Drop Statement inside a PL SQL

is it ok to do a Drop inside a PL SQL.

whats wrong with this SQL

I am trying to drop all users. The problem is in the drop user username cascase statement

connect sys/abcsds@1.1.1.1 as sysdba
exec dbms_output.enable(1000000)开发者_C百科;
set serveroutput on
DECLARE
BEGIN
for rec in (select username from dba_users where username LIKE 'S%' AND username NOT LIKE 'SY%') loop
dbms_output.put_line(to_char(rec.username));
dbms_sql.execute('drop user rec.username cascade');
end loop;
END;
.
run;
exit;

You can use DDL in a loop but you'll have to build the string since you can't bind object names.

For example:

DECLARE
   l_ddl VARCHAR2(1000);
BEGIN
   FOR rec IN (SELECT username
                 FROM dba_users
                WHERE username LIKE 'S%'
                  AND username NOT LIKE 'SY%') LOOP
      l_ddl := 'drop user '|| rec.username ||' cascade';
      dbms_output.put_line(l_ddl);
      EXECUTE IMMEDIATE (l_ddl);
   END LOOP;
END;

Be careful though, DDL is not transactional in Oracle (it performs a commit before and after) and thus you won't be able to rollback any changes.