Terminology
Use these terms to decide where data belongs and which editor workflow to follow. Most item data moves through this relationship:
Database → Category → Definition → Item → Collection → Inventory
For a shorter visual introduction before this complete glossary, read The Data Model at a Glance.
The database, categories, and definitions form the catalog in the editor. Items, collections, and inventories represent what exists during play.
Core data model
| Object | What it represents | Standard example |
|---|---|---|
| Inventory System Database | The project catalog that stores Item Categories, Item Definitions, Currencies, Crafting Categories, and Crafting Recipes. | GameInventoryDatabase |
| Item Category | A reusable structure that organizes related definitions and declares inherited attributes. Category-based systems can target it, and a category can inherit from more than one parent. | All, Consumable, Equippable, Weapon |
| Item Definition | A template for one type of item and its default values. | Health Potion, Iron Sword, Fire Wand |
| Item | A runtime item created from a definition. Mutable Items can hold values that differ from other Items created from the same definition. | One Iron Sword with its own remaining Durability |
| Item Collection | One named group of Item Stacks inside an Inventory, with optional restrictions or a specialized purpose. | Bag, Equipment |
| Inventory | The component that owns one or more Item Collections. | A player, shop, chest, or enemy Inventory |
The Inventory System Manager loads the Inventory System Database when the game starts. It registers the catalog objects and provides the central lookup and Item-creation service used at runtime.
An Item Definition can inherit from a parent definition in the same category. Its Default Item supplies the baseline values used when a runtime Item is created. Items remain data objects; Item Actions and Item Object Behaviours provide the logic that uses them.
Worked example: from catalog to player Inventory
Start with All as the broad parent category. Place Consumable and Equippable beneath it, then place Weapon beneath Equippable.
- Health Potion uses Consumable.
- Iron Sword and Fire Wand use Weapon, so they also inherit from Equippable and All.
- All can declare common Item Definition attributes such as Icon and Description.
- Weapon can declare attributes used by weapon definitions, such as Attack and Buy Price.
- A per-Item attribute such as Durability can differ between two Iron Sword Items when the category is mutable.
At runtime, the Inventory System Manager creates Items from these definitions. Health Potion Items can be stored in the player’s Bag. An Iron Sword Item can move from Bag to Equipment when it is equipped.
Category placement has consequences: definitions inherit the attributes declared by their category and its ancestors, and category-based Item Actions can use the same relationship. Put an attribute on the broadest category where every descendant genuinely needs it; otherwise, keep it on a narrower category.
Attributes and inheritance
An Attribute is named data defined through an Item Category. Choose its collection according to where its value belongs:
| Attribute collection | Choose it when | Example |
|---|---|---|
| Item Category | Every use of the category should share one category-level value. | A visual identity for the Weapon category |
| Item Definition | Each definition needs its own value, shared by Items created from that definition. | Icon, Description, Attack, Buy Price |
| Item | Each runtime Item may need a different value. | Durability on an individual Iron Sword |
Attribute values support three variants:
- Override replaces the inherited value.
- Inherit uses the parent value unchanged.
- Modify calculates a value from the inherited value or another attribute in the same collection.
Use Item Actions or other gameplay logic for behavior that is more complex than an attribute expression.
Inventory actions and world objects
Item Action
An Item Action is something the player or game can do with an Item from an Inventory. A Consume action can apply to Consumable Items such as Health Potion, while an Equip action can apply to Equippable Items such as Iron Sword or Fire Wand.
An Item Action Set groups actions for an Item Category. A Category Item Action Set combines multiple Item Action Sets so an inventory UI can find the actions that match the selected Item’s categories.
Item Object and Item Object Behaviour
An Item Object binds an Item to a GameObject when that Item needs a presence in the scene, such as a pickup or equipped weapon. An Item Object Behaviour adds scene-based behavior to that object, such as swinging an Iron Sword or firing a Fire Wand.
Storage, quantities, and context
An Inventory can separate Items into collections with different purposes. A common player setup uses Bag for carried Items and Equipment for equipped Items.
| Term | Use it for | Example |
|---|---|---|
| Item Stack | An Item and its amount inside an Item Collection. | A stack of 5 Health Potions in Bag |
| Item Amount | An Item and an amount when no collection context is required. | 2 Health Potions as a recipe input |
| Item Info | An Item Amount plus its source Item Stack and/or Item Collection. | Remove 2 Health Potions from a specific Bag stack |
| Item Slot Set | The names and allowed Item Categories for an Item Slot Collection. | Weapon and armor slots in Equipment |
Use Item Info when moving or removing Items and the exact source matters. Use Item Amount for a simple Item-and-quantity value outside a collection.
Inventory UI terms
An Item View displays an Item through one or more Item View Modules. An Item View Slot hosts an Item View and handles UI interactions such as selection, clicking, dragging, and dropping. For example, a Bag grid can use Item View Slots to display Health Potion and Iron Sword Items and respond when the player selects one.
Currency and crafting
A Currency defines a value that can be exchanged. A project can use Gold as the currency that pays an Item Definition’s Buy Price in a shop.
A Crafting Recipe defines inputs and outputs. A simple recipe can consume ingredient Item Amounts and produce one Health Potion. A Crafting Processor performs the recipe’s runtime logic.
Next steps
- Create a new database with the standard categories and definitions.
- Define attributes at the Category, Definition, or Item level.
- Use the Item Category editor and Item Definition editor to build the catalog.
- Configure the player’s Inventory and its Item Collections.
- Add the relevant Item Actions, Item Objects, Currency, or Crafting workflow.