错误：‘bOS::SQL::SQLCommand::SQLOperation’既不是类也不是命名空间

/opt/cBPM/criteria-lin/src/Criteria/Criteria.WorkflowEngine/DataBase/DataBaseTemplate.cpp:1341:66: 错误：‘bOS::SQL::SQLCommand::SQLOperation’既不是类也不是命名空间
  this->executeSQLCommands (connection, &vActivities, SQLCommand::SQLOperation::SELECT, NULL, false);

namespace bOS
{
	namespace SQL
	{
		class BOS_API SQLCommand
		{
		public:
			SQLCommand();
			virtual ~SQLCommand();

			enum SQLOperation
			{
				ADD,
				MODIFY,
				ERASE,
				SELECT,
				CREATE,
				DROP
			};

解决办法：

SQLCommand::SQLOperation::SELECT

替换为：

SQLCommand::SELECT

Getting an “enum is not a class or namespace” error - C++ [duplicate]