[Home](./index.md) > [@datashaper/schema](./schema.md) > [Constraints](./schema.constraints.md) ## Constraints interface Validation constraints for a field. Signature: ```typescript export interface Constraints ``` ## Properties | Property | Modifiers | Type | Description | | --- | --- | --- | --- | | [enum?](./schema.constraints.enum.md) | | string\[\] | (Optional) Strict list of allowed values in the column. | | [maximum?](./schema.constraints.maximum.md) | | number | (Optional) For numbers or dates, this is the maximum allowed value. | | [maxLength?](./schema.constraints.maxlength.md) | | number | (Optional) For strings or arrays, this is the maximum allowed length of values. | | [minimum?](./schema.constraints.minimum.md) | | number | (Optional) For numbers or dates, this is the minimum allowed value. | | [minLength?](./schema.constraints.minlength.md) | | number | (Optional) For strings or arrays, this is the minimum allowed length of values. | | [pattern?](./schema.constraints.pattern.md) | | string | (Optional) RegExp pattern that string values must match. | | [required?](./schema.constraints.required.md) | | boolean | (Optional) Indicates that this field is required (not nullable). | | [unique?](./schema.constraints.unique.md) | | boolean | (Optional) Indicates that every value in this column must be unique. |