In reply to dhserfer:
The resource_db commands have only two lookup arguments, the scope and the name. Both are strings.
The accessor, last argument, is used only for auditting. You do not have to provide an actual argument, because it has a default value.
The config_db commands have 3 lookup arguments, the contxt, the scope and the name. The contxt is not a simple string, it is of type uvm_component. The cntxt and name argument give you more flexibility when defining what you want to set or get. Typical arguments for the contxt are ‘this’, indicating the lookup-path is a relative path from the component where the command was issued and ‘null’ indicating there is nothing above, meaning an absolute path.