AAC Database - Document Model

The application uses PouchDB (a browser-based NoSQL database) for local storage, with CouchDB and Firebase Cloud Firestore synchronization for cloud backup. Data is stored as JSON documents rather than in relational tables.

Core Document Types

GridData

Represents a complete communication grid (board). Each grid contains an array of grid elements arranged in a layout.

GridData {
  id: string                  // unique identifier
  modelName: "GridData"
  modelVersion: string        // schema version
  label: object | string      // grid name (locale map or plain string)
  rowCount: number            // number of rows in grid layout
  minColumnCount: number      // minimum columns in grid layout
  gridElements: GridElement[] // array of elements in the grid
  isGlobal: boolean           // whether this is the global/home grid
}

GridElement

Represents a single tile/cell within a grid. Elements can be normal communication tiles, collect elements, prediction elements, or live data elements.

GridElement {
  id: string
  modelName: "GridElement"
  width: number               // tile width in grid units
  height: number              // tile height in grid units
  x: number                   // grid position x
  y: number                   // grid position y
  label: object | string      // display text (locale map or string)
  type: string                // ELEMENT_TYPE_NORMAL | ELEMENT_TYPE_COLLECT |
                              // ELEMENT_TYPE_PREDICTION | ELEMENT_TYPE_LIVE
  image: GridImage             // optional image for the tile
  actions: object[]           // array of actions triggered on selection
  backgroundColor: string     // tile background color
  borderColor: string         // tile border color
  fontColor: string           // text color
  hidden: boolean             // whether element is hidden
  colorCategory: string       // color coding category
}

MetaData

Stores user-level settings and configuration.

MetaData {
  id: string
  modelName: "MetaData"
  inputConfig: object         // input method configuration
  colorConfig: object         // color scheme settings
  textConfig: object          // text display settings
  notificationConfig: object  // notification preferences
  locked: boolean             // whether UI is locked
}

GridImage

Image data associated with a grid element.

GridImage {
  id: string
  data: string                // base64-encoded image data or URL
  author: string              // image attribution
  authorURL: string           // author link
}

EncryptedObject

Wrapper for encrypted data stored in Cloud Firestore.

EncryptedObject {
  id: string
  modelName: "EncryptedObject"
  encryptedDataBase64: string  // AES-encrypted JSON payload
  modelVersionShort: string    // short version for metadata
}

Document Relationships

Storage Architecture

• Local: PouchDB stores documents in IndexedDB within the browser
• Remote (optional): Firebase Cloud Firestore instance for cross-device synchronization, caregiver/student profile metadata, and board assignments.
• Encryption: All remote data is AES-encrypted using SJCL before sync
• Authentication: Firebase Authentication (Google OAuth SSO) handles user registration and login.
• Prediction Model: Stored separately in localStorage as JSON (~50KB)