Thread: Database/Table Design for Global Country Statistics

Database/Table Design for Global Country Statistics

From
Stefan Schwarzer
Date:
Hi there,

I learned in another posting that my table design - in a polite way -
"could be improved".

So, before doing any additional design errors, I would like to get
feedback, if possible.

I am dealing with some 500 tables for worldwide national statistics
(GDP, population, environment etc.), covering approx. 30 years each.
For each of these variables, I usually have as well (pre-prepared)
subregional and regional aggregations too. These could - and should -
at the end be calculated on-the-fly, and not pre-calculated and
imported from Excel as it is for the moment.

My (national) table for a given variable is in the moment as follows
(id being the identifier for a specific country):

id   |    1970    |    1971    |    ...    |    2004    |    2005
-------------------------------------------------------------------
  1   |   NULL    |      36       |   ...     |      42      |      45
  2 ......

The new design would be like this:

id   |    year    |    value
-------------------------------
  1   |   1970    |     NULL
  1   |   1971    |      36
  1   ....
  1   |   2005    |      45
  2   |   1970    |      ....
  2   .....


Would that be considered as "good table design" then?

Thanks for any advice!

Stef



Re: Database/Table Design for Global Country Statistics

From
Richard Huxton
Date:
Stefan Schwarzer wrote:
> Hi there,
>
> I learned in another posting that my table design - in a polite way -
> "could be improved".
>
> So, before doing any additional design errors, I would like to get
> feedback, if possible.
>
> I am dealing with some 500 tables for worldwide national statistics
> (GDP, population, environment etc.), covering approx. 30 years each. For
> each of these variables, I usually have as well (pre-prepared)
> subregional and regional aggregations too. These could - and should - at
> the end be calculated on-the-fly, and not pre-calculated and imported
> from Excel as it is for the moment.

Might want a trigger to keep them up to date.

> My (national) table for a given variable is in the moment as follows (id
> being the identifier for a specific country):
>
> id   |    1970    |    1971    |    ...    |    2004    |    2005
> -------------------------------------------------------------------
>  1   |   NULL    |      36       |   ...     |      42      |      45
>  2 ......

Ick - fiddly if you we ever reach 2006...

> The new design would be like this:
>
> id   |    year    |    value
> -------------------------------
>  1   |   1970    |     NULL
>  1   |   1971    |      36
>  1   ....
>  1   |   2005    |      45
>  2   |   1970    |      ....
>  2   .....
>
>
> Would that be considered as "good table design" then?

Well if "id" is a country I'd rename it "country_id".

If all years+countries should have the same set of measurements you
might want it in one table:
  (country_id, year, population, area, roads_in_km, ...)

However, if some measurements aren't relevant you're probably better off
with separate table for each measurement: country_population,
country_area etc.

The issue with NULLs is what do they mean. They should mean "unknown",
nothing more and nothing less. However, frequently you want to
distinguish between "no figure available" and "not applicable" (e.g.
"monarch" isn't relevant except in monarchies).

In this case it's probably best practice to separate out the values:
  (country_id integer, year integer, has_monarch boolean, monarch text)
This way you can distinguish between has_monarch=false and monarch=''

--
   Richard Huxton
   Archonet Ltd

Re: Database/Table Design for Global Country Statistics

From
Tino Wildenhain
Date:
Stefan Schwarzer schrieb:
> Hi there,
>
> I learned in another posting that my table design - in a polite way -
> "could be improved".
>
> So, before doing any additional design errors, I would like to get
> feedback, if possible.
>
> I am dealing with some 500 tables for worldwide national statistics
> (GDP, population, environment etc.), covering approx. 30 years each. For
> each of these variables, I usually have as well (pre-prepared)
> subregional and regional aggregations too. These could - and should - at
> the end be calculated on-the-fly, and not pre-calculated and imported
> from Excel as it is for the moment.
>
> My (national) table for a given variable is in the moment as follows (id
> being the identifier for a specific country):
>
> id   |    1970    |    1971    |    ...    |    2004    |    2005
> -------------------------------------------------------------------
>  1   |   NULL    |      36       |   ...     |      42      |      45
>  2 ......
>
> The new design would be like this:
>
> id   |    year    |    value
> -------------------------------
>  1   |   1970    |     NULL
>  1   |   1971    |      36
>  1   ....
>  1   |   2005    |      45
>  2   |   1970    |      ....
>  2   .....
>
>
> Would that be considered as "good table design" then?

