AW: [HACKERS] Please advise features in 7.1 (SUMMARY)

[Zeugswetter Andreas SB]

  This is a summary of replies.
  
  1. Calculated fields in table definitions . eg.
  
  Create table test (
   A Integer,
   B integer,
  the_sum   As  (A+B),
  );
  
  This functionality can be achieved through the use of views.
 
 Using a view for this isn't quite the same functionality as a computed
 field, from what I understand, since the calculation will be done at
 SELECT time, rather than INSERT/UPDATE.

I would expect the calculated field from above example to be calculated
during select time also, no ? You don't want to waste disk space with something 
you can easily compute at runtime.

Andreas

AW: [HACKERS] Please advise features in 7.1

[Zeugswetter Andreas SB]

 Reason: I want to know if any of these features are scheduled.
 
 1. Calculated fields in table definitions . eg.
 
Create table test (
 A Integer,
 B integer,
the_sum   As  (A+B),
 );

This is currently easily done with a procedure that takes a tabletype parameter
with the name the_sum returning the sum of a + b.

   Create table test (
 A Integer,
 B integer
);

create function the_sum (test) returns integer as
'
begin;
return ($1.a + $1.b);
end;
' language 'plpgsql';

A select * won't return the_sum, but a 
select t.a, t.b, t.the_sum from test t; 
will do what you want.

Unfortunately it only works if you qualify the column the_sum with a tablename or 
alias.
(But I heard you mention the Micro$oft word, and they tend to always use aliases 
anyway)
Maybe we could even extend the column search in the unqualified case ?

Andreas

Re: AW: [HACKERS] Please advise features in 7.1

[Don Baccus]

At 12:28 PM 11/23/00 +0100, Zeugswetter Andreas SB wrote:

 Reason: I want to know if any of these features are scheduled.
 
 1. Calculated fields in table definitions . eg.
 
Create table test (
 A Integer,
 B integer,
the_sum   As  (A+B),
 );

This is currently easily done with a procedure that takes a tabletype
parameter
with the name the_sum returning the sum of a + b.

   Create table test (
 A Integer,
 B integer
);

create function the_sum (test) returns integer as
'
   begin;
   return ($1.a + $1.b);
   end;
' language 'plpgsql';

A select * won't return the_sum

create view test2 select A, B, A+B as the_sum from test;

will, though.

See, lots of ways to do it!



- Don Baccus, Portland OR [EMAIL PROTECTED]
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