E-R Diagram of the Geodatabase

[LubicaCverckova2]

Hello,

I have .xlm of our gedatabase. I do use X-ray for geodatabase but it doesn't show the relationships between feature classes. Is there a tool that shows the relations,E-R?

Basically, I have this but the x-ray doesn't display how the feature classes/tables are connected.

I have ArcGIS 10.3.

I appreciate your input.

Thanks.