I'd not save null values but otherwise you are fine.
If you want to select over stable ranges of years
w/o bothering with non existent data (and therefore year)
it might be usefull to have a separate mapping table like
year -> year_id (sequential) and use the Ids for year.

This can even be simplified to a table just providing you the
coverage of years you have as a whole and use the number
directly as foreign key in your table.

table:years

year
1970
1971
1972
...


table:measures
measure_id,description
1          foovar
2          barvar
...


table:values
year (fk from years), measure_id (fk from measures), value
1971                  1                              36


every column of "values" table would be not null and
primary key (year,measure_id)

This way you can easily create any report you want
by selectiong a year range, then left join the values table
as often as you want for a given measure and so on.

Regards
Tino




Re: Database/Table Design for Global Country Statistics

From
Ron Johnson
Date:
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 09/12/07 03:28, Stefan Schwarzer wrote:
[snip]
>
> The new design would be like this:
>
> id   |    year    |    value
> -------------------------------
>  1   |   1970    |     NULL
>  1   |   1971    |      36
>  1   ....
>  1   |   2005    |      45
>  2   |   1970    |      ....
>  2   .....
>
>
> Would that be considered as "good table design" then?

What Richard says, plus:

1. The PK of New_Design should be country_id/year.

2. You also should not store the records where "value is NULL".  A
left outer join would handle that.

- --
Ron Johnson, Jr.
Jefferson LA  USA

Give a man a fish, and he eats for a day.
Hit him with a fish, and he goes away for good!

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.6 (GNU/Linux)

iD8DBQFG57E/S9HxQb37XmcRAsb/AJ97lFt25sLwIYhkhQgGdJq2m8NaXgCfTxIV
rVuX5FF0XRDkXJgdSlV1qZg=
=jyv3
-----END PGP SIGNATURE-----

Re: Database/Table Design for Global Country Statistics

From
Stefan Schwarzer
Date:
Thanks for the feedback and the suggestions.

A problem I have now when using the new design is the following:

As a result from my PostGres query I get something like this:

     year    |    value     |    name
---------------------------------------
    2001    |     123       |   Afghanistan
    2002    |     125       |   Afghanistan
    2003    |     128       |   Afghanistan
    2004    |     132       |   Afghanistan
    2005    |     135       |   Afghanistan

    2001    |     412       |   Albania
    2002    |     429       |   Albania
    2003    |     456       |   Albania
    2004    |     465       |   Albania
    2005    |     477       |   Albania

.....


The way it is displayed on the web (in table form) is the "usual" way:

     name             2001    2002   2003   2004   2005
-----------------------------------------------------------------
Afghanistan    ....
Albania            ....


Is there any "simple", elegant solution for PHP, so that it does this
transformation? I can't imagine that I would have to write a couple
of IFs to achieve that. But I have no other idea. Or is it a question
of writing a more elegant SQL query?

Thanks for any advice!

Stef



Re: Database/Table Design for Global Country Statistics

From
Richard Huxton
Date:
Stefan Schwarzer wrote:
> Thanks for the feedback and the suggestions.
>
> A problem I have now when using the new design is the following:
>
> As a result from my PostGres query I get something like this:
>
>     year    |    value     |    name
> ---------------------------------------
>    2001    |     123       |   Afghanistan
>    2002    |     125       |   Afghanistan
>    2003    |     128       |   Afghanistan
[etc]
> The way it is displayed on the web (in table form) is the "usual" way:
>
>     name             2001    2002   2003   2004   2005
> -----------------------------------------------------------------
> Afghanistan    ....
> Albania            ....
>
>
> Is there any "simple", elegant solution for PHP, so that it does this
> transformation? I can't imagine that I would have to write a couple of
> IFs to achieve that. But I have no other idea. Or is it a question of
> writing a more elegant SQL query?

$curr_yr = -1
$cols = array();
while (<fetch rows>) {
   if ($row['year'] != $curr_yr) {
     if (sizeof($cols) > 0) { display_table_row($cols); }
     $cols = array();
     $curr_year = $row['year'];
   }
   $cols[] = $row['value'];
}
// handle possible last row of table
if (sizeof($cols) > 0) { display_table_row($cols); }


Make sure your query is ordered properly and you don't have gaps in your
years.

