You check uniqueness on the PK. don't make a functionally dependent unique index and you will check uniqueness only once. On Mon, Jun 22, 2015 at 7:42 PM, Roberto Spadim <roberto@spadim.com.br> wrote:
at insert, update and replace
2015-06-22 23:39 GMT-03:00 Justin Swanhart <greenlion@gmail.com>:
Hi,
If you do a code inspection you will find that uniqueness is checked on insertion, and the database cares not about it after that.
--Justin
On Mon, Jun 22, 2015 at 7:20 PM, Roberto Spadim <roberto@spadim.com.br> wrote:
and there's optimization with this flag? i see that equal could be optimized cause if we found 1 row we can return to user that row and stop select
in other words, if i see a index with primary key or unique columns, could i change the index to unique and get some kind of performace? today i think not ,cause unique key check if it's really unique (for example at insert/update/replace), i'm wrong?
-- Roberto Spadim SPAEmpresarial - Software ERP Eng. Automação e Controle