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Database Schema With ER Model
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Database Schema With ER Model

MediumSQL · PostgreSQL

Problem

Create a database schema for a small e-commerce.

Use a normalized design for customers, products, and orders, including primary keys, foreign keys, suitable data types, and order totals. Then provide a query that validates the design by summarizing customer purchasing activity.

Output

  1. One row per customer, including customers without orders
  2. Columns: customer_name, order_count, distinct_products, total_spent, and last_order_date
  3. Include all customers, treat missing totals as zero, and sort by total_spent descending, then customer_id ascending

Schema

customers
ColumnTypeDescription
customer_idPKINTUnique customer identifier
customer_nameVARCHAR(100)Customer display name
emailVARCHAR(255)Customer email address
products
ColumnTypeDescription
product_idPKINTUnique product identifier
product_nameVARCHAR(150)Product name
categoryVARCHAR(80)Product category
current_priceNUMERIC(10,2)Current catalog price
orders
ColumnTypeDescription
order_idPKINTUnique order identifier
customer_idINTCustomer who placed the order
product_idINTProduct included in the order
quantityINTNumber of units ordered
unit_priceNUMERIC(10,2)Price per unit at order time
ordered_atDATEDate the order was placed
Tablescustomersproductsorders
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