Oracle ODBC: get(T) caused exception "bad cast"

[330305020]

I'm using oracle ODBC. The exception "bad cast" is happened in "get" function in "from_base", "p.id= v.get("ID")". SOCI software think it should be type "double" from database, but actually I created table with field "id" as integer, not double. How to solve this problem? I need your help.

My case is below:
struct person
{
int id;
int class;
char name[10];
};

// create table
sql << create table AA (id integer not null, class integer, name varchar2(10), constraint pk_AA primary key (id));

namespace soci
{
// name-based conversion
template<> struct type_conversion
{
typedef values base_type;

static void from_base(values const &v, indicator /* ind */, person &p)
{
  // ignoring possibility that the whole object might be NULL

  p.id= v.get<int>("ID");
  p.class= v.get<int>("CLASS", 0);
  strcpy(p.name, v.get<std::string>("NAME").c_str());
}

static void to_base(person const & p, values & v, indicator & ind)
{
  v.set("ID", p.id);
  v.set("CLASS", p.class);

  std::string str1 = p.name;
  v.set("NAME", str1);
}

};
}

person p1;
sql << "select * from AA where id=:ID", use(2), into(p1);

[zann1x]

With type_conversions, you're using SOCI's dynamic API. This API forces you to use the exact C++ data types that SOCI maps the database types to (see https://soci.sourceforge.net/doc/release/4.0/backends/odbc/#dynamic-binding).

While it is true that you're creating the column id as type integer, you have to keep in mind that you also created a primary key constraint on that column. Some databases treat such columns as something along the lines of numeric(38,0) internally, which of course would get mapped from SQL_NUMERIC to double by SOCI. I don't know how Oracle handles primary keys, but based on your description I would assume that this is exactly the issue here. Retrieving the column as double and then casting it to int might be your only option then.

[330305020]

Thanks for your detailed explaination. It is exactly explained my question. Another column "class" as type integer have the same problem. Oracle treat integer as number(38, 0) as you said.