關於 oracle 外來鍵引用 與 goldengate

shilei1發表於2014-05-17
一、準備知識
約束放置在表中,有以下五種約束:
 NOT NULL          非空約束C     指定的列不允許為空值
 UNIQUE             唯一約束U     指定的列中沒有重複值,或該表中每一個值或者每一組值都將是唯一的
 PRIMARY KEY       主鍵約束P     唯一的標識出表的每一行,且不允許空值值,一個表只能有一個主鍵約束
 FOREIGN KEY       外來鍵約束R     一個表中的列引用了其它表中的列,使得存在依賴關係,可以指向引用自身的列
 CHECK              條件約束C     指定該列是否滿足某個條件
約束命名規則
 如果不指定約束名Oracle server 自動按照SYS_Cn 的格式指定約束名,也可手動指定,
 推薦的約束命名是:約束型別_表名_列名。
 NN:NOT NULL          非空約束,比如nn_emp_sal
 UK:UNIQUE KEY         唯一約束
 PK:PRIMARY KEY       主鍵約束
 FK:FOREIGN KEY       外來鍵約束
 CK:CHECK             條件約束
外來鍵約束是用來維護從表和主表的引用完整性的,所以外來鍵約束要涉及兩個表。
 FOREIGN KEY: 在表級指定子表中的列
 REFERENCES: 標示在父表中的列
 ON DELETE CASCADE: 當父表中的列被刪除時,子表中相對應的列也被刪除
 ON DELETE SET NULL: 子表中相應的列置空
 
二、外來鍵建立測試
foreign_main為主表
foreign_sub為從表
object_id做為foreign_sub的外來鍵,參考主表foreign_main的object_id值
 
SQL> create table foreign_main as select object_id from all_objects;
Table created.
SQL> select count(*) from foreign_main;
  COUNT(*)
----------
     49571
SQL> create table foreign_sub as select object_id,object_name from all_objects;
Table created.
 
建議使用主表的主鍵做外來鍵,即使不是主表的主鍵也應該是唯一約束的欄位做為外來鍵
 
SQL> alter table foreign_main add constraint pk_fsid primary key(object_id);
Table altered.
 
SQL> delete from foreign_sub where object_name = 'FOREIGN_MAIN';
1 row deleted.
 
SQL> commit;
Commit complete.
 
SQL>  alter table foreign_sub add constraint fr_fssid foreign key(object_id) references foreign_main(object_id);
Table altered.
 
從表插入一條主表object_id中不存在的記錄測試
SQL> insert into foreign_sub values(1,'ts');
insert into foreign_sub values(1,'ts')
*
ERROR at line 1:
ORA-02291: integrity constraint (TEST.FR_FSSID) violated - parent key not found
提示主表資料不存在,從表不能建立主表不存在的object_id以保證完整性
 
三、級聯刪除測試
 
SQL>  alter table foreign_sub drop constraint fk_fs_oid;
Table altered.
SQL>  alter table foreign_sub add constraint fk_fs_oid foreign key(object_id) references foreign_main(object_id) on delete cascade;
Table altered.
 
cascade下仍然不能單獨更新主表外來鍵欄位
 
SQL> update foreign_main set object_id=52012 where object_id=52010;
update foreign_main set object_id=52012 where object_id=52010
*
ERROR at line 1:
ORA-02292: integrity constraint (TEST.FK_FS_OID) violated - child record found
 
cascade模式下可以透過主表刪除外來鍵欄位資料關聯刪除從表資料
 
SQL> select * from foreign_sub where object_id=52010;
 OBJECT_ID OBJECT_NAME
---------- ------------------------------
     52010 IDX_BJNAME
 
SQL> delete from foreign_main where object_id=52010;
1 row deleted.
 
SQL> commit;
Commit complete.
 
