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我正在嘗試ODB ORM，我必須堅持一個接口，所以我需要一個const對象並堅持下去。我不確定ODB API是否允許持久化一個const對象，因爲有些部分似乎已經準備好了，但它不起作用。我可以將一個const對象傳遞給ODB中的db.persist嗎？
我從GCC這裏收到此錯誤：
void OdbReportRW::write_object(const MyObject &my_object)
{
odb::core::transaction t{db->begin()};
db->persist(my_object);
t.commit();
}
這是錯誤的，我認爲它說，my_object不應該是const：
In file included from /usr/local/include/odb/database.hxx:632:0,
from odb_report.hpp:21,
from src/vcf/odb_report.cpp:18:
/usr/local/include/odb/database.txx: In instantiation of ‘typename odb::object_traits<T>::id_type odb::database::persist_(T&) [with T = const MyObject; odb::database_id DB = (odb::database_id)5u; typename odb::object_traits<T>::id_type = long unsigned int]’:
/usr/local/include/odb/database.ixx:167:45: required from ‘typename odb::object_traits<T>::id_type odb::database::persist(const T&) [with T = MyObject; typename odb::object_traits<T>::id_type = long unsigned int]’
src/vcf/odb_report.cpp:134:26: required from here
/usr/local/include/odb/database.txx:38:39: error: no matching function for call to ‘odb::object_traits_impl<MyObject, (odb::database_id)5u>::persist(odb::database&, const MyObject&)’
object_traits::persist (*this, obj);
^
/usr/local/include/odb/database.txx:38:39: note: candidate is:
In file included from src/vcf/odb_report.cpp:27:0:
my-object-error-odb.hxx:247:5: note: static void odb::access::object_traits_impl<MyObject, (odb::database_id)1u>::persist(odb::database&, odb::access::object_traits<MyObject>::object_type&)
persist (database&, object_type&);
^
my-object-odb.hxx:247:5: note: no known conversion for argument 2 from ‘const MyObject’ to ‘odb::access::object_traits<MyObject>::object_type& {aka MyObject&}’
鏗鏘同樣的錯誤，一位更多的描述：
In file included from src/vcf/odb_report.cpp:18:
In file included from inc/vcf/odb_report.hpp:21:
In file included from /usr/local/include/odb/database.hxx:632:
/usr/local/include/odb/database.txx:38:36: error: binding of reference to type 'object_type' (aka 'MyObject') to a value of type 'const MyObject' drops qualifiers
object_traits::persist (*this, obj);
^~~
/usr/local/include/odb/database.ixx:167:12: note: in instantiation of function template specialization 'odb::database::persist_<const MyObject, 5>' requested here
return persist_<const T, id_common> (obj);
^
src/vcf/odb_report.cpp:134:13: note: in instantiation of function template specialization 'odb::database::persist<MyObject>' requested here
db->persist(my_object);
^
inc/vcf/error-odb.hxx:247:37: note: passing argument to parameter here
persist (database&, object_type&);
^
然而，我可以在數據庫接口（從ODB）看到，這兩種類型的的持續提供了借鑑與const引用（和其他的指針）：
// in odb/database.hxx
template <typename T>
typename object_traits<T>::id_type
persist (T& object);
template <typename T>
typename object_traits<T>::id_type
persist (const T& object);
我看到一個類似的錯誤引發（用於find，不persist）時，有在課堂上堅持沒有默認構造函數（爲MyObject這裏），但它在那裏，所以它不是問題。我已經檢查過，默認構造函數僅在生成的代碼中生成一個額外的方法find。
它的工作除去我的write_object方法中的const說明符，但正如我所說的，我必須堅持一個接口。
任何想法堅持const對象？