Hi Matt thanks for posting in the Lucid Community! At this time highlighting or shading a specific row within an ERD table isn't currently supported in Lucidchart. Our apologies for the inconvenience here - I certainly understand how this could be an important part of your diagram. Our development team is highly interested in your feedback and if you're willing to share it they would love to hear more about your use case via the Product Feedback space in this community. Thank you for your insight that helps us improve our products!

It is however possible to style individual fields within a row to edit the text by applying a style. While this does require styling the text in each cell separately you can still achieve a look that distinguishes the row as a whole. In my example below I've bolded and colored one of the rows in my ERD:

I hope this helps! Please let me know if you have additional questions. 

One way to accomplish this in leu of an integrated solution is to layer a box on top of your table filled with your color. Adjust the opacity to allow you to view the underlaying text.