ORA Database Error Messages ORA-13798: Parameter string cannot be NULL August 24, 2015 mpbod ORA-13798: Parameter string cannot be NULL Cause: A call to GET_THRESHOLD procedure was made without a required parameter. Action: Specify a valid value for this parameter. Back to previous menu Share this:Click to email a link to a friend (Opens in new window)Click to print (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to share on Tumblr (Opens in new window)Click to share on Twitter (Opens in new window)Click to share on Pinterest (Opens in new window)Click to share on Reddit (Opens in new window)Click to share on Pocket (Opens in new window)