--
   Richard Huxton
   Archonet Ltd

Re: Database/Table Design for Global Country Statistics

From
Stefan Schwarzer
Date:
Many, many thanks for that and the other advices from everybody.
You're great!

As I am neither expert in PHP, nor in Postgres, MySQL, Javascript,
HTML etc. etc., all I do in the forums is asking questions; and not
"adding value" by helping others (due to my limited knowledge). All I
can do is offer you a moment of relaxation by looking at some really
nice nature/landscape photos @ http://photoblog.la-famille-schwarzer.de

Cheers,

Stef


On Sep 12, 2007, at 11:45 AM, Richard Huxton wrote:

> Stefan Schwarzer wrote:
>> Thanks for the feedback and the suggestions.
>> A problem I have now when using the new design is the following:
>> As a result from my PostGres query I get something like this:
>>     year    |    value     |    name
>> ---------------------------------------
>>    2001    |     123       |   Afghanistan
>>    2002    |     125       |   Afghanistan
>>    2003    |     128       |   Afghanistan
> [etc]
>> The way it is displayed on the web (in table form) is the "usual"
>> way:
>>     name             2001    2002   2003   2004   2005
>> -----------------------------------------------------------------
>> Afghanistan    ....
>> Albania            ....
>> Is there any "simple", elegant solution for PHP, so that it does
>> this transformation? I can't imagine that I would have to write a
>> couple of IFs to achieve that. But I have no other idea. Or is it
>> a question of writing a more elegant SQL query?
>
> $curr_yr = -1
> $cols = array();
> while (<fetch rows>) {
>   if ($row['year'] != $curr_yr) {
>     if (sizeof($cols) > 0) { display_table_row($cols); }
>     $cols = array();
>     $curr_year = $row['year'];
>   }
>   $cols[] = $row['value'];
> }
> // handle possible last row of table
> if (sizeof($cols) > 0) { display_table_row($cols); }
>
>
> Make sure your query is ordered properly and you don't have gaps in
> your years.
>
> --
>   Richard Huxton
>   Archonet Ltd


Re: Database/Table Design for Global Country Statistics

From
Richard Huxton
Date:
Stefan Schwarzer wrote:
> Many, many thanks for that and the other advices from everybody. You're
> great!
>
> As I am neither expert in PHP, nor in Postgres, MySQL, Javascript, HTML
> etc. etc., all I do in the forums is asking questions; and not "adding
> value" by helping others (due to my limited knowledge). All I can do is
> offer you a moment of relaxation by looking at some really nice
> nature/landscape photos @ http://photoblog.la-famille-schwarzer.de

There's always the pgsql-novice mailing list, I'm sure you could be of
assistance there.

--
   Richard Huxton
   Archonet Ltd

Re: Database/Table Design for Global Country Statistics

From
Stefan Schwarzer
Date:
> $curr_yr = -1
> $cols = array();
> while (<fetch rows>) {
>   if ($row['year'] != $curr_yr) {
>     if (sizeof($cols) > 0) { display_table_row($cols); }
>     $cols = array();
>     $curr_year = $row['year'];
>   }
>   $cols[] = $row['value'];
> }
> // handle possible last row of table
> if (sizeof($cols) > 0) { display_table_row($cols); }
>

Thanks for the code. I got it working with a couple of changes. But
then I realized that with the new table design I can't anymore easily
sort by a given year (1970 or 2000). This is surely one of the
advantages of the "old" design, that the use via PHP was quite
straight forward.

Do I have to transfer the query results into a PHP array to sort it
in there, then?

Thanks for any hints!

Stef


Re: Database/Table Design for Global Country Statistics

From
Richard Huxton
Date:
Stefan Schwarzer wrote:
>> $curr_yr = -1
>> $cols = array();
>> while (<fetch rows>) {
>>   if ($row['year'] != $curr_yr) {
>>     if (sizeof($cols) > 0) { display_table_row($cols); }
>>     $cols = array();
>>     $curr_year = $row['year'];
>>   }
>>   $cols[] = $row['value'];
>> }
>> // handle possible last row of table
>> if (sizeof($cols) > 0) { display_table_row($cols); }
>>
>
> Thanks for the code. I got it working with a couple of changes. But then
> I realized that with the new table design I can't anymore easily sort by
> a given year (1970 or 2000). This is surely one of the advantages of the
> "old" design, that the use via PHP was quite straight forward.
>
> Do I have to transfer the query results into a PHP array to sort it in
> there, then?

