Drizzle Core Schema Patterns

Comprehensive schema definition guide for Drizzle ORM, applicable across all supported databases (PostgreSQL, MySQL, SQLite, MSSQL). Contains 9 rules across 3 categories focused on building type-safe, well-structured database schemas.

When to Apply

Reference these guidelines when:

• •Defining new database tables with Drizzle ORM
• •Setting up primary keys (single or composite)
• •Creating foreign key relationships between tables
• •Adding indexes for query performance
• •Implementing constraints (unique, check, not null)
• •Configuring default values for columns
• •Setting up Drizzle relations for type-safe queries

Rule Categories by Priority

Quick Reference

1. Schema Definition (CRITICAL)

• •schema-table-definition - Define tables with proper structure and exports
• •schema-column-modifiers - Use .notNull(), .default(), .$type<>() correctly
• •schema-primary-keys - Single and composite primary key patterns

2. Constraints (HIGH)

• •schema-foreign-keys - Foreign key relationships and self-references
• •schema-unique-constraints - Single and composite unique constraints
• •schema-check-constraints - Data validation with check constraints
• •schema-default-values - Static, SQL expression, and function defaults

3. Performance & Relations (MEDIUM-HIGH)

• •schema-indexes - Index creation for query optimization
• •schema-relations - Drizzle relations for type-safe joins

How to Use

Read individual rule files for detailed explanations and code examples:

rules/schema-table-definition.md
rules/schema-primary-keys.md
rules/schema-foreign-keys.md

Each rule file contains:

• •Brief explanation of why it matters
• •Incorrect code example with explanation
• •Correct code example with explanation
• •Additional context and variations

Full Compiled Document

For the complete guide with all rules expanded: AGENTS.md