The ISessionObject::get_SessionID method retrieves the value of the SessionID property.
HRESULT get_SessionID(
BSTR * pbstrRet //pointer to a binary string that receives the
// SessionID value
);
You should not use the SessionID property to generate primary key values for a database application. This is because if the Web server is restarted, some SessionID values may be the same as those generated before the server was stopped. Instead, you should use an auto-increment column data type, such as IDENTITY with Microsoft SQL Server, or COUNTER with Microsoft Access.