RESULTS OF NORMALIZATION
One table turned into four
players
purchases
items
item_slots
player_id PK
nickname
level
region
purchase_id Primary Key
player_id FK
item_id FK
price_paid
bought_at
item_id Primary Key
name price
type
item_id FK
slot
PK (item_id, slot)
Item Price — All in One Place
An item can last without being purchased
Deleting a purchase is safe
Change it once; no duplicate prices in purchases
You can add it to the catalog in advance
The object and the player remain in place
The cost of normalization is a JOIN of three tables instead of reading a single row.