Oracle 视图 FLASHBACK_TRANSACTION_QUERY 官方解释，作用，如何使用详细说明

Oracle视图FLASHBACK_TRANSACTION_QUERY是一个支持光回滚事务查询的内置视图，使用该视图可以查询最近一段时间内数据库表中发生变化的会话。它允许用户查看某个事务发生的时间，以及当时动作如何影响数据库中的内容。

使用方法：

1. 首先，应该向Oracle提供要查询的表的名称，以及要查询的时间范围（例如一周前发生变化的事务）；

2. 然后，使用SELECT语句来从FLASHBACK_TRANSACTION_QUERY视图中查询需要的数据，如下所示：

SELECT * FROM FLASHBACK_TRANSACTION_QUERY WHERE table_name = ‘name_of_your_table’ AND action_ timestamp >= ‘start_timestamp’ AND action_timestamp

FLASHBACK_TRANSACTION_QUERY displays information about all flashback transaction queries in the database.

The database must have at least minimal supplemental logging enabled to avoid unpredictable behavior.

Column	Datatype	Description
`XID`	`RAW(8)`	Transaction identifier
`START_SCN`	`NUMBER`	Transaction start system change number (SCN)
`START_TIMESTAMP`	`DATE`	Transaction start timestamp
`COMMIT_SCN`	`NUMBER`	Transaction commit system change number; NULL for active transactions
`COMMIT_TIMESTAMP`	`DATE`	Transaction commit timestamp; NULL for active transactions
`LOGON_USER`	`VARCHAR2(128)`	Logon user for the transaction
`UNDO_CHANGE#`	`NUMBER`	Undo system change number (`1` or higher)
`OPERATION`	`VARCHAR2(32)`	Forward-going DML operation performed by the transaction: `D` – Delete `I` – Insert `U` – Update `B` `UNKNOWN`
`TABLE_NAME`	`VARCHAR2(256)`	Name of the table to which the DML applies
`TABLE_OWNER`	`VARCHAR2(386)`	Owner of the table to which the DML applies
`ROW_ID`	`VARCHAR2(19)`	Rowid of the row that was modified by the DML
`UNDO_SQL`	`VARCHAR2(4000)`	SQL to undo the DML indicated by `OPERATION`