Imagine you are a compliance manager at an investment firm operating in the EU. MiFID II has stringent requirements for Transaction Reporting and Reference Data Reporting. Please elaborate on the main objectives and key requirements of Transaction Reporting and Reference Data Reporting under MiFID II, and the challenges your firm might face in implementing and maintaining compliance with these reporting obligations, along with corresponding mitigation strategies. Specifically, discuss the role of the compliance department in this process.

设想你是一家在欧盟运营的投资公司的合规经理。MiFID II 对交易报告（Transaction Reporting）和参考数据报告（Reference Data Reporting）提出了严格要求。请你详细阐述 MiFID II 下交易报告和参考数据报告的主要目的、关键要求，以及你的公司在实施和维持这些报告合规性方面可能面临的挑战和相应的应对策略。特别说明合规部门在此过程中扮演的角色。