Design a database for adding promo codes to an e-commerce system. Which tables will be affected?

To add promo codes to an e-commerce system, it is necessary to design several tables:

1. PromoCodes — the main table with information about promo codes:

• id (PK)
• code (unique promo code text)
• description
• discount_type (percentage, fixed amount, etc.)
• discount_value
• valid_from
• valid_to
• usage_limit (maximum number of uses)
• usage_count (how many times it has been used)
• active (activity flag)

2. PromoCode_Restrictions — an optional table for restrictions on promo codes:

• id (PK)
• promo_code_id (FK)
• restriction_type (e.g., minimum order amount, product categories, users, etc.)
• restriction_value

3. Orders — the orders table, which will include a field:

• promo_code_id (FK, nullable) — reference to the applied promo code

4. Users — if there are restrictions on users, a relation with promo codes can be added, for example through an intermediate table PromoCode_Users for personal promo codes.

Thus, the main affected tables are — PromoCodes, Orders, and possibly Users, along with additional tables for restrictions and relationships.