Umm - not sure what you're after. What's wrong with one of:
   SELECT ... ORDER BY year, value
   SELECT ... ORDER BY value, year

Or did you want a particular year pulled out of the general list, in
which case try something like:
   SELECT ... ORDER BY (year = 1970), year, value
   SELECT ... ORDER BY (year <> 1970), year, value
This works because booleans are considered sortable too.

--
   Richard Huxton
   Archonet Ltd

Re: Database/Table Design for Global Country Statistics

From
Stefan Schwarzer
Date:
>>> $curr_yr = -1
>>> $cols = array();
>>> while (<fetch rows>) {
>>>   if ($row['year'] != $curr_yr) {
>>>     if (sizeof($cols) > 0) { display_table_row($cols); }
>>>     $cols = array();
>>>     $curr_year = $row['year'];
>>>   }
>>>   $cols[] = $row['value'];
>>> }
>>> // handle possible last row of table
>>> if (sizeof($cols) > 0) { display_table_row($cols); }
>>>
>> Thanks for the code. I got it working with a couple of changes.
>> But then I realized that with the new table design I can't anymore
>> easily sort by a given year (1970 or 2000). This is surely one of
>> the advantages of the "old" design, that the use via PHP was quite
>> straight forward.
>> Do I have to transfer the query results into a PHP array to sort
>> it in there, then?
>
> Umm - not sure what you're after. What's wrong with one of:
>   SELECT ... ORDER BY year, value
>   SELECT ... ORDER BY value, year
>
> Or did you want a particular year pulled out of the general list,
> in which case try something like:
>   SELECT ... ORDER BY (year = 1970), year, value
>   SELECT ... ORDER BY (year <> 1970), year, value
> This works because booleans are considered sortable too.

Wow, didn't know about the "(year = 1970)" thing. Cool. But
nevertheless, the problem is then with the PHP code above; a
different sorting in the query result, means as well a different
coding. Or I have completely miscoded your draft. But I don't see how
it would handle a resulting array of any order - by year, by name,
ascending, descending... I guess I need to go with the PHP array, no?

        $current_country = -1;
        $count = -1;
        $cols = array();

        while ($row = pg_fetch_array($result))
        {
            if ($row['name'] != $current_country)
            {
                if (sizeof($cols) > 0)
                {
                    $count++;
                    $code7 .= display_table_row($current_country, $cols, $count,
$selectedDataset -> name, $selectedID, $selectedTime);
                }
                $cols = array();
                $current_country = $row['name'];
            }
            $cols[] = $row['value'];
        }

        // handle possible last row of table
        if (sizeof($cols) > 0)
        {
            $code7 .= display_table_row($current_country, $cols, ($count + 1),
$selectedDataset -> name, $selectedID, $selectedTime);
        }



Re: Database/Table Design for Global Country Statistics

From
Richard Huxton
Date:
Stefan Schwarzer wrote:
>
>>>> $curr_yr = -1
>>>> $cols = array();
>>>> while (<fetch rows>) {
>>>>   if ($row['year'] != $curr_yr) {
>>>>     if (sizeof($cols) > 0) { display_table_row($cols); }
>>>>     $cols = array();
>>>>     $curr_year = $row['year'];
>>>>   }
>>>>   $cols[] = $row['value'];
>>>> }
>>>> // handle possible last row of table
>>>> if (sizeof($cols) > 0) { display_table_row($cols); }
>>>>
>>> Thanks for the code. I got it working with a couple of changes. But
>>> then I realized that with the new table design I can't anymore easily
>>> sort by a given year (1970 or 2000). This is surely one of the
>>> advantages of the "old" design, that the use via PHP was quite
>>> straight forward.
>>> Do I have to transfer the query results into a PHP array to sort it
>>> in there, then?
>>
>> Umm - not sure what you're after. What's wrong with one of:
>>   SELECT ... ORDER BY year, value
>>   SELECT ... ORDER BY value, year
>>
>> Or did you want a particular year pulled out of the general list, in
>> which case try something like:
>>   SELECT ... ORDER BY (year = 1970), year, value
>>   SELECT ... ORDER BY (year <> 1970), year, value
>> This works because booleans are considered sortable too.
>
> Wow, didn't know about the "(year = 1970)" thing. Cool. But
> nevertheless, the problem is then with the PHP code above; a different
> sorting in the query result, means as well a different coding. Or I have
> completely miscoded your draft. But I don't see how it would handle a
> resulting array of any order - by year, by name, ascending,
> descending... I guess I need to go with the PHP array, no?

