Does REMOVE FIELD delete the data in SurrealDB?

REMOVE FIELD on an existing table

Warning: the statement succeeds, then writes fail, access changes, or the table is held up.

What happens

Observed on SurrealDB 3.0.2: after REMOVE FIELD legacy ON user on a SCHEMAFULL table, SELECT still returns legacy = 1, and UPDATE user:1 SET email = 'b' fails with "Found field 'legacy', but no such field exists". Unsetting the field first, then removing it, leaves the record writable.

Why it is dangerous on a populated table

SurrealDB checks a schema change against new writes, not the records already stored, so an empty table hides it: on a populated one every old record is a write waiting to fail, and whole-table work runs for the length of the table in one transaction.

Fires on

REMOVE FIELD legacy_flag ON TABLE user;

The safe pattern

UPDATE user UNSET legacy_flag WHERE legacy_flag IS NOT NONE;
REMOVE FIELD legacy_flag ON TABLE user;

Fixtures

The rule ships with these files and the test suite runs them on every change: the first set must fire, the second must stay silent.

REMOVE FIELD legacy_flag ON TABLE user;

REMOVE FIELD IF EXISTS legacy_flag ON user;

DEFINE TABLE scratch SCHEMAFULL;
DEFINE FIELD note ON TABLE scratch TYPE string;
REMOVE FIELD note ON TABLE scratch;

UPDATE user UNSET legacy_flag WHERE legacy_flag IS NOT NONE;
REMOVE FIELD legacy_flag ON TABLE user;

How to check locally

npx bolvrk check migration.surql --engine=surrealdb