ColumnDefinitionNode cdn = (ColumnDefinitionNode) node;
String columnName = cdn.getColumnName();
columnChanges.add(TableChange.createAdd(columnName));
if (Column.isInternalName(columnName))
{
throw new ProtectedColumnDDLException(columnName);
}
columnDefNodes.add(cdn);
} break;
case NodeTypes.DROP_COLUMN_NODE: {