Обсуждение: Updating Arrays

On Mon, Aug 22, 2011 at 12:54 PM, Bob Pawley <rjpawley@shaw.ca> wrote:
> Hi
>
> I exploring the use of arrays.
>
> So far I have created a table and inserted a row and updated the row with an
> array
> Update library.compare
>   set _base =
>   '{2, 0.764149497122068, 4.8886}'
>   where process_id = 2;
> – successfully.
>
> However when I attempt to update a specific element of the array
>
> Update library.compare
> set _base[2] =
> '{2}'
> where process_id = 2;
> I get an error “invalid input syntax for type numeric: "{2}"”

try "set base[2]  = 2"

merlin

I'm not sure what you mean.

_base -- not base -- is the column name.

Bob

-----Original Message-----
From: Merlin Moncure
Sent: Monday, August 22, 2011 11:03 AM
To: Bob Pawley
Cc: Postgresql
Subject: Re: [GENERAL] Updating Arrays

On Mon, Aug 22, 2011 at 12:54 PM, Bob Pawley <rjpawley@shaw.ca> wrote:
> Hi
>
> I exploring the use of arrays.
>
> So far I have created a table and inserted a row and updated the row with
> an
> array
> Update library.compare
>   set _base =
>   '{2, 0.764149497122068, 4.8886}'
>   where process_id = 2;
> – successfully.
>
> However when I attempt to update a specific element of the array
>
> Update library.compare
> set _base[2] =
> '{2}'
> where process_id = 2;
> I get an error “invalid input syntax for type numeric: "{2}"”

try "set base[2]  = 2"

merlin

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> -----Original Message----- From: Merlin Moncure
> Sent: Monday, August 22, 2011 11:03 AM
> To: Bob Pawley
> Cc: Postgresql
> Subject: Re: [GENERAL] Updating Arrays
>
> On Mon, Aug 22, 2011 at 12:54 PM, Bob Pawley <rjpawley@shaw.ca> wrote:
>>
>> Hi
>>
>> I exploring the use of arrays.
>>
>> So far I have created a table and inserted a row and updated the row with
>> an
>> array
>> Update library.compare
>>  set _base =
>>  '{2, 0.764149497122068, 4.8886}'
>>  where process_id = 2;
>> – successfully.
>>
>> However when I attempt to update a specific element of the array
>>
>> Update library.compare
>> set _base[2] =
>> '{2}'
>> where process_id = 2;
>> I get an error “invalid input syntax for type numeric: "{2}"”
>
> try "set base[2]  = 2"
>
On Mon, Aug 22, 2011 at 8:49 PM, Bob Pawley <rjpawley@shaw.ca> wrote:
> I'm not sure what you mean.
>
> _base -- not base -- is the column name.

oops. anyways, the important point is on the right side of the equals sign.

Update library.compare set _base[2] = 2 where process_id = 2;

(also, please try to avoid top posting)

merlin

> -----Original Message----- From: Merlin Moncure
> Sent: Monday, August 22, 2011 11:03 AM
> To: Bob Pawley
> Cc: Postgresql
> Subject: Re: [GENERAL] Updating Arrays
>
> On Mon, Aug 22, 2011 at 12:54 PM, Bob Pawley <rjpawley@shaw.ca> wrote:
>> Hi
>>
>> I exploring the use of arrays.
>>
>> So far I have created a table and inserted a row and updated the row with an
>> array
>> Update library.compare
>>  set _base =
>>  '{2, 0.764149497122068, 4.8886}'
>>  where process_id = 2;
>> – successfully.
>>
>> However when I attempt to update a specific element of the array
>>
>> Update library.compare
>> set _base[2] =
>> '{2}'
>> where process_id = 2;
>> I get an error “invalid input syntax for type numeric: "{2}"”
>
> try "set base[2]  = 2"
>
> merlin
>
> On Aug 22, 2011, at 21:49, "Bob Pawley" <rjpawley@shaw.ca> wrote:

> I'm not sure what you mean.
>
> _base -- not base -- is the column name.
>
> Bob

Your column name has a leading underscore? On the table or is it an alias? Regardless is it that hard to replace the
mis-typedcolumn name with the correct one? 

Compare these statements:
Original
... Set base = {1,2,3};
SELECT base[2] ... ;

Updates
Set base[2] = {2};  -- replaces the second value with an array of 1 dimension and a single value.
set base[2] = 2;  -- replaces the second value with a single numeric value

Now, from the above select, is the second value an array or a single value?

And please do not top-post.  Personally it isn't that big a deal to me but since the first reply was bottom posted you
shouldfollow suit.  Even when you reply first on this list it is customary to bottom-post.  When in Rome... 

David J.

Merlin Moncure <mmoncure@gmail.com> writes:
> On Mon, Aug 22, 2011 at 8:49 PM, Bob Pawley <rjpawley@shaw.ca> wrote:
>> I'm not sure what you mean.
>> _base -- not base -- is the column name.

> oops. anyways, the important point is on the right side of the equals sign.
> Update library.compare set _base[2] = 2 where process_id = 2;

Right.  If you assign to _base[2], you must provide a single numeric
value.  Not a one-element array.

OTOH, if you were to assign to _base[2:2] (an array slice containing
just that one element), you must provide a one-element numeric array on
the righthand side.  So if there's some reason why you need to write
'{2}' and not just '2', you can accommodate that by adjusting what
you're assigning to.

            regards, tom lane