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小編給大家分享一下數據庫中批量插入數據時主鍵沖突怎么辦,希望大家閱讀完這篇文章之后都有所收獲,下面讓我們一起去探討吧!
客戶有這樣一個需求:有一個大表A,有主鍵,經常需要往這個表中批量插入大量數據,但插入的數據可能自身重復或者跟表A重復。
下面測試幾種插入的方法:
DB:ORACLE 11.2.0.4
新建測試表:
新建表scott.tb_01
create table scott.tb_01
as
SELECT level c1,level c2,level c3
FROM DUAL
CONNECT BY LEVEL <= 100000;
在表scott.tb_01上增加主鍵
create unique index scott.pk_tb_01 on scott.tb_01(c1); --這一步不是必需的,因為下一步會自動建索引,但這種建索引再加主鍵的方式可以在建索引的時候加并行。
alter table scott.tb_01 add constraint pk_tb_01 primary key (c1) using index;
新建表scott.tb_02
create table scott.tb_02
as
SELECT level+100000 c1,level c2,level c3
FROM DUAL
CONNECT BY LEVEL <= 100000;
在表scott.tb_02上插入表scott.tb_01的100條數據做為重復數據
insert into scott.tb_02
SELECT c1,c2, c3
FROM scott.tb_01
where rownum <= 100;
commit;
現在需要將表scott.tb_02中和表scott.tb_01非重復的數據插入到scott.tb_01
方法1:關聯插入
INSERT INTO SCOTT.TB_01
SELECT A.* --這里如果表SCOTT.TB_02自身有重復數據,還要加上distinct
FROM SCOTT.TB_02 A
LEFT JOIN SCOTT.TB_01 B
ON A.c1 = B.c2
WHERE B.c1 IS NULL;
100000 rows created.
上面一種常見的插入方法,這個方法的的問題在于,如果表SCOTT.TB_02和表SCOTT.TB_01都很大,兩個表關聯查詢的成本會很高,影響性能。
方法2:使用HINT:IGNORE_ROW_ON_DUPKEY_INDEX
不使用HINT:
INSERT
INTO SCOTT.TB_01
SELECT * FROM SCOTT.TB_02 ;
ERROR at line 1:
ORA-00001: unique constraint (SCOTT.PK_TB_01) violated
從上面可以看出直接將表SCOTT.TB_02插入到表SCOTT.TB_01會出現主鍵沖突,報ORA-00001錯誤。
使用HINT:
INSERT /*+IGNORE_ROW_ON_DUPKEY_INDEX(a PK_tb_01)*/
INTO SCOTT.TB_01 A
SELECT * FROM SCOTT.TB_02 ;
100000 rows created.
從上面可以看出,加上HINT后,表SCOTT.TB_02中和表SCOTT.TB_01沒有主鍵沖突的記錄插入到表SCOTT.TB_01中,沖突的100條記錄沒有插入,也沒有報錯。
方法3:使用impdp的skip_constraint_errors選項
創建dump目錄
create directory dump_home as '/home/oracle';
導出表scott.tb_02
expdp system tables=scott.tb_02 directory=dump_home dumpfile=expdp_tb_02.dmp logfile=expdp_tb_02.log
使用expdp導出表scott.tb_02,用于后續導入到表scott.tb_01中。
導入表scott.tb_02到scott.tb_01,不加skip_constraint_errors選項
impdp system tables=scott.tb_02 remap_table=scott.tb_02:tb_01 content=data_only directory=dump_home dumpfile=expdp_tb_02.dmp logfile=impdp_tb_02.log
Import: Release 11.2.0.4.0 - Production on Tue Dec 5 23:18:49 2017
Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.
Password:
Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
Master table "SYSTEM"."SYS_IMPORT_TABLE_01" successfully loaded/unloaded
Starting "SYSTEM"."SYS_IMPORT_TABLE_01": system/******** tables=scott.tb_02 remap_table=scott.tb_02:tb_01 content=data_only directory=dump_home dumpfile=expdp_tb_02.dmp logfile=impdp_tb_02.log
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
ORA-31693: Table data object "SCOTT"."TB_01" failed to load/unload and is being skipped due to error:
ORA-00001: unique constraint (SCOTT.PK_TB_01) violated
Job "SYSTEM"."SYS_IMPORT_TABLE_01" completed with 1 error(s) at Tue Dec 5 23:19:02 2017 elapsed 0 00:00:09
從上面可以看出,如果不加skip_constraint_errors選項就會報主鍵沖突錯誤,導入失敗。
導入表scott.tb_02到scott.tb_01,加skip_constraint_errors選項
impdp system tables=scott.tb_02 remap_table=scott.tb_02:tb_01 content=data_only directory=dump_home dumpfile=expdp_tb_02.dmp logfile=impdp_tb_02.log data_options=skip_constraint_errors
Import: Release 11.2.0.4.0 - Production on Tue Dec 5 23:21:29 2017
Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.
Password:
Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
Master table "SYSTEM"."SYS_IMPORT_TABLE_01" successfully loaded/unloaded
Starting "SYSTEM"."SYS_IMPORT_TABLE_01": system/******** tables=scott.tb_02 remap_table=scott.tb_02:tb_01 content=data_only directory=dump_home dumpfile=expdp_tb_02.dmp logfile=impdp_tb_02.log data_options=skip_constraint_errors
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
. . imported "SCOTT"."TB_01" 1.796 MB 100000 out of 100100 rows
100 row(s) were rejected with the following error:
ORA-00001: unique constraint (SCOTT.PK_TB_01) violated
Rejected rows with the primary keys are:
Rejected row #1:
column C1: 1
…
Rejected row #99:
column C1: 99
Rejected row #100:
column C1: 100
Job "SYSTEM"."SYS_IMPORT_TABLE_01" successfully completed at Tue Dec 5 23:21:56 2017 elapsed 0 00:00:23
從上面可以看出,導入順利完成,并跳過了主鍵沖突的行,并在impdp的log中顯示行的信息。
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