Oracle SQL: repeating a process for multiple tables - sql

Question

I have Oracle 11g. I would like to 'loop' this code through multiple tables t1 is already there, but I need to do this for 4 tables (t1,t2,t3, and t4):
BEGIN
EXECUTE IMMEDIATE 'TRUNCATE TABLE t1';
EXECUTE IMMEDIATE 'DROP TABLE t1';
EXCEPTION WHEN OTHERS THEN
IF SQLCODE !=-942 THEN
RAISE;
END IF;
END;
I can change this manually, but the code then swells and I would really like to control it just once.:-) Also the tables may not be sequentially labelled. Thank you in advance.
Kate

Answer 1

Make a loop where you select the table names from dual. You could also have a table containing the names and select from this.
BEGIN
for t in
(
select 't1' as table_name from dual
union all
select 't2' as table_name from dual
union all
select 't3' as table_name from dual
union all
select 't4' as table_name from dual
)
loop
EXECUTE IMMEDIATE 'TRUNCATE TABLE ' || t.table_name;
EXECUTE IMMEDIATE 'DROP TABLE ' || t.table_name;
end loop;
EXCEPTION WHEN OTHERS THEN
IF SQLCODE !=-942 THEN
RAISE;
END IF;
END;

Answer 2

There is no need to truncate a table before you drop it, so the drop table is sufficient. Additionally, I'd add the purge modifier so that it doesn't clutter the recycle bin.
begin
for t in (select table_name from user_tables
where regexp_like(table_name, '^T[1-4]$')) loop
execute immediate 'drop table ' || t.table_name || ' purge';
end loop;
end;
/
Of course, you can drop the table in a specific procedure:
declare
procedure drop_table(t in varchar2) is begin
execute immediate 'drop table ' || t || ' purge';
exception when others then
if sqlcode != -942 then
raise;
end if;
end drop_table;
begin
drop_table('T1');
drop_table('T2');
drop_table('T3');
drop_table('T4');
end;
/