Mixer/.agents/skills/phoenix-framework/references/ecto.md

Ecto Guidelines

• Always preload Ecto associations in queries when they'll be accessed in templates, ie a message that needs to reference the message.user.email
• Remember import Ecto.Query and other supporting modules when you write seeds.exs
• Ecto.Schema fields always use the :string type, even for :text, columns, ie: field :name, :string
• Ecto.Changeset.validate_number/2 DOES NOT SUPPORT the :allow_nil option. By default, Ecto validations only run if a change for the given field exists and the change value is not nil, so such as option is never needed
• You must use Ecto.Changeset.get_field(changeset, :field) to access changeset fields
• Fields which are set programmatically, such as user_id, must not be listed in cast calls or similar for security purposes. Instead they must be explicitly set when creating the struct
• Always invoke mix ecto.gen.migration migration_name_using_underscores when generating migration files, so the correct timestamp and conventions are applied