Entity Attributes & dry-types Reference

This document covers type definitions, constraints, and default value mapping for Hanami DB Entities.

Basic dry-types Core

The standard type namespace Types is defined by the framework. Common types include:

• Types::Integer
• Types::String
• Types::Time
• Types::Bool
• Types::Float
• Types::Decimal

Coercions & Constraints

You can apply type-level constraints and validation rules to attributes:

# Enforce string format (e.g. Email regex)
attribute :email, Types::String.constrained(format: /\A[\w+\-.]+@[a-z\d\-]+(\.[a-z\d\-]+)*\.\w+\z/)

# Numeric range boundary constraints
attribute :age, Types::Integer.constrained(gt: 0)

# Set defaults and restrict to specific enums
attribute :role, Types::String.default("member").enum("admin", "member", "guest")

Handling Optional / Nullable Values

By default, an attribute requires a value matching its type. If the database allows NULL, declare it as optional:

# Correct optional string declaration
attribute :middle_name, Types::String.optional

# Handling optional timestamps
attribute :last_login_at, Types::Time.optional