searching serialized data stored in mysql

hello, i have a table called checkout, this has a row called products
which has contains a python dictionary data, like

http://pastie.org/1082137

{products: [{productId: 123, productName: APPLE,
productPrice: 2.34, productUrl: http://appple-fruits.net,
productDescription: "nice juicy apples"},
{productId: 333, productName: ORANGE,
productPrice: 4.21, productUrl: http://appple-fruits.net,
productDescription: "nice juicy oranges"},
...]}


what will be the correct way to make a search on this data, for
example if i want to search for a range of products with a price
between â‚2 - â‚4

is this the correct way to store this type of data?

thanks
norman

would i have to create a temporary table for each serialized value and
then make my query on this?

--=20
˙uʍop ǝpısdn p,uɹnʇ pןɹoʍ =C7=
É¥Ê=87 ǝǝs noʎ 'ʇuǝɯɐן s=
ǝɯıʇ ǝɥʇ puɐ 'ʇuǝʇuo=
ɔ
ǝq s,ʇǝן ʇǝʎ
%>>> "".join( [ {'*':'@','^':'.'}.get(c,None) or
chr(97+(ord(c)-83)%26) for c in ",adym,*)&uzq^zqf" ] )

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Re: searching serialized data stored in mysql

On 09/08/2010 18:33, Norman Khine wrote:
> hello, i have a table called checkout, this has a row called products
> which has contains a python dictionary data, like
>
> http://pastie.org/1082137
>
> {products: [{productId: 123, productName: APPLE,
> productPrice: 2.34, productUrl: http://appple-fruits.net,
> productDescription: "nice juicy apples"},
> {productId: 333, productName: ORANGE,
> productPrice: 4.21, productUrl: http://appple-fruits.net,
> productDescription: "nice juicy oranges"},
> ...]}
>
>
> what will be the correct way to make a search on this data, for
> example if i want to search for a range of products with a price
> between €2 - €4
>
> is this the correct way to store this type of data?

No, it isn't, not if you're going to be searching for individual
elements of the array. Your products table should really have separate
columns for productId, productName, productPrice, productUrl and
ProductDescription. If you want to be able to store arbitrary key=>value
pairs then a separate table with columns for productId, keyName and
keyValue would be a useful way of doing it.

Storing serialized data in single MySQL column is really only useful if
that data will never be directly manipulated by MySQL itself - that is,
if its only ever being used as the input to a separate program that
handles all the searching and manipulation.

Having said that, I've just looked at the URL you link to
(http://pastie.org/1082137) and what that's demonstrating isn't an
example of a products table, it's an example of a ecommerce checkout
table where the cart contents are a single column of serialized data
within the cart line. Personally, that's not the way I'd do it[1], but
it is a perfectly valid method if you start from the assumption that
you're never going to want to find individual orders by searching the
contents of the order. If you're looking at this as an example of a
product table that you would use to search for products, then you're
misunderstanding the example being given.

[1] I'd have a cart table with one line per cart, and then a separate
cart_contents table with one line per product and a cart_id column which
links it to the cart table. That also allows a separate cart_address
table which can have multiple addresses per cart (eg, billing address,
delivery address).

Mark
--
http://mark.goodge.co.uk

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