Specifying CASCADE Mode
The CASCADE keyword in DROP TABLE removes related database objects, including referential constraints built on the table, views defined on the table, and any violations and diagnostics tables associated with the table.
If the table is the supertable in an inheritance hierarchy, CASCADE drops all of the subtables as well as the supertable.
The CASCADE mode is the default mode of the DROP TABLE statement. You can also specify this mode explicitly with the CASCADE keyword.