Added 'ON DELETE CASCADE' to foreign key instruction.

Signed-off-by: Cristiano Urban <cristiano.urban@inaf.it>

00-init.sql

@@ -49,7 +49,7 @@ CREATE TABLE location (
     storage_src_id    SMALLINT      default NULL,
     storage_dest_id   SMALLINT      default NULL,
     PRIMARY KEY (location_id),
-    FOREIGN KEY (storage_src_id) REFERENCES storage (storage_id),
+    FOREIGN KEY (storage_src_id) REFERENCES storage (storage_id) ON DELETE CASCADE,
     FOREIGN KEY (storage_dest_id) REFERENCES storage (storage_id)
 );