int main()
{
    try
    {
        // regular code
    }
    catch (std::exception const & e)
    {
        cerr << "Bang! " << e.what() << endl;
    }
}

Portability note:

The Oracle backend can also throw the instances of the oracle_soci_error, which is publicly derived from soci_error and has an additional public err_num_ member containing the Oracle error code:

int main()
{
    try
    {
        // regular code
    }
    catch (soci::oracle_soci_error const & e)
    {
        cerr << "Oracle error: " << e.err_num_
            << " " << e.what() << endl;
    }
    catch (soci::exception const & e)
    {
        cerr << "Some other error: " << e.what() << endl;
    }
}

Portability note:

The MySQL backend can throw instances of the mysql_soci_error, which is publicly derived from soci_error and has an additional public err_num_ member containing the MySQL error code (as returned by mysql_errno()):

int main()
{
    try
    {
        // regular code
    }
    catch (soci::mysql_soci_error const & e)
    {
        cerr << "MySQL error: " << e.err_num_
            << " " << e.what() << endl;
    }
    catch (soci::exception const & e)
    {
        cerr << "Some other error: " << e.what() << endl;
    }
}

Portability note:

The PostgreSQL backend can also throw the instances of the postgresql_soci_error, which is publicly derived from soci_error and has an additional public sqlstate() member function returning the five-character "SQLSTATE" error code:

int main()
{
    try
    {
        // regular code
    }
    catch (soci::postgresql_soci_error const & e)
    {
        cerr << "PostgreSQL error: " << e.sqlstate()
            << " " << e.what() << endl;
    }
    catch (soci::exception const & e)
    {
        cerr << "Some other error: " << e.what() << endl;
    }
}