I'm currently making an ER diagram for my product model. But I'm confused that the DISCOUNT needs an entity to connect with the product module or it can just be an attributes of the product? my current product module: the

PRODUCT

PRODUCT_ID(PK)

PRODUCT_NAME

PRODUCT_PRICE

PRODUCT_TYPE

PRODUCT_COLOUR

PRODUCT_SIZE

STOCK_UNIT (FK)

this is the entity i try to make for DISCOUNT

PRODUCT_ID (PK,FK)

ADMIN_ID(FK)

DISCOUNT_DATE

DISCOUNTED_PRICE

In my scenario, some of the specific product prices can be discounted with value/ per centage. But I am confused that do i need to put the discount value/percentage as an attribute or an entity in the product module because there are only some products that have the discounted price.

I hope that my explanation is clear enough ><

CodePudding user response：

Based on question and comments, I suggest:

Discount Table
--------------
DISCOUNT_ID (PrimaryKey)
PRODUCT_ID (ForeignKey)
IsPERCENT (Bool)
DISCOUNT (Float|Double)
FROM_DATE (DateTime)
TILL_DATE (DateTime)

IsPercent should be True if discount is to calculated using Percentage.

Discount should be value (treated as percent or Currency depending on IsPercent)

Also in your program, validate that Discount value doesn't go above 100 if IsPercent is TRUE