> ## Documentation Index > Fetch the complete documentation index at: https://docs.notesglider.in/llms.txt > Use this file to discover all available pages before exploring further. # Atomic UID System # Atomic UID System ## SECTION 11A — ATOMIC UID SYSTEM ### 11A.1 Purpose The current document schema identifies entities primarily through the document-level `doc-id` in metadata, but lacks unique identifiers for atomic sub-entities such as individual news categories, news items, thumbnail images, and reference images. This creates mapping ambiguity, particularly in the following scenarios: * **Re-generation of past documents** after Cloudinary images have been archived/deleted at the end of the academic year — without UIDs, image-to-news-item mapping relies solely on CDN URLs which become invalid post-archival. * **Cross-document referencing** in aggregation documents (compilations, magazines, quarterly collections, etc.) where news items from multiple newsletters must be uniquely identified. * **Audit and traceability** — linking specific content units to their creation context. ### 11A.2 UID Format Specification All UIDs are prefixed with the document date to ensure temporal uniqueness and prevent collisions across academic years. | Entity | UID Format | | --------------- | ----------------------------------------------------------------------------------------------- | | Base UID | `DDMMYYYY-\{uid-string\}` | | News Category | `DDMMYY-Cat-\{category-name\}-\{documentID\}-\{UID\}` | | News Item | `DDMMYY-News-\{news-name[:10]\}-Cat-\{category-name\}-\{documentID\}-\{UID\}` | | Thumbnail Image | `DDMMYY-thumb-Img-News-\{news-name[:10]\}-Cat-\{category-name\}-\{documentID\}-\{UID\}` | | Reference Image | `DDMMYY-ref-\{index\}-Img-News-\{news-name[:10]\}-Cat-\{category-name\}-\{documentID\}-\{UID\}` | Where: * `DDMMYY` = 6-digit date of the document (e.g. `010326` for March 1, 2026) * `DDMMYYYY` = 8-digit date of the document (e.g. `01032026` for March 1, 2026) * `\{uid-string\}` = A unique random string (e.g. UUID v4 short segment or nanoid) * `\{category-name\}` = Sanitised category name (uppercase, spaces replaced with underscores) * `\{news-name[:10]\}` = First 10 characters of the news headline (sanitised, stripped of special characters) * `\{documentID\}` = The document's `doc-id` (e.g. `NL-20260301-0001`) * `\{index\}` = Order index of the reference image within the news item (1, 2, 3...) * `\{UID\}` = The base UID string for uniqueness ### 11A.3 UID Generation Rules 1. **Backend generates all UIDs** — UIDs are never generated client-side. 2. Backend maintains a **UID log table** (`atomic_uid_log`) that stores every generated UID to ensure uniqueness. 3. Before assigning a UID, the backend checks the log table for collisions. If a collision is detected, a new UID is generated. 4. The `DDMMYYYY` prefix provides a first-pass deduplication layer — UIDs from different dates cannot collide even if the random segment is identical. 5. UIDs are **immutable** once assigned — they are never changed, even if the entity is edited. ### 11A.4 Schema Integration UIDs are embedded in the document JSON schema at the entity level: ```json theme={null} { "news-categories": [ { "category-name": "Science & Technology", "atomic_uid": "010326-Cat-SCIENCE_AND_TECHNOLOGY-NL-20260301-0001-a1b2c3d4", "news-items": [ { "headline": "New Discovery in Physics", "atomic_uid": "010326-News-NewDiscove-Cat-SCIENCE_AND_TECHNOLOGY-NL-20260301-0001-e5f6g7h8", "images": { "thumbnail": { "url": "https://res.cloudinary.com/.../thumb.jpg", "atomic_uid": "010326-thumb-Img-News-NewDiscove-Cat-SCIENCE_AND_TECHNOLOGY-NL-20260301-0001-i9j0k1l2" }, "reference-images": [ { "url": "https://res.cloudinary.com/.../ref1.jpg", "atomic_uid": "010326-ref-1-Img-News-NewDiscove-Cat-SCIENCE_AND_TECHNOLOGY-NL-20260301-0001-m3n4o5p6" } ] } } ] } ] } ``` ### 11A.5 Image MIME-Level Metadata When images are uploaded to Cloudinary, the `atomic_uid` is injected into the image's MIME-level metadata (EXIF/IPTC/XMP fields) so that even if the image is downloaded or extracted from the system, its origin can be traced: * **IPTC Caption**: `atomic_uid` value * **XMP Description**: `atomic_uid` value * **Cloudinary metadata tag**: `atomic_uid` value This ensures proper image-to-news-item mapping even when images are served from Google Drive archives (post-Cloudinary deletion) where only the file itself is available. ### 11A.6 UID in HTML Output When generating `.html` versions of documents, each entity's `atomic_uid` is embedded as a `data-uid` attribute on the corresponding HTML element: ```html theme={null}
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