Database Schema Design

Instructions

1. •

   Schema Planning

   • •Identify entities and attributes
   • •Define primary keys
   • •Normalize data (avoid redundancy)
   • •Choose appropriate data types
2. •

   Table Design

   • •Use meaningful table and column names
   • •Apply constraints (NOT NULL, UNIQUE, CHECK)
   • •Define indexes for frequently queried columns
   • •Maintain consistency in naming conventions
3. •

   Relationships

   • •One-to-One (1:1)
   • •One-to-Many (1:N)
   • •Many-to-Many (M:N) using junction tables
   • •Enforce referential integrity using foreign keys
4. •

   Migrations

   • •Version-controlled schema changes
   • •Use up/down migrations
   • •Never edit old migrations in production
   • •Ensure migrations are reversible
5. •

   Scalability Considerations

   • •Avoid over-normalization
   • •Plan for future growth
   • •Use indexing wisely
   • •Consider read/write patterns

Best Practices

• •Use snake_case for table and column names
• •Always define primary keys
• •Prefer UUIDs for distributed systems
• •Add timestamps (created_at, updated_at)
• •Keep migrations small and focused
• •Document schema decisions

Example Schema (SQL)

CREATE TABLE users (
  id SERIAL PRIMARY KEY,
  email VARCHAR(255) UNIQUE NOT NULL,
  password_hash TEXT NOT NULL,
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);