Ah, I see - your query-results do need to be ordered the same as the
table, yes.

Of course you should really have a data model that knows what it wants
to sort by and constructs the query appropriately. The table-drawing
code can then ask the data-model for heading-names and sort-order
details. It's more work up-front, but you only have to do it once and
then you can generate new table layouts very easily.

--
   Richard Huxton
   Archonet Ltd

Re: Database/Table Design for Global Country Statistics

From
Stefan Schwarzer
Date:
> Umm - not sure what you're after. What's wrong with one of:
>   SELECT ... ORDER BY year, value
>   SELECT ... ORDER BY value, year
>
> Or did you want a particular year pulled out of the general list,
> in which case try something like:
>   SELECT ... ORDER BY (year = 1970), year, value
>   SELECT ... ORDER BY (year <> 1970), year, value
> This works because booleans are considered sortable too.

Uiuiui.... and it gets even worse... I want to implement the
possibility to calculate on-the-fly the per Capita values for the
selected data set. With the "old" table design it would be something
like this:

       SELECT (fish_catch.y_1970 / pop_total.y_1970),
(fish_catch.y_1971 / pop_total.y_1971) FROM .....

But how would this work with the new design?

Sorry for these repeated questions.... (But it's you guys' fault -
you said I had a bad table design.... :-))

Thanks for any hints!

Stef

Re: Database/Table Design for Global Country Statistics

From
Richard Huxton
Date:
Stefan Schwarzer wrote:
>
>> Umm - not sure what you're after. What's wrong with one of:
>>   SELECT ... ORDER BY year, value
>>   SELECT ... ORDER BY value, year
>>
>> Or did you want a particular year pulled out of the general list, in
>> which case try something like:
>>   SELECT ... ORDER BY (year = 1970), year, value
>>   SELECT ... ORDER BY (year <> 1970), year, value
>> This works because booleans are considered sortable too.
>
> Uiuiui.... and it gets even worse... I want to implement the possibility
> to calculate on-the-fly the per Capita values for the selected data set.
> With the "old" table design it would be something like this:
>
>       SELECT (fish_catch.y_1970 / pop_total.y_1970), (fish_catch.y_1971
> / pop_total.y_1971) FROM .....

SELECT
    year,
    country,
    fish_catch,
    pop_total,
    (fish_catch / pop_total) AS fish_per_capita
FROM my_table
ORDER BY year,country

Or, if the fish + population data are in different tables:

SELECT
   f.year,
   f.country,
   f.fish_catch
   p.pop_total
   (f.fish_catch / p.pop_total) AS fish_per_capita
FROM
   fish_figures f
JOIN
   popn_figures p
USING (year, country)
ORDER BY f.year, f.country;

HTH
--
   Richard Huxton
   Archonet Ltd

Re: Database/Table Design for Global Country Statistics

From
Stefan Schwarzer
Date:
>> Uiuiui.... and it gets even worse... I want to implement the
>> possibility to calculate on-the-fly the per Capita values for the
>> selected data set. With the "old" table design it would be
>> something like this:
>>       SELECT (fish_catch.y_1970 / pop_total.y_1970),
>> (fish_catch.y_1971 / pop_total.y_1971) FROM .....
>
> Or, if the fish + population data are in different tables:
>
> SELECT
>   f.year,
>   f.country,
>   f.fish_catch
>   p.pop_total
>   (f.fish_catch / p.pop_total) AS fish_per_capita
> FROM
>   fish_figures f
> JOIN
>   popn_figures p
> USING (year, country)
> ORDER BY f.year, f.country;
>

Muchos gracias, Mr. Postgres! I am really touched by your help!

