Displaying Resources Based on the Absence of Fields

When you want to offer resource links by matching a field in the coverage database (TITLE, for example) only if some other field is not present in the OpenURL (ISSN, for example), use a field test of the type Check for field.

To use a Check for field test, you:

1. Create one or more field selectors.
   
   The definition of the field selector is used in the field test to identify an OpenURL element. This is the element that must be missing from the OpenURL when the Check for field test is applied. The Check for field test does not examine the value of OpenURL elements. The test evaluates only the presence or absence of the elements. Therefore, the results of regular expressions in field selectors are not used by Check for field tests.
2. Create the Check for field test.
3. Assign the Check for field test to one or more target resources.

Testing OpenURLs for the Absence of Fields

To create a field test that displays resources only if one or more elements are missing from the OpenURL:

1. Choose Data and Field Tests from the menu on the left-hand side of the WebBridge LR home page.
   
   The Data and Field Tests tab displays:
   
   
2. Choose the Create New button.
   
   The Data Field Test tab displays.
   
   
3. Enter a Name.
4. Choose Check for field.
   
   Additional parameters display:
   
   
5. Choose a field selector from the drop down menu.
6. Choose Save.
7. Assign the data test to a resource.