Database Schema: Incorrect Unique Indexes

[SchumacherFM]

Regarding my database inspections for migrating Mage1->2 I've found this thing:

The unique key which conflicts is in table cataloginventory_stock_item with the name

UNQ_CATALOGINVENTORY_STOCK_ITEM_PRODUCT_ID_WEBSITE_ID for (product_id,website_id).

IMHO: This does not make sense because of the column stock_id. The unique key must be on (product_id,stock_id). This newly introduced column website_id is totally wrong. In table cataloginventory_stock you also have added the column website_id which doesn't make sense.
You can still have the same stock_id associated to multiple website_ids or vice versa; so a third table would be necessary for assigning stock_ids to website_ids.
The current solution in table cataloginventory_stock looks like that for each website you must create its own stock_id ... 👎

If I'm absolutely wrong with my IMHO a short explanation would be great on what kind of "multiwarehouse" feature you are working on!

[IvanChepurnyi]

I totally support your point concerning website_id in stock tables. Even if it is a part of multiwarehouse feature, website_id should not be in any of the following tables, it is easier to make a relation between website and stock via configuration.

Let's imagine we have a company that sells to US/CA market and EU market, they have a website for each country. But there is only 2 warehouses: EU warehouse in Germany and US/CA warehouse in US. Hope it will clarify the idea of separation stock scope from table level to a configuration, that is IMO much more flexible and has less performance/data size penalty.

[kokoc]

Thank you for reporting the issue. This issue will be fixed in context of other inventory improvements.
Internal reference: MAGETWO-33564

[ln8711]

From I see, the website_id is now 1 for all created product, right?

[maderlock]

Given that the default website = 0 for stock id =1 in table cataloginventory_stock, this suggests that all website IDs should be 0.

@hoanglan87 believes that all website_ids should be 1, and the code in module-catalog-inventory/Model/ResourceModel/Indexer/Stock/DefaultStock.php equates website_id to stock_id so that seems to make it always 1.

If I set all website_ids to 0 in cataloginventory_stock_item and reindex then I get a mixture of entries for website_id 0 and 1. This may explain some anomalous results with configurable products going in and out of stock.

Please could there be a definitive statement on this "functionality".