Currently in our (enterprise) UI, there are tables that have required selections. Typically, these tables have hundreds to thousands of objects. In one case an action is to be performed against these specific objects, and the user is required to select, at least one, in order to perform the action.
There is required asterisk next to the name of the table within the field header. Within the within the form nav itself, if a required field has not been met in that part of the form, it also indicates in the tab, with a red bar, there is an error within the category (tabs are a vertical stepper-list, the highlighted element indicates that portion of the form is active and in view).
The main difference in the design system is when a required input, or selection has not been met or contains an error, the input highlights red, and an error message appears. This pattern is less direct, and less clear for a selection in an entire table to be in error. Potentially this could be a red outline around the data table, however, I can't find a pattern like this online, or within our design system.
Another externality of calling this object table: In order to fetch the data, the user would have to have entered a URL, and a user and pw, and then the connection would have to be valid before fetching the table data. Automatically selecting the first leaf is a bit problematic as the nodes are only called and reveled when the user selects that object.