note
Dominus
Says [princepawn]:
<blockquote><i>
> How does one write Perl code such that it can work<br>
> without modification in the face of labeling,<br>
> destructive, or positional field mutations?
</i></blockquote>
It's going to take a lot of effort to do it in Perl
or in any other language.
Here's a small table with only two columns:
<code>
ID1 ID2
-----------
119 666
437 112
</code>
Now switch the order of the two columns,
and change the names so that ID1 is now called ID2 and ID2 is now called ID1:
<code>
ID1 ID2
-----------
666 119
112 437
</code>
Now how are you going to write a program that magically copes with that?
This is not a Perl problem; it's an impossible problem.
Even looking at the database schema is not going to work.
<p>
The only solution is for the database itself to carry its own
description. One way is to install a special row
into each table:
<code>
ID1 ID2
-----------
"id2" "id1"
... ...
</code>
then the program can select this row, examine it to
see whether the column names or the order have changed,
and it can make the appropriate allowances.
43748
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