Product variants

DB data (saved variants)

id	variant
1	Green, 128GB
2	Green, 256GB
3	Red, 128GB
4	Red, 256GB

CASE1: add variants Memory 2GB

All products have id, so all need to be update.

id	variant
1	Green, 128 GB, 2GB
2	Green, 256 GB, 2GB
3	Red, 128 GB, 2GB
4	Red, 256 GB, 2GB

CASE2: add variants storage 512GB

Products with id = 0 are new and need to be created, others updated.

id	variant
1	Green, 128GB, 2GB
2	Green, 256GB, 2GB
0	Green, 512GB, 2GB
3	Red, 128GB, 2GB
4	Red, 256GB, 2GB
0	Red, 512GB, 2GB

CASE3: add variants Memory 2GB, 4GB

Products with id = 0 are new and need to be created, others updated.

id	variant
1	Green, 128GB, 2GB
2	Green, 256GB, 2GB
3	Red, 128GB, 2GB
4	Red, 256GB, 2GB

0 | Green, 128GB, 4GB 0 | Green, 256GB, 4GB 0 | Red, 128GB, 4GB 0 | Red, 256GB, 4GB