Direct Database Work

Baseline: main 23.0+. ORM is the first choice (bitrix-orm — prefer query() / ConditionTree, and ORM write APIs including batch / merge / deleteByFilter before dropping to SQL). Direct SQL is needed for:

• Migrations/DDL in install/index.php / updater.php,
• Bulk operations (UPSERT, REPLACE, windows/CTE),
• Reports with GROUP BY/aggregates that are cumbersome to build via ORM,
• Working with multiple connections (analytical replica, Redis).

Connection

use Bitrix\Main\Application;
use Bitrix\Main\DB\Connection;