ForeignKeyChecks

The migration runs with disabled foreign keys, until foreign keys are checked right before changes are committed on disk.

These deferred checks are not executed if the migrator comes from disablingDeferredForeignKeyChecks().

Deferred foreign key checks are necessary for migrations that perform schema changes as described in https://www.sqlite.org/lang_altertable.html#making_other_kinds_of_table_schema_changes

The migration runs for foreign keys on.

Immediate foreign key checks are not compatible with migrations that perform schema changes as described in https://www.sqlite.org/lang_altertable.html#making_other_kinds_of_table_schema_changes