ConnectAndRead

VTKExamples/Cxx/Databases/SQL/MySQL/ConnectAndRead

Code

ConnectAndRead.cxx

#include <vtkSmartPointer.h>
#include <vtkMySQLDatabase.h>
#include <vtkSQLQuery.h>
#include <vtkVariant.h>

/*
If you get the error:
Unsupported protocol: mysql
It means you must recompile VTK with VTK_USE_MYSQL = ON

If you get the error:
vtkMySQLDatabase::New() is not defined
It means that cmake did not find your mysql include and library
path correctly (ie.  MYSQL_INCLUDE_DIRECTORIES, etc)
*/

int main(int, char *[])
{
  // url syntax:
  // mysql://'[[username[':'password]'@']hostname[':'port]]'/'[dbname]

  vtkSmartPointer<vtkMySQLDatabase> db =
    vtkSmartPointer<vtkMySQLDatabase>::Take(vtkMySQLDatabase::SafeDownCast(
            vtkSQLDatabase::CreateFromURL( "mysql://root@localhost/TestDatabase" ) ));

  bool status = db->Open();

  std::cout << "Database open? " << status << std::endl;

  if(!status)
  {
    return EXIT_FAILURE;
  }

  vtkSmartPointer<vtkSQLQuery> query =
    vtkSmartPointer<vtkSQLQuery>::Take(db->GetQueryInstance());

  std::string createQuery( "SELECT PointId FROM TestTable");
  std::cout << createQuery << std::endl;
  query->SetQuery( createQuery.c_str() );
  query->Execute();

  for ( int col = 0; col < query->GetNumberOfFields(); ++ col )
  {
    if ( col > 0 )
    {
      cerr << ", ";
    }
    cerr << query->GetFieldName( col );
  }
  cerr << endl;
  while ( query->NextRow() )
  {
    for ( int field = 0; field < query->GetNumberOfFields(); ++ field )
    {
      if ( field > 0 )
      {
        cerr << ", ";
      }
      cerr << query->DataValue( field ).ToString().c_str();
    }
    cerr << endl;
  }

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(ConnectAndRead)

find_package(VTK COMPONENTS 
  vtkCommonCore
  vtkIOMySQL
  vtkIOSQL QUIET)
if (NOT VTK_FOUND)
  message("Skipping ConnectAndRead: ${VTK_NOT_FOUND_MESSAGE}")
  return ()
endif()
message (STATUS "VTK_VERSION: ${VTK_VERSION}")
if (VTK_VERSION VERSION_LESS "8.90.0")
  # old system
  include(${VTK_USE_FILE})
  add_executable(ConnectAndRead MACOSX_BUNDLE ConnectAndRead.cxx )
  target_link_libraries(ConnectAndRead PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(ConnectAndRead MACOSX_BUNDLE ConnectAndRead.cxx )
  target_link_libraries(ConnectAndRead PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS ConnectAndRead
    MODULES ${VTK_LIBRARIES}
    )
endif () 

Download and Build ConnectAndRead

Click here to download ConnectAndRead and its CMakeLists.txt file. Once the tarball ConnectAndRead.tar has been downloaded and extracted,

cd ConnectAndRead/build 

If VTK is installed:

cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

make

and run it:

./ConnectAndRead

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.