No this is not the proper way. First you should consider setting this up through the access rules tab on your entity. This way is much more secure than in the xpath constraint on a datagrid, and quicker because the database management system will apply the constraint instead of the runtime.
Second, your constraint now states all users that are associated with (any) userrole. So this is not specific enough I reckon. You would need to add [Name = 'MyUserRole’] before the closing bracket if you do it like this and not through access rules.