Request to support BLOB and treat empty_blob() defaults as NULL.

This is an example DDL in our db:
 CREATE TABLE "MTEXT"."MOMS_STACKRUN" 
   ( "STACK_NAME" VARCHAR2(40 CHAR) NOT NULL ENABLE, 
"RUN_ID" NUMBER(10,0) NOT NULL ENABLE, 
"PARENT_RUN_ID" NUMBER(10,0), 
"REPRINT_ORIG_STACK_RUNID" NUMBER(10,0), 
"STATUS" NUMBER(*,0) NOT NULL ENABLE, 
"START_TIME" DATE NOT NULL ENABLE, 
"STOP_TIME" DATE, 
"FIRST_DOC_STACK_POS" NUMBER(10,0), 
"LAST_DOC_STACK_POS" NUMBER(10,0), 
"ONLINESTACK_RUNID" NUMBER(10,0), 
"DOCUMENT_COLLECTION_COUNT" NUMBER(10,0) NOT NULL ENABLE, 
"ERROR_COUNT" NUMBER(10,0) NOT NULL ENABLE, 
"REPRINT_STACKPOS_RANGES" VARCHAR2(2000 CHAR), 
"STACK_SELECT" BLOB DEFAULT empty_blob(), 
"ERROR_MSG" VARCHAR2(256 CHAR), 
"NEXT_TIMEOUT" DATE, 
"LAST_TIMEOUT" DATE, 
"DISPLAY_NAME" VARCHAR2(40 CHAR), 
"NODE_ID" VARCHAR2(80 CHAR), 
"ONLINE_STACK_START_PARAMETERS" BLOB DEFAULT empty_blob(), 
"RESET_SPLIT_DOCS" CHAR(1 CHAR), 
"SELECT_HASHCODE" NUMBER(10,0), 
"USERINFO" VARCHAR2(32 CHAR), 
"STOP_REQUEST_TIME" DATE, 
PRIMARY KEY ("RUN_ID"));

The same could be applied to CLOB with emtpy_clob() defaults.