DROP TABLE t1;
DROP TABLE t2;
DROP TABLE t3;
DROP TABLE t4;
DROP TABLE t5;

CREATE TABLE t1 AS SELECT * FROM dba_objects WHERE object_id IS NOT NULL;
CREATE TABLE t2 AS SELECT * FROM t1;
CREATE TABLE t3 AS SELECT * FROM t1;
CREATE TABLE t4 AS SELECT * FROM t1;
CREATE TABLE t5 AS SELECT * FROM t1;

ALTER TABLE t1 ADD PRIMARY KEY (object_id);