A marine research institute uses a database to track its deep-sea exploration vessels and their respective scientific dives. The tables below show a sample of the data stored in this database.
| VesselID | VesselName | MaxDepth | Country |
|---|---|---|---|
| V801 | Nautilus IV | 4500 | France |
| V802 | DeepReach | 6000 | USA |
| V803 | Shinkai 2 | 6500 | Japan |
| DiveID | VesselID | Location | DiveYear |
|---|---|---|---|
| D911 | V801 | Mariana Trench | 2018 |
| D912 | V801 | Tonga Trench | 2019 |
| D913 | V802 | Puerto Rico | 2021 |
| D914 | V803 | Kermadec Trench | 2022 |
Define the term relational database.