What is the APEX database?

Could you please elaborate on what exactly the APEX database is? Is it a centralized or decentralized system? What kind of information does it store, and what are its primary functions? Is it specifically designed for the cryptocurrency space, or does it have broader applications? Additionally, what are the benefits and drawbacks of using the APEX database, and how does it compare to other similar databases in the market? I'm curious to learn more about its features and how it operates.