance to exist without an owner.

Run type-bridge schema check before generation. Invalid combinations, unsupported annotations, and scalar constraint mismatches fail in the Rust schema engine.

Generated values

=== "Python"

```python
from app_models import Age, Balance, Email
from decimal import Decimal

age = Age(36)
email = Email("ada@example.com")
balance = Balance(Decimal("12.50"))

assert age.value == 36
```

=== "TypeScript"

```ts
import { Age, Balance, Email } from "./generated/models/index.js";

const age = Age.create(36n);
const email = Email.create("ada@example.com");
const balance = Balance.create("12.50");
```

=== "Rust"

```rust
let age = Age::new(36);
let email = Email::new("ada@example.com".to_owned());
```

Integer values use Python int, JavaScript bigint, and the generated Rust integer type. Decimal and duration boundaries remain lossless strings or native language values according to the generated target API.

Generated attribute classes are projection values, not declaration bases. To rename an attribute or change its scalar/constraint contract, edit Split-YAML, review a migration, and regenerate.

Ownership is separate

An attribute declaration does not imply an owner. Add it under an entity or relation's owns facts:

entities:
  person:
    owns:
      person-id: {key: true}
      age: {card: {min: 0, max: 1}}
      email: {unique: true, card: {min: 0, max: 1}}

The generated model constructor and field token are derived from these facts. See cardinality, entities, and generated queries.