Sequelize v7 — Claude Skill

Key Differences from Sequelize v6

• Package renamed: sequelize → @sequelize/core
• Dialects are separate packages (e.g., @sequelize/postgres, @sequelize/sqlite3)
• Decorator-based model definitions (recommended over Model.init())
• Constructor only accepts a single options object (no URL string as first arg)
• dialectOptions removed — settings go in top-level options
• CLS transactions enabled by default (no manual setup needed)
• Default association names are now camelCase (userId not UserId)
• sequelize.transaction() only creates managed transactions; use sequelize.startUnmanagedTransaction() for unmanaged
• JSON null vs SQL NULL distinction: inserting null into JSON stores JSON 'null', not SQL NULL
• Minimum: Node >= 18, TypeScript >= 5.0

Skill Files

Quick Reference — Common Patterns

Minimal Model (TypeScript + Decorators)

import { Model, InferAttributes, InferCreationAttributes, CreationOptional, DataTypes } from '@sequelize/core';
import { Attribute, PrimaryKey, AutoIncrement, NotNull } from '@sequelize/core/decorators-legacy';

export class User extends Model<InferAttributes<User>, InferCreationAttributes<User>> {
  @Attribute(DataTypes.INTEGER)
  @PrimaryKey
  @AutoIncrement
  declare id: CreationOptional<number>;

  @Attribute(DataTypes.STRING)
  @NotNull
  declare name: string;

  @Attribute(DataTypes.STRING)
  declare email: string | null;

  declare createdAt: CreationOptional<Date>;
  declare updatedAt: CreationOptional<Date>;
}

Initialize Sequelize

import { Sequelize } from '@sequelize/core';
import { PostgresDialect } from '@sequelize/postgres';

const sequelize = new Sequelize({
  dialect: PostgresDialect,
  host: 'localhost',
  port: 5432,
  database: 'mydb',
  user: 'user',
  password: 'pass',
  models: [User],
});

Basic CRUD

// Create
const user = await User.create({ name: 'Alice' });

// Read
const users = await User.findAll({ where: { name: 'Alice' } });
const one = await User.findByPk(1);

// Update
await user.update({ name: 'Bob' });
await User.update({ name: 'Bob' }, { where: { id: 1 } });

// Delete
await user.destroy();
await User.destroy({ where: { id: 1 } });

Association with Eager Loading

const posts = await Post.findAll({
  include: ['comments'],
  where: { authorId: 1 },
});

Managed Transaction

const result = await sequelize.transaction(async () => {
  const user = await User.create({ name: 'Alice' });
  await Profile.create({ userId: user.id, bio: 'Hello' });
  return user;
});