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\nFLASHBACK TABLE restores the latest version that is available in recycle bin. If you did multiple drop / create you may want to restore oldest versions. Of course it’s documented – everything is in the doc. But an example may be useful to understand it before you need it.
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\nLet’s create and drop several times the DEMO table. I change the column name so that I can check easily which one has been restored
\n20:03:10 SQL> create table DEMO(id number constraint DEMOPK primary key , C1 char );\nTable created.\n20:03:12 SQL> drop table DEMO;\nTable dropped.\n20:03:12 SQL> create table DEMO(id number constraint DEMOPK primary key , C2 char );\nTable created.\n20:03:14 SQL> drop table DEMO;\nTable dropped.\n20:03:14 SQL> create table DEMO(id number constraint DEMOPK primary key , C3 char );\nTable created.\n20:03:16 SQL> drop table DEMO;\nTable dropped.\n20:03:16 SQL> create table DEMO(id number constraint DEMOPK primary key , C4 char );\nTable created.\n20:03:18 SQL> drop table DEMO;\nTable dropped.\n20:03:18 SQL> create table DEMO(id number constraint DEMOPK primary key , C5 char );\nTable created.\n20:03:20 SQL> drop table DEMO;\nTable dropped.\n20:03:20 SQL> create table DEMO(id number constraint DEMOPK primary key , C6 char );\nTable created.\n20:03:22 SQL> drop table DEMO;\nTable dropped.\nHere is what I have in recycle bin
\n\n20:03:22 SQL> select object_name,original_name,type,dropscn,createtime,droptime from user_recyclebin order by dropscn;\n \nOBJECT_NAME ORIGINAL_N TYPE DROPSCN CREATETIME DROPTIME\n------------------------------ ---------- ---------- ---------- ------------------- -------------------\nBIN$KF+J+xYlFjngU3VOqMB9Kw==$0 DEMOPK INDEX 4350801 2016-01-02:20:03:10 2016-01-02:20:03:12\nBIN$KF+J+xYmFjngU3VOqMB9Kw==$0 DEMO TABLE 4350804 2016-01-02:20:03:10 2016-01-02:20:03:12\nBIN$KF+J+xYoFjngU3VOqMB9Kw==$0 DEMOPK INDEX 4350830 2016-01-02:20:03:12 2016-01-02:20:03:14\nBIN$KF+J+xYpFjngU3VOqMB9Kw==$0 DEMO TABLE 4350833 2016-01-02:20:03:12 2016-01-02:20:03:14\nBIN$KF+J+xYrFjngU3VOqMB9Kw==$0 DEMOPK INDEX 4350857 2016-01-02:20:03:14 2016-01-02:20:03:16\nBIN$KF+J+xYsFjngU3VOqMB9Kw==$0 DEMO TABLE 4350861 2016-01-02:20:03:14 2016-01-02:20:03:16\nBIN$KF+J+xYuFjngU3VOqMB9Kw==$0 DEMOPK INDEX 4350885 2016-01-02:20:03:16 2016-01-02:20:03:18\nBIN$KF+J+xYvFjngU3VOqMB9Kw==$0 DEMO TABLE 4350889 2016-01-02:20:03:16 2016-01-02:20:03:18\nBIN$KF+J+xYxFjngU3VOqMB9Kw==$0 DEMOPK INDEX 4350912 2016-01-02:20:03:18 2016-01-02:20:03:20\nBIN$KF+J+xYyFjngU3VOqMB9Kw==$0 DEMO TABLE 4350915 2016-01-02:20:03:18 2016-01-02:20:03:20\nBIN$KF+J+xY0FjngU3VOqMB9Kw==$0 DEMOPK INDEX 4350939 2016-01-02:20:03:20 2016-01-02:20:03:22\nBIN$KF+J+xY1FjngU3VOqMB9Kw==$0 DEMO TABLE 4350943 2016-01-02:20:03:20 2016-01-02:20:03:22\n \n12 rows selected.\nand my goal now is to restore a previous version.
\nSo the documentation tells to issue multiple flashback commands:
\n\n20:03:22 SQL> flashback table DEMO to before drop;\nFlashback complete.\n \n20:03:22 SQL> desc DEMO;\n Name Null? Type\n -------------- -------- --------\n ID NOT NULL NUMBER\n C6 CHAR(1)\nthat’s the latest version. Let’s issue the command again:
\n\n20:03:22 SQL> flashback table DEMO to before drop;\nflashback table DEMO to before drop\n*\nERROR at line 1:\nORA-38312: original name is used by an existing object\nYes of course, I have to drop it before.
\n\n20:03:22 SQL> drop table DEMO;\nTable dropped.\n \n20:03:22 SQL> flashback table DEMO to before drop;\nFlashback complete.\n \n20:03:22 SQL> desc DEMO;\n Name Null? Type\n -------------- -------- --------\n ID NOT NULL NUMBER\n C6 CHAR(1)\nOk, as I dropped it just before, that the latest version that is restored…
\nIf I want to issue multiple flashback table commands, I have to drop purge so that the intermediate restored tables don’t go to recycle bin
\n\n20:03:22 SQL> drop table DEMO purge;\nTable dropped.\n \n20:03:23 SQL> flashback table DEMO to before drop;\nFlashback complete.\n \n20:03:23 SQL> desc DEMO;\n Name Null? Type\n -------------- -------- --------\n ID NOT NULL NUMBER\n C5 CHAR(1)\nthat’s fine: I restored the N-1 version.
\nThe other solution is to restore it to another table, dropping that other table, or changing name each time:
\n\n20:03:23 SQL> flashback table DEMO to before drop rename to DEMO1;\nFlashback complete.\n \n20:03:23 SQL> desc DEMO1;\n Name Null? Type\n -------------- -------- --------\n ID NOT NULL NUMBER\n C4 CHAR(1)\n \n20:03:23 SQL> flashback table DEMO to before drop rename to DEMO2;\nFlashback complete.\n \n20:03:23 SQL> desc DEMO2;\n Name Null? Type\n -------------- -------- --------\n ID NOT NULL NUMBER\n C3 CHAR(1)\nHere I rewind two older versions.
\nBut there is a direct possibility if you know the version you want from the DBA_RECYCLEBIN view.
\n\n20:03:23 SQL> desc \"BIN$KF+J+xYpFjngU3VOqMB9Kw==$0\"\n Name Null? Type\n -------------- -------- --------\n ID NOT NULL NUMBER\n C2 CHAR(1)\nAnd I restore that directly to a new table:
\n\n20:03:23 SQL> flashback table \"BIN$KF+J+xYpFjngU3VOqMB9Kw==$0\" to before drop rename to DEMO3;\nFlashback complete.\nSo that’s probably the fastest way to restore an old version.
\nAll that is possible because each time we flashback to before drop, the restored version is removed from the recycle bin.
\nFrom my example, only one remains here:
\n20:03:24 SQL> select object_name,original_name,type,dropscn,createtime,droptime from user_recyclebin order by dropscn;\n \nOBJECT_NAME ORIGINAL_N TYPE DROPSCN CREATETIME DROPTIME\n------------------------------ ---------- ---------- ---------- ------------------- -------------------\nBIN$KF+J+xYlFjngU3VOqMB9Kw==$0 DEMOPK INDEX 4350801 2016-01-02:20:03:10 2016-01-02:20:03:12\nBIN$KF+J+xYmFjngU3VOqMB9Kw==$0 DEMO TABLE 4350804 2016-01-02:20:03:10 2016-01-02:20:03:12\nso the safest way is probably to flashback to a different table name each time, and clean that only when you’re sure you don’t need them anymore.
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