UPDATE and DELETE

UPDATE and DELETE operate on keyed current state. Append tables are immutable through these statements.

Update

UPDATE balances
SET balance = balance + 25,
    updated_at = cast('2026-07-09 14:30:00.000000', 'DateTime64(6)')
WHERE address = 'alice' AND asset = 'USD';

Every assignment expression reads the row as it existed before that update. Assignments in the same statement do not observe one another's newly computed values.

A predicate may match more than one key:

UPDATE balances
SET balance = 0
WHERE asset = 'TEST';

Delete

DELETE FROM balances
WHERE address = 'alice' AND asset = 'USD';

Deletion removes the current keyed row. It participates in the same statement visibility and durability machinery as other committed mutations.

Restrictions

• The target must be a keyed table.
• Subqueries are not supported in UPDATE assignments, UPDATE ... WHERE, or DELETE ... WHERE.
• Schema and type checks occur before the mutation is published.
• There is no RETURNING contract in the current surface.
• There is no multi-statement transaction around a sequence of mutations.

For append-only correction workflows, write a new event and resolve current state in a keyed projection or query rather than attempting in-place mutation.