[odb-users] Use odb.exe on window problem

[阿比]

Dear, I'm Chinese and my English is so so, hope you could understand my follow question, thank you.
  I use odb.exe on window to generate *-odb files use follow command
odb -d sqlite --generate-query --generate-schema person.hxx
then I get the sql statements in person-odb.cxx. In person-odb.cxx, the create table statement like follow:
("CREATE TABLE \"person\" (\n"
                      "  \"id\" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,\n"
                      "  \"first\" TEXT NOT NULL,\n"
                      "  \"last\" TEXT NOT NULL,\n"
                      "  \"age\" INTEGER NOT NULL)")
But I need create table IFNOTEXISTS.  Just like "CREATE TABLE  IFNOTEXISTS \"person\" ....
1. I could not found something about this settings in odb --help.
2. I could found the create statement in obd/relational/sqlite/schema.cxx like follow
struct version_table: relational::version_table, context
{
version_table (base const& x): base (x) {}


virtual void
create_table ()
{
pre_statement ();


os << "CREATE TABLE IF NOT EXISTS " << qt_ << " (" << endl
<< "  " << qn_ << " TEXT NOT NULL PRIMARY KEY," << endl
<< "  " << qv_ << " INTEGER NOT NULL," << endl
<< "  " << qm_ << " INTEGER NOT NULL)" << endl;


post_statement ();
} 
It has IF NOT EXISTS, why the generate code without?
I use odb-2.4.0-i686-windows and download from https://www.codesynthesis.com/products/odb/download.xhtml.
Thank you and wait for your reply.