# Constraint

`import { Constraint } from "destack:schema";`

Schema constraint.

```ds title="Constraint"
export newtype Constraint<T> = LengthConstraint | RangeConstraint<T> | PatternConstraint | RefinementConstraint<T>
```

[language/library/src/schema/constraint.ds:70:74](https://github.com/destack-sh/destack/blob/main/language/library/src/schema/constraint.ds#L70-L74)