Database Schema Designer

Input

Data Requirements

E-commerce platform: users register and place multiple orders. Each order has line items linked to products. Products belong to one or more categories and support variants (size, color) with independent SKUs and stock. Users leave verified reviews with a 1-5 star rating and optional photos. Track inventory levels per variant and order status history.

Database Engine

PostgreSQL

Schema Style

Normalized (3NF)

Output Format

SQL DDL (CREATE TABLE)

Relationship Complexity

Many-to-many (Junction tables)

Output (excerpt)

CREATE TABLE users (id BIGSERIAL PRIMARY KEY, email CITEXT UNIQUE NOT NULL, created_at TIMESTAMPTZ DEFAULT now());
CREATE TABLE products (id BIGSERIAL PRIMARY KEY, name TEXT NOT NULL, base_price NUMERIC(10,2));
CREATE TABLE product_variants (id BIGSERIAL PRIMARY KEY, product_id BIGINT REFERENCES products(id), sku TEXT UNIQUE, size TEXT, color TEXT, stock INT DEFAULT 0);
CREATE TABLE product_categories (product_id BIGINT, category_id BIGINT, PRIMARY KEY (product_id, category_id)); -- junction table for many-to-many.

Input

Data Requirements

Marketing analytics warehouse for email campaigns. We need to report opens, clicks, unsubscribes, and conversions by campaign, subscriber segment, send date, and device. Fact table records each engagement event; dimensions cover campaign, subscriber, date, and channel for fast aggregation in BI dashboards.

Database Engine

PostgreSQL

Schema Style

Star Schema (Analytics / DWH)

Output Format

Text Diagram (ASCII ERD)

Relationship Complexity

Simple (1:1, 1:N)

Output (excerpt)

fact_engagement (event_id, date_key FK, campaign_key FK, subscriber_key FK, channel_key FK, event_type, revenue)
  |-- dim_date (date_key, full_date, week, month, quarter, year)
  |-- dim_campaign (campaign_key, name, subject_line, send_type)
  |-- dim_subscriber (subscriber_key, segment, signup_source, country)
  |-- dim_channel (channel_key, device, client, os)
Grain: one row per subscriber engagement event. Optimized for GROUP BY rollups across any dimension.

Input

Data Requirements

Lightweight invoicing app for a solo freelancer. Track clients, projects per client, time entries logged against projects, and invoices that bundle billable time entries. Each invoice has a status (draft, sent, paid, overdue) and line items. Need simple one-to-many relationships and local storage on a laptop.

Database Engine

SQLite

Schema Style

Normalized (3NF)

Output Format

Migration Script (Versioned)

Relationship Complexity

Simple (1:1, 1:N)

Output (excerpt)

-- 0001_init.sql
CREATE TABLE clients (id INTEGER PRIMARY KEY, name TEXT NOT NULL, email TEXT);
CREATE TABLE projects (id INTEGER PRIMARY KEY, client_id INTEGER REFERENCES clients(id), name TEXT, hourly_rate REAL);
CREATE TABLE time_entries (id INTEGER PRIMARY KEY, project_id INTEGER REFERENCES projects(id), minutes INTEGER, logged_on DATE, billed INTEGER DEFAULT 0);
CREATE TABLE invoices (id INTEGER PRIMARY KEY, client_id INTEGER REFERENCES clients(id), status TEXT DEFAULT 'draft', total REAL, issued_on DATE);