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Message Posted: Mon, 23 Jul 2012 @ 11:07:36 GMT
It seems to be true but not the whole true !
Let's analyze such example:
create volatile set table upiset ( n integer, c char(1) ) unique primary index ( n); insert into upiset select a,c from ( sel 1 a, 'X' c ) t1 union all select a,c from ( sel 1 a, 'X' c ) t2 ; result : INSERT completed. 1 rows processed (not an error !!!)
It means, than - if rows are inserted in one statement - TD first compares the whole row and in case of double silently eliminates second and next identical rows instead of generating error 2801 (Duplicate unique primary key).
I believe, that actually algorithm is better:
- first check if PI columns are unique
- if not, compare the whole row and if such row exists ignore it.
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