Just for the completeness, I attach the final working SQL query:

SELECT
   f.year,
   f.id,
   c.name,
   (f.value / p.value) AS per_capita
FROM
   fish_catch AS f
JOIN
   pop_total AS p
USING
    (year, id)
INNER JOIN
    countries AS c ON f.id = c.id
ORDER BY
    year

Re: Database/Table Design for Global Country Statistics

From
Richard Huxton
Date:
Stefan Schwarzer wrote:
> Just for the completeness, I attach the final working SQL query:
>
> SELECT
>   f.year,
>   f.id,
>   c.name,
>   (f.value / p.value) AS per_capita
> FROM
>   fish_catch AS f
> JOIN
>   pop_total AS p
> USING
>    (year, id)
> INNER JOIN
>    countries AS c ON f.id = c.id
> ORDER BY
>    year

Make sure you fully specify the order:
   ORDER BY year, f.id, c.name
It might work by chance a few times, but then return rows in an
unexpected order later.

--
   Richard Huxton
   Archonet Ltd

Data Model - Linking to PHP Code - Literature

From
Stefan Schwarzer
Date:
> Of course you should really have a data model that knows what it
> wants to sort by and constructs the query appropriately. The table-
> drawing code can then ask the data-model for heading-names and sort-
> order details. It's more work up-front, but you only have to do it
> once and then you can generate new table layouts very easily.

Can you recommend some literature for this subject? Tutorials or
something online? I know what a data model is. But I have no idea how
"the table-drawing code can then ask the data model"....

Many thanks!

Stef

Re: Data Model - Linking to PHP Code - Literature

From
Richard Huxton
Date:
Stefan Schwarzer wrote:
>
>> Of course you should really have a data model that knows what it wants
>> to sort by and constructs the query appropriately. The table-drawing
>> code can then ask the data-model for heading-names and sort-order
>> details. It's more work up-front, but you only have to do it once and
>> then you can generate new table layouts very easily.
>
> Can you recommend some literature for this subject? Tutorials or
> something online? I know what a data model is. But I have no idea how
> "the table-drawing code can then ask the data model"....

Google around for "metadata" and "data driven/led development"

Basically your data model needs to be able to describe itself in enough
detail that your code can draw it without having to have lots of
parameters set.

--
   Richard Huxton
   Archonet Ltd

Re: Database/Table Design for Global Country Statistics

From
Stefan Schwarzer
Date:
SELECT
   f.year,
   f.id,
   c.name,
   (f.value / p.value) AS per_capita
FROM
   fish_catch AS f
JOIN
   pop_total AS p
USING
    (year, id)
INNER JOIN
    countries AS c ON f.id = c.id
ORDER BY
    (year = 2005), value, name


Seems to never end.... Why is redesigning tables so difficult?! :-))

And furthermore, it is really difficult to grab and formulate the
problem that I have now. Let's see:

The above SQL leads to a correct SQL result; but the "(year = 2005)"
changes the "pattern" of the output completely. Before, without
sorting by a specific year, it would look like this:

year    value    name
1995    NULL    Afghanistan
2000    NULL    Afghanistan
2005    NULL    Afghanistan
2000    2365    Albania
2005    2065    Albania
1995    1160    Albania
2000    113157    Algeria
2005    126259    Algeria
1995    105872    Algeria
2000    832        American Samoa
2005    3943    American Samoa
1995    152     American Samoa

With specifying "ORDER BY (y_2005), value, name" I have this:

year    value    name
1995    0    Ethiopia
2000    0    Ethiopia
2000    0.5    Bosnia and Herzegovina
1995    0.5    Bosnia and Herzegovina
2000    0.5    Christmas Island
1995    0.5    Christmas Island
....
2005    0    Bosnia and Herzegovina
2005    0    Ethiopia
2005    0.5    Christmas Island
2005    0.5    Cocos (Keeling) Islands

But what I would need is this:

1995    0.5    Bosnia and Herzegovina
2000    0.5    Bosnia and Herzegovina
2005    0    Bosnia and Herzegovina
1995    0    Ethiopia
2000    0    Ethiopia
2005    0    Ethiopia
1995    0.5    Christmas Island
2000    0.5    Christmas Island
2005    0.5    Christmas Island

Looks similar to the first result, but all content would be sorted by
the year 2005 without separating it from the other years.

Hmmm.... don't know if this is clear...

Most grateful for any feedback,

Stef