Hi,
Since Canada Post hasn't programmed their automated web tools for calculating
transportation costs to work with anything outside of Windows Internet Explorer, I'm
obliged to write a web based program optimized for all those *other* browsers, myself.
Part of this task requires that I set up tables in postgresql that match postal codes
to transportation cost.
Canada Post provides a booklet for calculating transportation cost based on package
weight and the first three characters of the postal code sequence. For instance, if I
want to send a package to an address that includes G8F 1X1 as the postal code, I take
the first 3 characters G8F and look them up in table 1.
Table 1
PostalCode Tarrif number
---------------------------
G4V 14
G8E-G8G 14
G4R-G4S 13
Since G8F falls in the G8E-G8G range, I now know that the tarrif number is 14. Taking
the number 14, I go to table 2
Table 2
For tarrif Code 14
Weight(kg) Price
----------------------
1.0 5.37
1.5 5.61
2.0 5.82
If the weight of my package is 1kg, the price is 5.37 to send the package to the
address bearing G8F as the first 3 characters of the postal code.
To render this in the database, I have done the following:
_____________________________
p_code |
=============================
pcode_id | tarrif |
-----------------------------
G4V | 14 |
-----------------------------
G8E | 14 |
-----------------------------
G8F | 14 |
-----------------------------
G8G | 14 |
-----------------------------
G4R | 13 |
-----------------------------
G4S | 13 |
-----------------------------
__________________________________
price_weight |
==================================
tarrif | weight(kg)| price |
----------------------------------
14 | 1.0 | 5.37 |
----------------------------------
14 | 1.5 | 5.61 |
----------------------------------
14 | 2.0 | 5.82 |
----------------------------------
13 | 1.0 | 5.20 |
----------------------------------
13 | 1.5 | 5.32 |
----------------------------------
13 | 2.0 | 5.42 |
Therefore my sql statement would look something like this:
SELECT price FROM price_weight
WHERE p_code.tarrif = price_weight.tarrif
AND pcode = 'G8F'
AND weight = '1.0';
I think this will work, but before I proceed, I'd like to ask 2 questions:
1.
Is it possible to further normalize the data in the p_code and price_weight tables
above?
2.
Is it possible to abbreviate the number of records in the p_code table using regular
expressions. For instance, to avoid repetition, I thought I'd use regular expressions,
so that instead of entering the postal code into separate rows as such:
G4V 14
G8E 14
G8F 14
G8G 14
I could do something like this:
(G4V | G8[E-G]) 14
Somehow I don't think this is possible, but I'm looking for any way to minimize the
number of postal codes that I have to enter, since there's a lot of them.
Anyway, I realize these questions may have more to do with database design than
postgresql per se. If there's a better place to ask them, please point me in the right
direction.
Thanks,
Mark
---------------------------(end of broadcast)---------------------------
TIP 7: don't forget to increase your free space map settings
