How to recover after Oracle delete accidentally deletes table data

1、 Recover according to time

In this way, we need to know about the implementation delete The time of the statement .

Query the current system time ：select to_char(sysdate,‘yyyy-mm-dd hh24:mi:ss’) from dual;

Suppose that 2022-04-02 16:27:11 minute , Delete statement executed
delete from demo ;

At this time, the data in the table cannot be queried . We know delete Execution time , Push forward 1 minute （delete Before the execution time , The smaller the better. , In this example 1 Minutes, for example ）, Execute the following statement

select * from DEMO as of timestamp to_timestamp(‘2022-04-02 16:26:11',‘yyyy-mm-dd hh24:mi:ss');

You can see that although the current demo There is no data in the table , But you can find demo Before the table 1 Data in minutes .

recovery 1： At this time, you can use the plsql The export query result function of the tool exports sql file , And then re execute sql In the document insert Statement for data recovery .

recovery 2： Perform the following sql Data recovery ：

flashback table DEMO to timestamp to_timestamp(‘2022-04-02 16:26:11',‘yyyy-mm-dd hh24:mi:ss');

If you make a mistake ORA-08189： Row movement is not enabled , Cannot flash back table

execute ：

alter table DEMO enable row movement;

After adding the table row movement function , It's going on flashback Statement to recover

If you make a mistake : ORA-08194: Flashback table operations are not allowed on materialized views ; Restore by creating a new temporary table as described below .

recovery 3（ Create a new temporary table ）：

newly build demo1 surface , Insert the data to be recovered

create table DEMO1 as select * from DEMO as of timestamp to_timestamp(‘2022-04-02 16:30:11',‘yyyy-mm-dd hh24:mi:ss');

take demo1 The data of the table is restored to demo In the table

insert into DEMO select * from DEMO1 where not exists (select * from DEMO where DEMO.id=DEMO1.id);

recovery 4（ according to scn recovery ）：

Check the current scn Number

select current_scn from v$database;

take scn The number is reduced by a certain number , Execute the following statement , Until we can see delete Up to the data

select * from DEMO as of scn 166937913;

Through the right scn Number , Under execution sql Statement for data recovery

flashback table DEMO to scn 166937913;

summary

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