# ER and attributes for combat

![](./ER_for_combat.png)

### Entity
A Battle has a Battle Number (the primary key) and Date(BattleDate) attribute.

A Combat has a Damage, Weapon and a Result attribute.

### Relationship: Involved (battle)
A combat must have battle involved.

A battle will contain at least on combat.

### Relationship: Involved (Attacker / Defender)
A combat must have at least 1 characters involved.

A Characters may contain empty combat history

# ER and attributes for characters

![](./ER_for_characters.png)

### Entity

A Characters has a Name(key)​, Type, Level, ExperiencePoints, MaxHealth, Health, AttackInScore, DefenceScore, StealthScore, ManaScore, MoneyBank MoneyWallet attribute.


### Relationship: OwnedBy
A character must owned by one player

A player may have many characters

### Relationship: OwnItems
An Items must owned by one character

A character may have many Items

If a character is deleted from the game server, the items will be deleted

### Relationship: Involved

A Combat (either attacker/defender) must owned by one character

A character may involved in many combats

If a character is deleted from the game server, the combat will be deleted


# ER and attributes for customers/players

![](./ER_for_customers.png)


## Entity set

A customers has a AccountNumber(key)​, Name and EMailAddress attribute.

Name is a Multi-valued attribute containing Forename and Surname.

## Relationship Owned By

A Characters must owned by one character

A customers/player may have many character

If a customer/player is deleted from the game server, the characters will be deleted

# ER and attributes for items/inventory

![](./ER_for_items.png)

## Entity set

A Items has a ItemName, ItemType, WeaponType, Quantity, Range, SingleUse, Price, Equipped, BodyPart, Wearable, Worn attribute

A Score is a Multi-valued attribute containing ManaScore, DefendScore and AttackScore.

A ItemKey is an key to indicate the specific item

## Relationship OwnedItems

A Items must owned by one character

A character may have many items

If a character is deleted from the game server, the Items will be deleted


# Overview of ERs

![](./ER_overview.png)