How to update these two tables

Question

Hello,
I have two tables (in Oracle 11g R2), and have to lock certain rows in each one of them for update...
Here is the sample data and expected result after updating, please help me for update statements.
Thanks in advance!!!
drop table t1;
drop table t2;
create table t1(
t1_id     number(5) primary key,
t1_col2   varchar2(20),
t1_col3   varchar2(10),
t2_id     varchar2(5));
create table t2(
t2_id    varchar2(5) primary key,
t2_col2  varchar2(10),
t2_col3  number(2),
t1_id    number);
insert into t1 values(1, '1 - col2', 'AB', null);
insert into t1 values(2, '2 - col2', 'AB', null);
insert into t1 values(3, '3 - col2', 'AB', null);
insert into t1 values(4, '4 - col2', 'AC', null);
insert into t1 values(5, '5 - col2', 'AC', null);
insert into t1 values(6, '6 - col2', 'AC', null);
insert into t1 values(7, '7 - col2', 'AC', null);
insert into t1 values(8, '8 - col2', 'AC', null);
insert into t1 values(9, '9 - col2', 'AC', null);
insert into t1 values(10, '10 - col2', 'AC', null);
commit;
insert into t2 values('11001', 'ABC', 12, null);
insert into t2 values('11021', 'ABC', 12, null);
insert into t2 values('11022', 'ABC', 12, null);
insert into t2 values('11023', 'ABC', 12, null);
insert into t2 values('11024', 'ABC', 12, null);
insert into t2 values('11025', 'ABC', 12, null);
insert into t2 values('11030', 'ABC', 12, null);
insert into t2 values('11035', 'ABC', 12, null);
insert into t2 values('11051', 'ABC', 12, null);
insert into t2 values('11061', 'ABC', 12, null);
insert into t2 values('11071', 'ABC', 12, null);
insert into t2 values('11081', 'ABC', 11, null);
insert into t2 values('11091', 'ABC', 11, null);
commit;
declare
  cursor c1 is select *
                 from t1
                where t1_id in(select t1_id from (select t1_id from t1 where t1_col3 = 'AC' order by t1_id) where rownum <= 5)
               for update;
  cursor c2 is select *
                 from t2
                where t2_id in(select t2_id from (select t2_id from t2 where t2_col3 = 12 order by t2_id) where rownum <= 5)
               for update;
begin
  for rec_c1 in c1 loop
  end loop;
end;
The result must look like:
     T1_ID T1_COL2              T1_COL3    T2_ID
         4 4 - col2             AC         11001
         5 5 - col2             AC         11021
         6 6 - col2             AC         11022
         7 7 - col2             AC         11023
         8 8 - col2             AC         11024
T2_ID T2_COL2       T2_COL3      T1_ID
11001 ABC                12          4
11021 ABC                12          5         
11022 ABC                12          6
11023 ABC                12          7
11024 ABC                12          8

Answer 1

With the help of Bencol :-)
DECLARE
   CURSOR c1
   IS
      SELECT a.t1_id, b.t2_id
        FROM t1 a CROSS JOIN t2 b
       WHERE (a.t1_id, b.t2_id) IN (SELECT t1.t1_id, t2.t2_id
                                      FROM    (SELECT t1_id
                                                    , ROW_NUMBER () OVER (ORDER BY t1_id) t1_rn
                                                 FROM t1
                                                WHERE t1_col3 = 'AC') t1
                                           JOIN
                                              (SELECT t2_id
                                                    , ROW_NUMBER () OVER (ORDER BY t1_id) t2_rn
                                                 FROM t2
                                                WHERE t2_col3 = 12) t2
                                           ON t1.t1_rn = t2.t2_rn
                                     WHERE t1.t1_rn <= 5)
      FOR UPDATE;
BEGIN
   FOR rec_c1 IN c1
   LOOP
      UPDATE t1
         SET t2_id = rec_c1.t2_id
       WHERE t1_id = rec_c1.t1_id;
      UPDATE t2
         SET t1_id = rec_c1.t1_id
       WHERE t2_id = rec_c1.t2_id;
   END LOOP;
END;
/Regards.
Al