It would be nice to implement a way to suggest additional items when an Item is added to the cart. For the database that I built for my own website I created a cross-reference table that links other Items' Variations' to the selected Variation via a ClassID number, excluding the current Item's Category, and returns matching Variations from them.
When a Twin Mattress is selected, the cross reference table finds all other matching Twin Items including Twin Box Springs, Twin Protectors, Twin Sheets, and Twin Frames. Here is a simplified example of what I have:
Categories:
| Cat_ID | Cat_Name |
| 1 | Mattresses |
| 2 | Foundations |
| 3 | Frames |
| 4 | Sheets |
| etcetera... | |
| Class_ID | Class_Name | |
| 1 | Twin Size | |
| 2 | Full Size | |
| 3 | Queen Size | |
| 4 | King Size | |
| etcetera... | | |
Cross Reference
| Class Cross ID | Class_Cat | Class_Cross_Ref |
| 1 | 1 | 2,3,4 |
| 2 | 1 | 2,3,4 |
| 3 | 1 | 2,3,4 |
| 4 | 1 | 2,3,4 |
| 5 | 2 | 3 |
| 6 | 2 | 3 |
| 7 | 2 | 3 |
| 8 | 2 | 3 |
| 9 | 3 | 2 |
| 10 | 3 | 2 |
| 11 | 3 | 2 |
| 12 | 3 | 2 |
| etcetera... | | |
An Item in Category 1 (Mattress) has a Variation (Full) with a ClassID of 2, which finds additional Items and Variations with the same ClassID. So a Full Size Mattress (ClassID 2) finds and offers matching Full Size Foundations, Frames, Sheets, etc.
Square already has its Category Table and Square could use the Data from Option Sets as Class IDs, so all that needs to be added is a CrossReference Field in that Option Set Data, where you can link each Option Set's datarow to another Option Set's datarow(s).
This would only work for Item Variations created using the Option... er, option "to create variations in bulk" since that links Variations together across multiple Items. Feel free to ask for clarification, I tried to be as brief as possible without loosing specificity.
