Deleting the sensitive columns from the old table and preserving the data from those columns for audit purposes or to ensure the ability to do an undo.

从旧表中删除敏感列，并保留那些列中的数据，以便用于审计或者确保可以执行撤销。

youdao

Among those sitting quietly across the table was his old deputy, Wang Zhihua, who was now a county oil official.

ECONOMIST: In rural China, a private oil boom became a state-owned one