national_char_string_type

national_char_string_type 
      ::= 
      "national" "character" [ "(" length ")" ] 
      | "national" "char" [ "(" length ")" ] 
      | "nchar" [ "(" length ")" ] 
      | "national" "character" "varying" "(" length ")" 
      | "national" "char" "varying" "(" length ")" 
      | "nchar" "varying" "(" length ")" 

This rule is called by

-> data_type