Model only the business structure
Describe objects, fields, relationships, and a few rules in a small model language that developers can read and maintain by hand.
<root>
<merchant _name="Merchant" _module="sales" _module_key="sales"
name="Acme Shop" external_id="ACME-001" />
<order_status _name="Order Status" _module="sales" _module_key="sales"
id="id()" name="string()" code="string()" merchant="merchant(context)"
_constant="true" _identifier="code">
<_value id="1" name="Paid" code="PAID" />
<_value id="2" name="Cancelled" code="CANCELLED" />
</order_status>
<order _name="Order" _module="sales" _module_key="sales"
code="SO-2026-0001" status="order_status()" total_amount="128.50"
merchant="merchant(context)" />
<order_line _name="Order Line" _module="sales" _module_key="sales"
order="order()" sku="SKU-1001" quantity="2"
merchant="merchant(context)" />
</root>