SQL> select * from foreign_sub where object_id=52010;
no rows selected
 
外來鍵相關常用操作及參考文件
 
建立外來鍵
alter table 表名 add constraint 外來鍵名 foreign key(從表外來鍵欄位) references foreign_main(主表外來鍵欄位);
drop表外來鍵
alter table 表名 drop constraint 外來鍵名;
透過外來鍵找表
select * from user_constraints where constraint_type='R' and constraint_name=upper('外來鍵名');
透過表找外來鍵
select * from user_constraints where constraint_type='R' and table_name=upper('表名');
查詢表的外來鍵(包括名稱,引用表的表名和對應的鍵名,下面是分成多步查詢):
select * from user_constraints c where c.constraint_type = 'R' and c.table_name = 要查詢的表
查詢引用表的鍵的列名:
select * from user_cons_columns cl where cl.constraint_name = 外來鍵引用表的鍵名
 
外來鍵約束臨時disabled
alter table 表名 disable constraint 外來鍵名;
 
在SQL92標準中定義了幾種外來鍵改變後,如何處理子表記錄的動作,其中包括:
 
限制Restrict:這種方式不允許對被參考的記錄的鍵值執行更新或刪除的操作;置為空Set to null:當參考的資料被更新或者刪除,那麼所有參考它的外來鍵值被置為空;
置為預設值Set to default:當參考的資料被更新或者刪除,那麼所有參考它的外來鍵值被置為一個預設值;
級聯Cascade:當參考的資料被更新,則參考它的值同樣被更新,當參考的資料被刪除,則參考它的子表記錄也被刪除;
不做操作No action:這種方式不允許更新或刪除被參考的資料。和限制方式的區別在於,這種方式的檢查發生在語句執行之後。Oracle預設才會的方式就是這種方式。
 
Col OWNER FOR A6
COL R_OWNER FOR A6
COL TABLE_NAME FOR A15
select OWNER, TABLE_NAME, CONSTRAINT_NAME, CONSTRAINT_TYPE, R_OWNER, R_CONSTRAINT_NAME, DELETE_RULE from user_constraints where table_name in ('FOREIGN_MAIN', 'FOREIGN_SUB');
 
Select CONSTRAINT_NAME from user_constraints e where e.table_name='IMS_COLUMN' and owner='WSJD_ELMS6';
Select b.table_name,b.column_name, A.CONSTRAINT_TYPE, C.TABLE_NAME from user_constraints a, user_cons_columns b, user_constraints C 
WHERE a.constraint_name = b.constraint_name AND 
A.R_CONSTRAINT_NAME = C.CONSTRAINT_NAME
AND a.r_constraint_name IN (Select CONSTRAINT_NAME from user_constraints e where e.table_name='FOREIGN_MAIN' and owner='SCOTT');
create table foreign_sub as select  object_id, object_name from user_objects;
 
create table foreign_main as select object_id from foreign_sub;
 
alter table foreign_main add constraint pk_foreign_main_object_id primary key(object_id); 
 
alter table foreign_sub add constraint fr_foreign_sub_object_id foreign key(object_id) references foreign_main(object_id) on delete cascade;
 
alter table foreign_sub drop constraint fr_foreign_sub_object_id;
 
alter table foreign_sub disable constraint fr_foreign_sub_object_id;
 
