= Legends of the Balkans - Database Documentation =

== Entity Relationship Diagram ==
[[Image(lotb_erdiagram.png)]]

== Data Requirements ==

=== Entities ===
Below are the core entities in the database, their descriptions, and attributes:

- **Player**: Represents a game user with login credentials.
  - `PlayerID` (Primary Key)
  - `Username`
  - `Password`
  - `Email`

- **Character**: A player-controlled entity in the game.
  - `CharacterID` (Primary Key)
  - `PlayerID` (Foreign Key → Player)
  - `Name`
  - `Health`
  - `EXP`
  - `Gold`

- **Faction**: Represents a faction that characters can join.
  - `FactionID` (Primary Key)
  - `Name`
  - `Description`

- **Reputation**: Tracks character reputation with different factions.
  - `CharacterID` (Foreign Key → Character)
  - `FactionID` (Foreign Key → Faction)
  - `ReputationPoints`
  - `Rank`

- **Quest**: Missions that characters can complete.
  - `QuestID` (Primary Key)
  - `Name`
  - `EXP_Required`
  - `EXP_Reward`
  - `Gold_Reward`

- **Item**: Objects that characters can own, craft, or trade.
  - `ItemID` (Primary Key)
  - `Name`
  - `Type`
  - `Rarity`
  - `Craftable`

- **Enemy**: Represents hostile NPCs in the game.
  - `EnemyID` (Primary Key)
  - `Name`
  - `Health`
  - `Damage`
  - `LootDrop`

- **Trader**: NPC merchants selling items.
  - `TraderID` (Primary Key)
  - `Name`
  - `Type`

- **Market**: A system where players can list and sell items.
  - `MarketID` (Primary Key)
  - `ItemID` (Foreign Key → Item)
  - `SellerID` (Foreign Key → Player)
  - `Price`

- **Guild**: Player-created groups for collaboration.
  - `GuildID` (Primary Key)
  - `Name`
  - `LeaderID` (Foreign Key → Player)

== Relations ==

=== 1-1 Relations ===
- `Guild.LeaderID` → `Player.PlayerID`: A guild has a single leader, who is a player.

=== 1-N Relations ===
- `Character.PlayerID` → `Player.PlayerID`: A player can have multiple characters.
- `Character.FactionID` → `Faction.FactionID`: A character belongs to one faction.
- `Market.SellerID` → `Player.PlayerID`: A player can list multiple items on the market.

=== N-N Relations ===
- `ReputationIn(CharacterID, FactionID, ReputationPoints, Rank)`: A character can have reputation with multiple factions, and factions can have multiple characters. This relation tracks the `ReputationPoints` and `Rank` for each character faction pair.
- `Completes(CharacterID, QuestID)`: A character can accept multiple quests, and quests can be taken by multiple characters.
- `Owns(CharacterID, ItemID, Quantity)`: A character can own multiple items, and items can belong to multiple characters.
- `Drops(EnemyID, ItemID, Quantity)`: Enemies can drop multiple items, and items can be dropped by multiple enemies.
- `Sells(TraderID, ItemID, Quantity)`: Traders can sell multiple items, and items can be sold by multiple traders.
- `IsMember(CharacterID, GuildID, Role)`: A character can join a guild, and a guild can have multiple members. The `Role` attribute defines if the character is a "Leader" or "Member" in the guild.