Submitted by: @cincuranet

* Prepare:

CREATE TABLE T_TRANSLATION_META (
F_TRM_ID BIGINT NOT NULL,
F_TRM_CODE VARCHAR(512) CHARACTER SET UTF8 NOT NULL COLLATE
UNICODE_CI
);
CREATE TABLE T_COUNTRY (
F_CNR_ID BIGINT NOT NULL,
F_TRM_NAME_ID BIGINT DEFAULT -1 NOT NULL,
CF_CNR_NAME COMPUTED BY (((select
F_TRM_CODE
from T_TRANSLATION_META
where F_TRM_ID = F_TRM_NAME_ID)))
);

`select rdb$collation_id from rdb$fields where rdb$field_name = 'RDB$5'` returns `null`.

ALTER TABLE T_COUNTRY ALTER CF_CNR_NAME COMPUTED BY (((select
F_TRM_CODE
from T_TRANSLATION_META
where F_TRM_ID = F_TRM_NAME_ID)));

And now the above query return `3`, although the computed column really didn't change.