Method GetIndexSpecification

IO/SQL/vtkSQLDatabase.cxx:233–299

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//------------------------------------------------------------------------------
vtkStdString vtkSQLDatabase::GetIndexSpecification(
  vtkSQLDatabaseSchema* schema, int tblHandle, int idxHandle, bool& skipped)
{
  vtkStdString queryStr;

  int idxType = schema->GetIndexTypeFromHandle(tblHandle, idxHandle);
  switch (idxType)
  {
    case vtkSQLDatabaseSchema::PRIMARY_KEY:
      queryStr = ", PRIMARY KEY ";
      skipped = false;
      break;
    case vtkSQLDatabaseSchema::UNIQUE:
      queryStr = ", UNIQUE ";
      skipped = false;
      break;
    case vtkSQLDatabaseSchema::INDEX:
      // Not supported within a CREATE TABLE statement by all SQL backends:
      // must be created later with a CREATE INDEX statement
      queryStr = "CREATE INDEX ";
      skipped = true;
      break;
    default:
      return {};
  }

  // No index_name for PRIMARY KEYs nor UNIQUEs
  if (skipped)
  {
    queryStr += schema->GetIndexNameFromHandle(tblHandle, idxHandle);
  }

  // CREATE INDEX <index name> ON <table name> syntax
  if (skipped)
  {
    queryStr += " ON ";
    queryStr += schema->GetTableNameFromHandle(tblHandle);
  }

  queryStr += " (";

  // Loop over all column names of the index
  int numCnm = schema->GetNumberOfColumnNamesInIndex(tblHandle, idxHandle);
  if (numCnm < 0)
  {
    vtkGenericWarningMacro(
      "Unable to get index specification: index has incorrect number of columns " << numCnm);
    return {};
  }

  bool firstCnm = true;
  for (int cnmHandle = 0; cnmHandle < numCnm; ++cnmHandle)
  {
    if (firstCnm)
    {
      firstCnm = false;
    }
    else