Re: execute block like Firebird does - Mailing list pgsql-general

From Félix GERZAGUET
Subject Re: execute block like Firebird does
Date
Msg-id CANVwZtsGAYMugW+W7WGGH7Ck3YFV4zB6NvnkwRBXi14XQdpaug@mail.gmail.com
Whole thread Raw
In response to Re: execute block like Firebird does  (PegoraroF10 <marcos@f10.com.br>)
Responses Re: execute block like Firebird does
List pgsql-general
Hello,

On Wed, May 30, 2018 at 2:50 PM, PegoraroF10 <marcos@f10.com.br> wrote:
How to send a script to server and return one or more values from that
execution ?

You´ll probably answer me that I could solve that with a function. But
suppose those executions are dynamic, depends on businness rules or any
other problem.

So, is that possible to change a DO structure is ran, to be possible to
return one or more values ?
It would be like ...
DO returns(ID Integer, Description Text) as
$$
begin
  select ...
  insert ...
  select ... into ID, Description
end
$$

Using this way would be possible to create that script on client, call it
just one time and have a result for that execution, exactly the way a
"execute block" does on Firebird.

Is that possible or there is a way to call just one time the server to
return values without creating a function to each call ?

What do you think change how DO structure is ran to have results from ?
Version 12, what do you think ?

Since you seems to be able to construct dynamically the statement from the client application, I think it is already possible to do that in one SQL statement using CTE.

For example:

Assuming we have the follwing schema:

create table t(c1 text, c2 text);

You can then do:

with stmt1 as (
  select c1, c2 from t
  union all
  select 'value1', 'value2'
)
, stmt2 as (
  insert into t
   select s.c1, s.c2
     from stmt1 s
returning c1
)
select *
  from stmt2
;

So you can construct arbitrary complex thing using any combination of SELECT, UPDATE and DELETE.

Félix

 

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