Keeping stock for certain sets of combinations

[FrankvanCaspel]

We've developed a webshop for a company which is selling snow chains. Currently, the catalogue is set up as follows:

- Every type of snow chain is a product. For example: the 'Pewag Nordic Star' is a product in the catalogue.

- Every product has tons of combinations of attributes (width, diameter, etc.). The Nordic Star has over 150 combinations of these sizes.

- Stock is kept for every separate combination/size. For example: if size 175-70/13 is sold through the webshop, only that size gets its quantity reduced by one.

However, we've only recently realized that the tons of sizes we've incorporated in the shop do not reflect different actual snow chains, but that they correspond with the sizes of wheels on which the particular type of snow chain can be fitted. So actually, the Nordic Star has only a limited (around 5-8) actual different sizes, which each fit a range of the sizes in the shop. So keeping stock for each size is useless.

Is there any way in which we can fix this easily? For example:
- Making sets of combinations for which stock is kept. These sets would correspond to the different sizes of snow chain.
- Making 'subproducts' to which we assign certain sets of combinations.

What we do not want is multiple sizes of a single type of snow chain showing up in the shop. The main difficulty is that customers want to search using their wheel size, and not 'chain subtype'.

And if there is no easy fix, how could we design this from the ground up? Is there a way of having products which have different sizes, and in which each of these sizes has a set of combinations of attributes? Example:

Product: Nordic Star

Sizes: A, B, C, D, E, F

Size A fits wheel sizes 175-70/13, 185-70/13, etc...
Size B ...
...

Where in the shop it only shows the product, not the different sizes, and stock is being kept per size.

[tomerg3]

It's very hard understand exactly what you need, can you perhaps give a live example or some screen shot of how you want it to work.

[FrankvanCaspel]

Hmm, sorry about being fuzzy. I'll try and explain using a screenshot:

!http://img849.imageshack.us/img849/7227/screencombinations.png!

What you see here is the 'Combinations'-tab for one of the snow chains - the Nordic Star. As you can see, every combination has three attributes: diameter, proportion, and width (they're in Dutch). At the bottom of the screenshot, you can see the first two of over 150 combinations for this single chain.

Customers come to the webshop and enter their car tire measurements (which correspond to the attributes in the combinations) and are presented with all chains which have a combination which matches their tire.

Every combination has its own inventory (the semi-final column at the bottom of the screenshot shows this, 'aantal' is Dutch for 'Quantity'). However, this is where the problem starts: the chains only come in about 8 sizes, each size fitting a range of tires. So keeping stock for each of the combinations is useless. What is needed is to keep an inventory having quantities of the different sizes of chains, or, relating to the current situation: keeping an inventory per set of combinations, not per combination.

Say, for example, that one size of chain fits the two combinations you see at the bottom of the screenshot. In that case, if one of the combinations gets sold, the other one has to have its quantity adjusted as well. The quantities of certain sets of combinations have to be linked.

We've come up with the idea to add a fourth attribute to our combinations, corresponding to the size of chain to which it 'belongs'. And our 'chief programming officer' would then provide a mechanism whereby any combination which has the same size as a combination that is sold, also gets its quantity reduced by one. Does this seem like a proper solution?

[tomerg3]

I have a module that may do what you need (there's a backend demo page where you can try it)

The module changes the way combinations are handled in order to allow the use of unlimited attributes per product (by default, PS can only handle about 1,000-3,000 combinations).

You basically enter in each combination 1 or more attributes from the same group, and assign the a stock / price impact.

If you don't have a price impact for them you will have 4 attribute groups in total, 3 with all the attributes from each of the 3 groups, and a 4th group (the default one) with 1 attribute value from each group, which will be used to indicate the default select when the customer enters the product page.

Check out http://www.prestashop.com/forums/viewthread/47363/

[FrankvanCaspel]

Thanks, we'll look in to it.