Initial commit: nick docs

02 - Data Models/Category.md

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+---
+title: Category
+tags: [data-model, mongoose]
+aliases: [Category Model, Taxonomy, ICategory]
+---
+
+# Category
+
+Hierarchical taxonomy node used by [[PurchaseRequest]] and [[RequestTemplate]]. Each row is bilingual (`name` in the local language, `nameEn` in English), supports parent/child via `parentId`, has an icon and a display `order`, and an `isActive` toggle for soft-removal.
+
+> [!note] Source
+> `backend/src/models/Category.ts:15` — schema definition
+> `backend/src/models/Category.ts:60` — model export
+
+## Schema
+
+| Field | Type | Required | Default | Validation | Index | Description |
+| --- | --- | --- | --- | --- | --- | --- |
+| `name` | String | yes | — | trim | yes | Local language name. |
+| `nameEn` | String | yes | — | trim | yes | English name. |
+| `description` | String | no | — | trim | — | Description. |
+| `icon` | String | no | — | trim | — | Icon identifier / URL. |
+| `isActive` | Boolean | no | `true` | — | yes | Active flag. |
+| `parentId` | ObjectId → [[Category]] | no | `null` | — | yes | Parent category (`null` for top level). |
+| `order` | Number | no | `0` | — | — | Display order. |
+| `createdAt` | Date | auto | — | — | — | Mongoose timestamp. |
+| `updatedAt` | Date | auto | — | — | — | Mongoose timestamp. |
+
+## Virtuals
+
+None defined.
+
+## Indexes
+
+Defined at `backend/src/models/Category.ts:55-58`:
+
+- `{ name: 1 }`
+- `{ nameEn: 1 }`
+- `{ isActive: 1 }`
+- `{ parentId: 1 }`
+
+## Pre/Post Hooks
+
+None declared.
+
+## Instance Methods
+
+None defined.
+
+## Static Methods
+
+None defined.
+
+## Relationships
+
+- **References**: [[Category]] (self, via `parentId`).
+- **Referenced by**: [[PurchaseRequest]] (`categoryId`), [[RequestTemplate]] (`categoryId`).
+
+## State Transitions
+
+No status field — only the `isActive` boolean for soft-disable.
+
+```mermaid
+stateDiagram-v2
+    [*] --> active
+    active --> inactive : admin disables
+    inactive --> active : admin re-enables
+```
+
+## Common Queries
+
+```ts
+// Top-level categories
+Category.find({ parentId: null, isActive: true }).sort({ order: 1 });
+
+// Children of a category
+Category.find({ parentId, isActive: true }).sort({ order: 1 });
+
+// Bilingual search
+Category.find({ $or: [{ name: regex }, { nameEn: regex }], isActive: true });
+
+// Full tree (basic, two-level)
+const roots = await Category.find({ parentId: null }).sort({ order: 1 });
+const children = await Category.find({ parentId: { $in: roots.map(r => r._id) } });
+```
+
+Related: [[PurchaseRequest]], [[RequestTemplate]].