Terminal.skills
Skills/sequelize
>

sequelize

You are an expert in Sequelize, the promise-based ORM for Node.js supporting PostgreSQL, MySQL, MariaDB, SQLite, and MS SQL. You help developers define models, build queries, manage migrations, handle associations, use transactions, and configure connection pooling — providing a mature, battle-tested data access layer for production Node.js applications.

#orm#javascript#database#sql#postgres#mysql#migrations#node
terminal-skillsv1.0.0
Works with:claude-codeopenai-codexgemini-clicursor
Source

Usage

$
✓ Installed sequelize v1.0.0

Getting Started

  1. Install the skill using the command above
  2. Open your AI coding agent (Claude Code, Codex, Gemini CLI, or Cursor)
  3. Reference the skill in your prompt
  4. The AI will use the skill's capabilities automatically

Example Prompts

  • "Review the open pull requests and summarize what needs attention"
  • "Generate a changelog from the last 20 commits on the main branch"

Information

Version
1.0.0
Author
terminal-skills
Category
Backend Development
License
Apache-2.0

Documentation

You are an expert in Sequelize, the promise-based ORM for Node.js supporting PostgreSQL, MySQL, MariaDB, SQLite, and MS SQL. You help developers define models, build queries, manage migrations, handle associations, use transactions, and configure connection pooling — providing a mature, battle-tested data access layer for production Node.js applications.

Core Capabilities

Model Definition

typescript
import { Model, DataTypes, Sequelize, InferAttributes, InferCreationAttributes } from "sequelize";

const sequelize = new Sequelize(process.env.DATABASE_URL!, {
  dialect: "postgres",
  pool: { max: 20, min: 5, acquire: 30000, idle: 10000 },
  logging: process.env.NODE_ENV === "development" ? console.log : false,
});

class User extends Model<InferAttributes<User>, InferCreationAttributes<User>> {
  declare id: number;
  declare name: string;
  declare email: string;
  declare role: "user" | "admin";
  declare createdAt: Date;
  declare updatedAt: Date;
}

User.init({
  id: { type: DataTypes.INTEGER, autoIncrement: true, primaryKey: true },
  name: { type: DataTypes.STRING(100), allowNull: false, validate: { len: [2, 100] } },
  email: { type: DataTypes.STRING, allowNull: false, unique: true, validate: { isEmail: true } },
  role: { type: DataTypes.ENUM("user", "admin"), defaultValue: "user" },
}, {
  sequelize, tableName: "users", timestamps: true,
  hooks: {
    beforeCreate: (user) => { user.email = user.email.toLowerCase(); },
  },
});

class Post extends Model<InferAttributes<Post>, InferCreationAttributes<Post>> {
  declare id: number;
  declare title: string;
  declare body: string;
  declare published: boolean;
  declare authorId: number;
}

Post.init({
  id: { type: DataTypes.INTEGER, autoIncrement: true, primaryKey: true },
  title: { type: DataTypes.STRING, allowNull: false },
  body: { type: DataTypes.TEXT, allowNull: false },
  published: { type: DataTypes.BOOLEAN, defaultValue: false },
  authorId: { type: DataTypes.INTEGER, allowNull: false },
}, { sequelize, tableName: "posts" });

// Associations
User.hasMany(Post, { foreignKey: "authorId", as: "posts" });
Post.belongsTo(User, { foreignKey: "authorId", as: "author" });

Queries

typescript
// Find with eager loading
const users = await User.findAll({
  where: { role: "user" },
  include: [{ model: Post, as: "posts", where: { published: true }, required: false }],
  order: [["createdAt", "DESC"]],
  limit: 10, offset: 20,
});

// Raw query for complex operations
const [results] = await sequelize.query(`
  SELECT u.name, COUNT(p.id) as post_count
  FROM users u LEFT JOIN posts p ON u.id = p."authorId"
  GROUP BY u.id ORDER BY post_count DESC LIMIT 10
`);

// Transaction
await sequelize.transaction(async (t) => {
  const user = await User.create({ name: "Alice", email: "alice@example.com" }, { transaction: t });
  await Post.create({ title: "First Post", body: "Hello", authorId: user.id }, { transaction: t });
});

// Bulk operations
await User.bulkCreate(usersData, { validate: true, updateOnDuplicate: ["name"] });

Installation

bash
npm install sequelize
npm install pg pg-hstore                  # PostgreSQL
npm install sequelize-cli                 # Migrations CLI
npx sequelize init                        # Generate config/migrations/models dirs

Best Practices

  1. Migrations — Use sequelize-cli for migrations; never use sync() in production
  2. TypeScript — Use InferAttributes / InferCreationAttributes for full type inference
  3. Scopes — Define reusable query scopes: User.scope('active').findAll() for common filters
  4. Transactions — Wrap related operations in transactions; use CLS for automatic transaction propagation
  5. Paranoid mode — Enable paranoid: true for soft deletes; adds deletedAt column automatically
  6. Eager loading — Use include for joins; set required: false for LEFT JOIN behavior
  7. Hooks — Use beforeCreate, afterUpdate for business logic; keep models self-validating
  8. Connection pool — Set max to match expected concurrency; idle to release unused connections