How to insert null in C++ Class library

Question

I am using oo4o Class library. I am inserting arrays into the database
This is my code (it is simplified):
// C++ Code
OStartup();
oRes = m_o_Session.Open(); // m_o_Session is OSession // oRes is oresult
oRes = m_o_db.Open(m_o_Session,sSource,sUser,sPassword); // m_o_db is ODatabase
oRes = m_o_db.BeginTrans();
// the insert proccess
// Add Params
OParameterCollection oParamCol = oDB.GetParameters();
OParamArray o_NUM_INDEX_Ary = oParamCol.AddTable("xi_lv_NUM_INDEX",OPARAMETER_INVAR,OTYPE_NUMBER,10);
OParamArray o_TEXT_Ary = oParamCol.AddTable("xi_sv_TEXT",OPARAMETER_INVAR,OTYPE_VARCHAR2,10,250);
OParamArray o_NUMBER_OPT_Ary = oParamCol.AddTable("xi_dv_NUMBER_OPT",OPARAMETER_INVAR,OTYPE_NUMBER,10);
for(int i =0;i<10;i++){
o_NUM_INDEX_Ary.SetValue(i,i);
o_TEXT_Ary.SetValue("asdasd",i);
o_NUMBER_OPT_Ary.SetValue(??????,i);
oRes = oDB.ExecuteSQL("INSERT INTO GEN_TABLE_TEST_T (NUM_INDEX,TEXT,NUMBER_OPT) VALUES (:xi_lv_NUM_INDEX,:xi_sv_TEXT,:xi_dv_NUMBER_OPT)");
oParamCol.Remove("xi_lv_NUM_INDEX");
oParamCol.Remove("xi_sv_TEXT");
oParamCol.Remove("xi_dv_NUMBER_OPT");
oRes = m_o_db.CommitTrans();
oRes = m_o_db.Close();
m_o_Session.Close();
OShutdown();
my question is where I marked ?????? I want to insert null to a numeric field
I tried to put NULL instead of ?????? - does not work
I tried to put OValue initialized with null instead of ?????? - does not work
and I need to send him in the insert Sql because sometimes it does not null and i have to give him value.
thanks is advance
Yoav

Answer 1

Just create an empty OValue object:
OValue nullv; // construct null value
then call the appropriate SetValue method...
xxx.SetValue(nullv);
Should do it.