set serveroutput on
begin
FOR REC IN (SELECT table_name FROM user_tables)
LOOP
EXECUTE IMMEDIATE 'Truncate Table ' ||REC.table_name;
DBMS_OUTPUT.PUT_LINE('Table '||REC.table_name||' Truncated!');
END LOOP;
END;

SET serveroutput ON;
/
DECLARE
   /*The name of the schema that should be synchronized.*/
   Schema_Name VARCHAR2(4000) :='type target schema name here';
   /*The operation type:*/
   /*  ON -- enable foreign keys;*/
   /*  OFF -- disable foreign keys.*/
   ON_OFF VARCHAR2(4000) :='ON';
PROCEDURE CONSTRAINTS_ON_OFF
(Target_Schema_Name IN VARCHAR2, Action IN VARCHAR2:='')
IS
   sql_str VARCHAR2(4000);
   FK_name VARCHAR2(4000);
   var_action VARCHAR2(4000);
CURSOR cCur1 IS
   /*Creating the list of foreign keys that should be disabled/enabled,*/
   /*with creating a command at the same time.*/
   SELECT
      'ALTER TABLE '||OWNER||'.'||
      TABLE_NAME||' '||var_action||' CONSTRAINT '||CONSTRAINT_NAME AS sql_string,
      CONSTRAINT_NAME
   FROM
      ALL_CONSTRAINTS
   WHERE
      CONSTRAINT_TYPE='R' AND OWNER=Target_Schema_Name;
BEGIN
   IF upper(Action)='ON' THEN
       var_action :='ENABLE';
   ELSE
       var_action :='DISABLE';
   END IF;
OPEN cCur1;
   LOOP
      FETCH cCur1 INTO SQL_str,fk_name;
      EXIT WHEN cCur1%NOTFOUND;
      /*Disabling/Enabling foreign keys.*/
      EXECUTE IMMEDIATE SQL_str;
      DBMS_Output.PUT_LINE('Foreign key '||FK_name||' is '||var_action||'d');
   END LOOP;
EXCEPTION
WHEN OTHERS THEN
    BEGIN
        DBMS_Output.PUT_LINE(SQLERRM);
    END;
    CLOSE cCur1;
END;
BEGIN
    CONSTRAINTS_ON_OFF(Schema_Name,ON_OFF);
    /*specify additional calls if necessary*/
END;
/
COMMIT;
/