# Building references

There are three ways to create reference values in your XML files.

## Using a known Object ID

If you know the Object ID of an object in the FIM service, you can reference the Object ID directly. The following example shows adding the built-in administrator to the membership of a set

```xml
<AttributeOperation operation="add" name="ExplicitMember">7fb2b853-24f0-4498-9534-4e10589723c4</AttributeOperation>
```

## Referencing another ResourceOperation element

If you have a resource defined in your XML file as a [ResourceOperation element](https://docs.lithnet.io/resource-management-powershell/configuration/operations-element/resourceoperation-element), you can reference the ResourceObject instead, and the tool will automatically populate the reference attribute with the correct Object ID using an [AttributeOperation](https://docs.lithnet.io/resource-management-powershell/configuration/operations-element/attributeoperations-element/attributeoperation-element) with a type of `xmlref`

```xml
<!-- Create the workflow to reference -->
<ResourceOperation operation="Add Update" resourceType="WorkflowDefinition" id="demoWorkflowDefinition">
      <AnchorAttributes>
        <AnchorAttribute>DisplayName</AnchorAttribute>
      </AnchorAttributes>
      <AttributeOperations>
        <AttributeOperation operation="replace" name="DisplayName">___Demo Workflow Definition</AttributeOperation>
        <AttributeOperation operation="replace" name="XOML" type="file">.\Templates\WFDemo.xml</AttributeOperation>
        <AttributeOperation operation="replace" name="RequestPhase">Action</AttributeOperation>
        <AttributeOperation operation="replace" name="RunOnPolicyUpdate">false</AttributeOperation>
      </AttributeOperations>
</ResourceOperation>

<!-- Update the MPR that references the workflow -->
<ResourceOperation operation="Update" resourceType="ManagementPolicyRule" id="demoMPR">
      <AnchorAttributes>
        <AnchorAttribute>DisplayName</AnchorAttribute>
      </AnchorAttributes>
      <AttributeOperations>
        <AttributeOperation operation="none" name="DisplayName">___Demo MPR - Triggers Workflow</AttributeOperation>
        <AttributeOperation operation="replace" name="ActionWorkflowDefinition" type="xmlref">demoWorkflowDefinition</AttributeOperation>
       </AttributeOperations>
</ResourceOperation>
```

## Referencing an object that exists in the FIM Service

If you know that an object exists in the FIM service (such as an object-of-box object), you can reference it directly using the `reference` type on the [AttributeOperation element](https://docs.lithnet.io/resource-management-powershell/configuration/operations-element/attributeoperations-element/attributeoperation-element). The following example sets the ExplicitMember attribute of one object to a reference to the "Administrators" built-in set.

```xml
<AttributeOperation operation="add" name="ExplicitMember" type="reference">Set|DisplayName|Administrators</AttributeOperation>
```

## Deferencing an XML ResourceOperation

You can dereference a ResourceOperation and get one of the attributes contained in the object using a special variable syntax using the format `##xmlref:<xmlrefid>:<attribute name>##`. In the following example we define a Workflow definition with its known display name

```xml
<ResourceOperation operation="None" resourceType="WorkflowDefinition" id="demoWorkflowDefinition">
      <AnchorAttributes>
        <AnchorAttribute>DisplayName</AnchorAttribute>
      </AnchorAttributes>
      <AttributeOperations>
        <AttributeOperation operation="none" name="DisplayName">___Demo Workflow Definition</AttributeOperation>
      </AttributeOperations>
</ResourceOperations>
```

Which can then be referenced by attribute operations within other ResourceOperations

```xml
<AttributeOperation operation="replace" name="Description">Triggers the "##xmlref:demoWorkflowDefinition:DisplayName##" workflow</AttributeOperation>
```