diff --git a/database/schema/schema.sql b/database/schema/schema.sql
index da93ed9..332b363 100644
--- a/database/schema/schema.sql
+++ b/database/schema/schema.sql
@@ -596,4 +596,123 @@ BEGIN
     'merge_timestamp', NOW()
   );
 END;
-$$ LANGUAGE plpgsql;
\ No newline at end of file
+$$ LANGUAGE plpgsql;
+
+-- ============================================
+-- KOREADER SYNC FUNCTIONS (Phase 3)
+-- ============================================
+
+-- Bulk update progress from KOReader sync data
+CREATE OR REPLACE FUNCTION bulk_update_progress_from_koreader(
+  p_user_id UUID,
+  p_sync_data JSONB
+) RETURNS TABLE (
+  media_item_id UUID,
+  success BOOLEAN,
+  message TEXT
+) AS $$
+DECLARE
+  book_record JSONB;
+  media_uuid UUID;
+  existing_progress reading_progress%ROWTYPE;
+  conflict_detected BOOLEAN;
+BEGIN
+  FOR book_record IN SELECT * FROM jsonb_array_elements(p_sync_data->'books')
+  LOOP
+    -- Try to find media item by UUID
+    media_uuid := NULL;
+    SELECT id INTO media_uuid FROM media_items WHERE id = (book_record->>'uuid')::uuid;
+
+    -- If not found by UUID, try to match by file path
+    IF media_uuid IS NULL AND book_record ? 'file_path' THEN
+      SELECT id INTO media_uuid FROM media_items WHERE file_path = book_record->>'file_path';
+    END IF;
+
+    -- If still not found, try to match by title + author
+    IF media_uuid IS NULL THEN
+      SELECT id INTO media_uuid FROM media_items 
+      WHERE title = book_record->>'title' 
+        AND author = book_record->>'author'
+      LIMIT 1;
+    END IF;
+
+    -- If no match found, return failure
+    IF media_uuid IS NULL THEN
+      RETURN QUERY SELECT NULL::uuid, FALSE, 'media item not found';
+      CONTINUE;
+    END IF;
+
+    -- Check for conflicts
+    conflict_detected := detect_conflict(media_uuid, book_record, 'koreader');
+
+    -- Check if progress exists
+    SELECT * INTO existing_progress FROM reading_progress 
+    WHERE media_item_id = media_uuid AND user_id = p_user_id;
+
+    -- Update or insert progress
+    IF existing_progress.media_item_id IS NOT NULL THEN
+      UPDATE reading_progress SET
+        percentage = (book_record->>'percentage')::FLOAT,
+        character_offset = CASE WHEN book_record ? 'character' THEN (book_record->>'character')::BIGINT ELSE existing_progress.character_offset END,
+        epubcfi = CASE WHEN book_record ? 'epubcfi' THEN (book_record->>'epubcfi')::TEXT ELSE existing_progress.epubcfi END,
+        chapter = CASE WHEN book_record ? 'chapter' THEN (book_record->>'chapter')::INTEGER ELSE existing_progress.chapter END,
+        chapter_progress = (book_record->>'percentage')::FLOAT,
+        last_sync_device = 'koreader',
+        last_sync_source = 'koreader',
+        last_sync_timestamp = NOW(),
+        conflict_detected = conflict_detected,
+        conflict_resolved = NOT conflict_detected,
+        last_read_at = CASE WHEN book_record ? 'last_read' THEN (book_record->>'last_read')::TIMESTAMP WITH TIME ZONE ELSE NOW() END,
+        current_page = CASE WHEN book_record ? 'page' THEN (book_record->>'page')::INTEGER ELSE existing_progress.current_page END,
+        total_pages = CASE WHEN book_record ? 'total_pages' THEN (book_record->>'total_pages')::INTEGER ELSE existing_progress.total_pages END
+      WHERE media_item_id = media_uuid AND user_id = p_user_id;
+    ELSE
+      INSERT INTO reading_progress (
+        media_item_id,
+        user_id,
+        percentage,
+        character_offset,
+        epubcfi,
+        chapter,
+        chapter_progress,
+        last_sync_device,
+        last_sync_source,
+        last_sync_timestamp,
+        conflict_detected,
+        conflict_resolved,
+        last_read_at,
+        current_page,
+        total_pages
+      ) VALUES (
+        media_uuid,
+        p_user_id,
+        (book_record->>'percentage')::FLOAT,
+        CASE WHEN book_record ? 'character' THEN (book_record->>'character')::BIGINT ELSE NULL END,
+        CASE WHEN book_record ? 'epubcfi' THEN (book_record->>'epubcfi')::TEXT ELSE NULL END,
+        CASE WHEN book_record ? 'chapter' THEN (book_record->>'chapter')::INTEGER ELSE NULL END,
+        (book_record->>'percentage')::FLOAT,
+        'koreader',
+        'koreader',
+        NOW(),
+        conflict_detected,
+        NOT conflict_detected,
+        CASE WHEN book_record ? 'last_read' THEN (book_record->>'last_read')::TIMESTAMP WITH TIME ZONE ELSE NOW() END,
+        CASE WHEN book_record ? 'page' THEN (book_record->>'page')::INTEGER ELSE NULL END,
+        CASE WHEN book_record ? 'total_pages' THEN (book_record->>'total_pages')::INTEGER ELSE NULL END
+      );
+    END IF;
+
+    -- Create conflict record if detected
+    IF conflict_detected THEN
+      INSERT INTO sync_conflicts (media_item_id, user_id, conflict_type, conflict_data)
+      VALUES (media_uuid, p_user_id, 'progress', jsonb_build_object(
+        'koreader', book_record,
+        'timestamp', NOW()
+      ));
+    END IF;
+
+    RETURN QUERY SELECT media_uuid, TRUE, 
+      CASE WHEN conflict_detected THEN 'conflict detected' ELSE 'success' END;
+  END LOOP;
+END;
+$$ LANGUAGE plpgsql;