Обсуждение: Rules versus triggers
Could someone give me a brief description of the intended functionally, and
how the 2 features work of rules, versus triggers? It appears to me that
they are simply 2 different ways to set up triggers, but I am certain that
is just because of my lack of knowledge.
Thank you.
--
"They that would give up essential liberty for temporary safety deserve
neither liberty nor safety."
-- Benjamin Franklin
On 07/03/2020 11:56, stan wrote: > Could someone give me a brief description of the intended functionally, and > how the 2 features work of rules, versus triggers? It appears to me that > they are simply 2 different ways to set up triggers, but I am certain that > is just because of my lack of knowledge. The pages https://wiki.postgresql.org/wiki/Don%27t_Do_This#Don.27t_use_rules links to will give you some idea of the differences. Cheers, Steve
Hi Stan
Rules actual are able to rewrite the SQL query sent to postgresql. Most everyone suggestion is avoid rules.
Triggers are just like every other databases Triggers firing off code for Insert/Update/Delete/Truncate event
On Sat, Mar 7, 2020 at 6:56 AM stan <stanb@panix.com> wrote:
Could someone give me a brief description of the intended functionally, and
how the 2 features work of rules, versus triggers? It appears to me that
they are simply 2 different ways to set up triggers, but I am certain that
is just because of my lack of knowledge.
Thank you.
--
"They that would give up essential liberty for temporary safety deserve
neither liberty nor safety."
-- Benjamin Franklin
On Sat, Mar 07, 2020 at 09:47:39AM -0500, Justin wrote: > Hi Stan > > Rules actual are able to rewrite the SQL query sent to postgresql. Most > everyone suggestion is avoid rules. > > Triggers are just like every other databases Triggers firing off code for > Insert/Update/Delete/Truncate event > https://www.postgresql.org/docs/current/sql-createtrigger.html > So, the RULE can actually rewrite the query, instead of replacing it, which is what I m doing in the function, correct? -- "They that would give up essential liberty for temporary safety deserve neither liberty nor safety." -- Benjamin Franklin
Yes a rule can rewrite query or replace the query
Read through Depesz post about rules and the weird side affects that can occurr
On Sat, Mar 7, 2020 at 9:57 AM stan <stanb@panix.com> wrote:
On Sat, Mar 07, 2020 at 09:47:39AM -0500, Justin wrote:
> Hi Stan
>
> Rules actual are able to rewrite the SQL query sent to postgresql. Most
> everyone suggestion is avoid rules.
>
> Triggers are just like every other databases Triggers firing off code for
> Insert/Update/Delete/Truncate event
> https://www.postgresql.org/docs/current/sql-createtrigger.html
>
So, the RULE can actually rewrite the query, instead of replacing it,
which is what I m doing in the function, correct?
--
"They that would give up essential liberty for temporary safety deserve
neither liberty nor safety."
-- Benjamin Franklin
On 7/3/20 5:01 μ.μ., Justin wrote:
IMHO Rules are cool. It allows for more elegant design (vs doing it otherwise) and it results in faster queries. In our system we have currently 61 rules and 331 triggers.Yes a rule can rewrite query or replace the queryRead through Depesz post about rules and the weird side affects that can occurr
On Sat, Mar 7, 2020 at 9:57 AM stan <stanb@panix.com> wrote:On Sat, Mar 07, 2020 at 09:47:39AM -0500, Justin wrote:
> Hi Stan
>
> Rules actual are able to rewrite the SQL query sent to postgresql. Most
> everyone suggestion is avoid rules.
>
> Triggers are just like every other databases Triggers firing off code for
> Insert/Update/Delete/Truncate event
> https://www.postgresql.org/docs/current/sql-createtrigger.html
>
So, the RULE can actually rewrite the query, instead of replacing it,
which is what I m doing in the function, correct?
--
"They that would give up essential liberty for temporary safety deserve
neither liberty nor safety."
-- Benjamin Franklin
-- Achilleas Mantzios IT DEV Lead IT DEPT Dynacom Tankers Mgmt