# 3.8.4. Directed acyclic graph type definitions

{% hint style="warning" %}
All acyclic graph type relationships between Geo-Objects (instance data) must be done through the [GeoPrism Registry API](https://georegistry-api-docs.geoprism.net/#tag/ETL/operation/importEdgeJson).
{% endhint %}

## 3.8.4.1. XSD definition <a href="#xsd-definition.2" id="xsd-definition.2"></a>

```
<xs:complexType name="dag">
    <xs:attribute name="code" type="xs:string" use="required" />
    <xs:attribute name="label" type="xs:string" use="required" />
    <xs:attribute name="description" type="xs:string" use="optional" />
  </xs:complexType>
```

Example:

```
<dag
    code="FLOWS_INTO"
    label="Flows Into (MOH)"
    description=" This DAG links bodies of water which flow into other bodies of water"/>  
```