ADD_SUBSET_RULES for LOB

Question

Oracle 11g:
I need to add a subset_rule for eg: (column * (some forumula)) = result. But the problem is that the table has LOB columns. And subset rule documentation says:
Also, the specified table cannot have any LOB, LONG, or LONG RAW columns currently or in the future.I am currently in the fix as to what I can do to get rid of that row in capture process.

Answer 1

Just a quick feedback on this "empty Array".
The documentation is not cristal clear but I am convinced it refers to the array of LCR
into the ANYDATA and not an array of ANAYDATA. Nevertherless, I have explored the ARRAY of anydata
using an action context associated with STREAMS$_ARRAY_TRANS_FUNCTION(as opposed
to STREAMS$_TRANS_FUNCTION) which allow the return of many ANYDATA for a single
one ANYDATA input and managed to procuded empty ANYDATA.
I did not found any reference or example to help me in Google or Metalink
so I published my findings here as it may serve further people in search of info about usage of
STREAMS$_ARRAY_TRANS_FUNCTION
Here is a type of function that could allow this.
The context must be associated with this function _ARRAY
declare
  v_dml_rule_name VARCHAR2(30);
  v_ddl_rule_name VARCHAR2(30);
  action_ctx   sys.re$nv_list;
  ac_name      varchar2(30) := 'STREAMS$_ARRAY_TRANS_FUNCTION';       <-- note the '_ARRAY'
BEGIN
    action_ctx := sys.re$nv_list(sys.re$nv_array());
    action_ctx.add_pair( ac_name, sys.anydata.convertvarchar2('strmadmin.DML_TRANSFORM_FUNCT'));
  DBMS_STREAMS_ADM.ADD_TABLE_RULES(
      table_name         => 'STRMADMIN.TEST_DROP_COL',
      streams_type       => 'capture',
      streams_name       => 'TEST_CAPTURE',
      queue_name         => 'STRMADMIN.TEST_CAPTURE_Q',
      include_dml        => true,
      include_ddl        => false,
      include_tagged_lcr => false,
      inclusion_rule     => true,
      dml_rule_name      => v_dml_rule_name ,
      ddl_rule_name      => v_ddl_rule_name );
    dbms_rule_adm.alter_rule( rule_name    => v_dml_rule_name, action_context => action_ctx);
END;
/This create a variation of Streams transformation function with is reported
into as 'ONE to MANY' transformation into DBA_STREAMS_TRANSFORM_FUNCTION
col TRANSFORM_FUNCTION_NAME for a50
col VALUE_TYPE for a30
select RULE_OWNER, RULE_NAME, VALUE_TYPE, TRANSFORM_FUNCTION_NAME, CUSTOM_TYPE
       from DBA_STREAMS_TRANSFORM_FUNCTION;The function becomes more complicated to adapt to this multi-anydata dimension:
RULE_OWNER     RULE_NAME        VALUE_TYPE                     TRANSFORM_FUNCTION_NAME                            CUSTOM_TYPE
STRMADMIN      TEST_DROP_COL44  SYS.VARCHAR2                   strmadmin.DML_TRANSFORM_FUNCT                      ONE TO MANY
CREATE OR REPLACE function DML_TRANSFORM_FUNCT( inAnyData in SYS.AnyData)
RETURN sys.STREAMS$_ANYDATA_ARRAY IS
    ret          pls_integer;
    typelcr      VARCHAR2(61);
    lcrOut       SYS.LCR$_ROW_RECORD;
    var_any      anydata ;
    v_num        number ;
    v_lcr        SYS.LCR$_ROW_RECORD;
    v_arr        SYS.STREAMS$_ANYDATA_ARRAY;
BEGIN
   v_arr:=SYS.STREAMS$_ANYDATA_ARRAY();
   typelcr := inAnyData.getTypeName();
   IF typelcr = 'SYS.LCR$_ROW_RECORD' THEN
      -- Typecast AnyData to LCR$_ROW_RECORD
      ret := inAnyData.GetObject(lcrOut);
      IF lcrOut.get_object_owner() = 'STRMADMIN' THEN
         IF lcrOut.get_object_name() = 'TEST_DROP_COL' THEN
            lcrOut.delete_column(column_name=>'DATA_LONG');
            -- check if we don't need to discard this LCR
            var_any := lcrOut.get_Value('NEW','MYKEY') ;
            if var_any is not null then
               ret:=var_any.getnumber(v_num);
               if v_num = 4 then
                   -- We do nothing but return a null ANYDATA
                   RETURN v_arr ;
               end if;
            end if;
            -- this LCR is not to be discared, then let's apply our transformation
            lcrOut.set_value('new','DATA_SHORT',anydata.convertvarchar2('PP CONVERTED') );
            v_arr.extend;
            v_arr(1) :=SYS.AnyData.ConvertObject(lcrOut);
            RETURN v_arr;
         END IF;
      END IF;
    END IF;
    -- if we are here then the LCR is not a row
        -- or the row was not one bound for transformation,
        -- so we alter nothing
    v_arr.extend;
    v_arr(1) :=inAnyData ;
    RETURN v_arr;
END;
/Alas, when the value of MYKEY is null the function produces
a null ANYDATA which is explicitely forbidden :
http://download.oracle.com/docs/cd/B28359_01/appdev.111/b28419/d_streams_adm.htm#CDEJFBHD
  Logminer                        Captured                   Capture
        ID Capture user           Start scn   CHANGE_TIME    Type       Rule set Name   Neg rule set    Status
        41 STRMADMIN             110500477205 02-07 13:54:48 LOCAL      RULESET$_28                     ABORTED
                                                                                                            Last remote
                                                       Last system    Last scn      Delay      Last scn      confirmed      Delay
Capture name           QUEUE_NAME                          scn         Scanned     Scanned     enqueued     scn Applied  Enq-Applied
TEST_CAPTURE           TEST_CAPTURE_Q                                                                       110503647881
no rows selected
ORA-26747: The one-to-many transformation function strmadmin.DML_TRANSFORM_FUNCT
encountered the following error:  return of NULL anydata array element not allowedOf course I could generate the header
    v_lcr        SYS.LCR$_ROW_RECORD;
               ret:=var_any.getnumber(v_num);
               if v_num = 4 then
                   -- lcrOut.set_value('new','DATA_SHORT',anydata.convertvarchar2('v_num = '||to_char(v_num)) );
                   v_lcr :=  SYS.LCR$_ROW_RECORD.CONSTRUCT (
                                     source_database_name=>SYS_CONTEXT('USERENV','DB_NAME'),
                                     command_type=>lcrOut.get_command_type(),
                                     object_owner=>lcrOut.GET_OBJECT_OWNER(),
                                     object_name=>lcrOut.GET_OBJECT_NAME() );
                   v_arr.extend;
                   v_arr(1) := SYS.AnyData.ConvertObject(v_lcr);
                   RETURN v_arr ;
               end if;But the LCR is create with and sent, not discarded as expected despite
that there are no columns and it fails miserably at apply site.
That's all, and that's a failure. Maybe somebody else will have a better inspiration.
Edited by: bpolarsk on Jul 2, 2009 5:57 AM