如在goldengate 沒有禁用外來鍵約束會出現以現錯誤
=============================================
2013-12-26 04:51:25  INFO    OGG-00996  Oracle GoldenGate Delivery for Oracle, rep_app.prm:  REPLICAT REP_APP started.
2013-12-26 04:51:25  WARNING OGG-00869  Oracle GoldenGate Delivery for Oracle, rep_app.prm:  OCI Error ORA-02292: integrity constraint (SCOTT.FR_FOREIGN_SUB_OBJECT_ID) violated - child record found (status = 2292). DELETE FROM "SCOTT"."FOREIGN_MAIN"  WHERE "OBJECT_ID" = :b0.
2013-12-26 04:51:25  WARNING OGG-01004  Oracle GoldenGate Delivery for Oracle, rep_app.prm:  Aborted grouped transaction on 'SCOTT.FOREIGN_MAIN', Database error 2292 (OCI Error ORA-02292: integrity constraint (SCOTT.FR_FOREIGN_SUB_OBJECT_ID) violated - child record found (status = 2292). DELETE FROM "SCOTT"."FOREIGN_MAIN"  WHERE "OBJECT_ID" = :b0).
2013-12-26 04:51:25  WARNING OGG-01003  Oracle GoldenGate Delivery for Oracle, rep_app.prm:  Repositioning to rba 17426 in seqno 29.
2013-12-26 04:51:25  WARNING OGG-01154  Oracle GoldenGate Delivery for Oracle, rep_app.prm:  SQL error 2292 mapping SCOTT.FOREIGN_MAIN to SCOTT.FOREIGN_MAIN OCI Error ORA-02292: integrity constraint (SCOTT.FR_FOREIGN_SUB_OBJECT_ID) violated - child record found (status = 2292). DELETE FROM "SCOTT"."FOREIGN_MAIN"  WHERE "OBJECT_ID" = :b0.
2013-12-26 04:51:25  WARNING OGG-01003  Oracle GoldenGate Delivery for Oracle, rep_app.prm:  Repositioning to rba 17426 in seqno 29.
2013-12-26 04:51:25  ERROR   OGG-01296  Oracle GoldenGate Delivery for Oracle, rep_app.prm:  Error mapping from SCOTT.FOREIGN_MAIN to SCOTT.FOREIGN_MAIN.
2013-12-26 04:51:25  WARNING OGG-01525  Oracle GoldenGate Delivery for Oracle, rep_app.prm:  Failed to open trace output file, 'gglog-REP_APP.dmp', error 13 (Permission denied).
2013-12-26 04:51:25  ERROR   OGG-01668  Oracle GoldenGate Delivery for Oracle, rep_app.prm:  PROCESS ABENDING.
 
2013-12-26 04:52:20  INFO    OGG-00996  Oracle GoldenGate Delivery for Oracle, rep_app.prm:  REPLICAT REP_APP started.
2013-12-26 04:52:20  WARNING OGG-00869  Oracle GoldenGate Delivery for Oracle, rep_app.prm:  No unique key is defined for table 'FOREIGN_SUB'. All viable columns will be used to represent the key, but may not guarantee uniqueness.  KEYCOLS may be used to define the key.
2013-12-26 04:52:20  WARNING OGG-01004  Oracle GoldenGate Delivery for Oracle, rep_app.prm:  Aborted grouped transaction on 'SCOTT.FOREIGN_SUB', Database error 1403 (OCI Error ORA-01403: no data found, SQL ).
2013-12-26 04:52:20  WARNING OGG-01003  Oracle GoldenGate Delivery for Oracle, rep_app.prm:  Repositioning to rba 17426 in seqno 29.
2013-12-26 04:52:20  WARNING OGG-01154  Oracle GoldenGate Delivery for Oracle, rep_app.prm:  SQL error 1403 mapping SCOTT.FOREIGN_SUB to SCOTT.FOREIGN_SUB OCI Error ORA-01403: no data found, SQL .
2013-12-26 04:52:20  WARNING OGG-01003  Oracle GoldenGate Delivery for Oracle, rep_app.prm:  Repositioning to rba 17426 in seqno 29.
2013-12-26 04:52:20  ERROR   OGG-01296  Oracle GoldenGate Delivery for Oracle, rep_app.prm:  Error mapping from SCOTT.FOREIGN_SUB to SCOTT.FOREIGN_SUB.
2013-12-26 04:52:20  WARNING OGG-01525  Oracle GoldenGate Delivery for Oracle, rep_app.prm:  Failed to open trace output file, 'gglog-REP_APP.dmp', error 13 (Permission denied).
2013-12-26 04:52:20  ERROR   OGG-01668  Oracle GoldenGate Delivery for Oracle, rep_app.prm:  PROCESS ABENDING.

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