当值> = 16时ResultSet-> getString（）崩溃

Question

ResultSet *search;
....
....
search= prepareStatement->executeQuery();


while (search->next())
{
cout << "Email Found: " << search->getString("EmailColumn") << endl; //crashes here
}

From the code above, calling getString() function actually gets the value from the database. But then it crashes the program. It displays the value then crashes the program.

I discovered the problem but couldn't fix it. I can't tell if this is a bug or something else .

The problem only happens when the length of the value in the EmailColumn column is more or equals to 16 . No error if the length of the value is less or equals to 15 .

Any solution or workarounds for this?

Answer 1

I solved it. The solution is to build your own C++ Connector and use the dll files it compiles. The dll distributed by Oracle was made with a different version of Visual Studio compiler that I am currently using. The first answer here will show you how to build it yourself. MySQL Connector C++ 64bit build from source in Visual Studio 2012 ?

Answer 2

I had almost the same problem (and realized too late that Oracle is not supporting the library for Windows anymore). The following workaround worked for me:

ResultSet *search;
....
....
search= prepareStatement->executeQuery();

while( search->next() )
{
  string const * theString = 
    new string( search->getString( "EmailColumn") );

  cout << *theString << endl;

  operator delete( theString );
  theString = nullptr;
}

My guess is that by this construction VisualStudio 2015 is compiling code that is not calling the destructor std::string::~string() (which caused the crash for my application) for a string that is created by the library via ResultsSet::getString().