# Configuring Object References in Advanced Search

Advanced Search allows users to perform more complex queries for documents by searching within specific fields, including attachments, changing the search operator, and searching within document content. You can add up to five (5) object reference fields as filters in the advanced search dialog.

## How to Define Advanced Search Document Filters

Navigate to **Admin > Settings > Search Settings** to define the object reference fields to include as filters.

In the _Advanced Search Document Filters_ section, you can select an object reference field for each **Filter**. When you click **Save**, any filters you selected here will appear in the Advanced Search dialog on all document tabs for all users in your Vault. In the Advanced Search dialog, object reference field filters display in the order in which you add them on the **Search Settings** page.

## Rules for Defining Object Reference Field Filters

Follow the rules below when defining object reference fields as document search filters:

* Define up to five (5) object reference fields as filters.
* Select any document field that references an object.
* If an object is in a parent-child relationship, include the parent object reference field as a filter if you use the child field as a filter.
* If an object is in a parent-child relationship, remove the child object reference field as a filter before you can remove its parent.

## Automatic Filters in Clinical Operations

By default, Clinical Operations Vaults include the _Study_, _Study Country_, and _Site_ object reference fields as filters in the Advanced Search dialog. Admins can remove or update these from the **Search Settings** page.