BLOB limit to 2MB

Question

I want to have a column BLOB and size limit to 2MB.
10G rel 2

Answer 1

pgoel wrote:
Adding a trigger is another option.Nope. That one doesn't work for LOBs since they can be manipulated via DBMS_LOB, which bypasses row level triggers.
One possible solution on the database side is something like
SQL> create materialized view t_mv refresh fast on commit
  2  as select id, dbms_lob.getlength(x) len from t;
Materialized view created.
SQL> alter table t_mv add constraint t_mv_chk check (len < 100);
Table altered.
SQL> insert into t values (1, lpad('x', 200, 'x'));
1 row created.
SQL> commit;
commit
ERROR at line 1:
ORA-12008: error in materialized view refresh path
ORA-02290: check constraint (TIM.T_MV_CHK) violated
SQL> insert into t values (1, lpad('x', 99, 'x'));
1 row created.
SQL> commit;
Commit complete.
SQL> declare
  2      l_clob clob;
  3  begin
  4      select x into l_clob from t where id = 1 for update;
  5      dbms_lob.writeappend(l_clob, 10000, lpad('x', 10000, 'x'));
  6  end;
  7  /
PL/SQL procedure successfully completed.
SQL> commit;
commit
ERROR at line 1:
ORA-12008: error in materialized view refresh path
ORA-02290: check constraint (TIM.T_MV_CHK) violated