sequelize

Sequelize Rules

Model Definition

• Use sequelize.define() or class-based models extending Model
• Define attributes with proper data types and validation rules
• Use underscored naming convention for database columns
• Implement proper indexes for performance-critical fields
• Define timestamps (createdAt, updatedAt) explicitly

Associations

• Define associations in model files or separate association files
• Use hasMany, hasOne, belongsTo, belongsToMany appropriately
• Always define foreign key constraints and onDelete/onUpdate actions
• Use include option for eager loading related data
• Implement through models for many-to-many relationships

Migrations

• Create migrations for all database schema changes
• Use descriptive migration filenames with timestamps
• Implement both up and down methods for rollback capability
• Add proper indexes in migrations, not just model definitions
• Use transactions in migrations for atomicity

Querying

• Use findOne, findAll, findByPk for basic queries
• Implement proper where clauses with operators (Op.eq, Op.like, etc.)
• Use attributes option to select specific fields
• Implement pagination with limit and offset
• Use raw queries sparingly and with proper parameter binding

Validation & Hooks

• Implement model-level validations for data integrity
• Use beforeSave, afterSave hooks for business logic
• Implement custom validation functions when needed
• Use paranoid models for soft deletes when appropriate
• Add proper error handling for validation failures

Performance

• Use connection pooling configuration
• Implement proper eager loading to avoid N+1 queries
• Use database transactions for complex operations
• Add database indexes for frequently queried fields
• Use read replicas for read-heavy operations