合并更新时间 [英] Merge update Temporal

问题描述

表测试中的现有数据:(临时表)

Existing data in table test : (Temporal table)

id name    valid_dt
1  cat     2012-06-16 - 9999-12-31

传入表:(临时)

  id name  valid_dt
  1  bat   2013-12-28 - 9999-12-31

合并更新后，测试表应具有

After Merge update , test table should have

id name valid_dt
1 cat    2012-06-16 - 2013-12-28
1 bat    2013-12-28 - 9999-12-31

如果我今天运行它，Teradata临时合并更新语句是否可能?

Will It be possible in Teradata Temporal Merge update statement if i run it today?

我尝试过的无效代码

SEQUENCED VALIDTIME 
MERGE INTO  test
USING    
(  
  sel * from incoming 
) H on id=H.id
when matched then
update  
set name = h.name
;

更新尝试dnoeths解决方案后: 要删除:

UPDATE After trying dnoeths solution: For delete :

在我的实际传入表中，实际上已关闭了一些记录.

In my real incoming table some records were actually closed .

所以我需要硬代码的结束日期，直到until_changed

so i need hard code end date as until_changed

无效删除:

sequenced validtime
delete from test where (cust_id,name) in
(nonsequenced validtime
 select id,name,period(begin(valid_dt),until_changed)
from incoming );

推荐答案

AFAIK，您需要执行两步过程来维护这样的ValidTime表:先是先后执行先后顺序的ValidTime DELETE和未顺序的ValidTime INSERT:

AFAIK you need to a two step process to maintain a ValidTime table like this, a Sequenced ValidTime DELETE followed by a NonSequenced ValidTime INSERT:

SEQUENCED VALIDTIME 
DELETE test FROM incoming
WHERE test.id = incoming.id
;NONSEQUENCED VALIDTIME
INSERT INTO test SELECT * FROM incoming;

应该可以用合并替换插入/选择，但是您仍然需要先删除:

Replacing the Insert/Select with Merge should be possible, but you still need the Delete first:

NONSEQUENCED VALIDTIME 
MERGE INTO  test
USING    
(  
  sel * from incoming 
) H ON test.id=H.id
AND test.valid_dt = h.valid_dt
WHEN NOT MATCHED THEN
INSERT (H.id, H.name, h.valid_dt)  

像非时间DML一样，MERGE可能比插入/选择或更新更有效.

Like non-temporal DML the MERGE might be more efficient than Insert/Select or Update.

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