TypeScript

import { Model, Optional } from 'sequelize';

// We don't recommend doing this. Read on for the new way of declaring Model typings.

type UserAttributes = {
  id: number,
  name: string,
  // other attributes...
};

// we're telling the Model that 'id' is optional
// when creating an instance of the model (such as using Model.create()).
type UserCreationAttributes = Optional<UserAttributes, 'id'>;

class User extends Model<UserAttributes, UserCreationAttributes> {
  declare id: number;
  declare name: string;
  // other attributes...
}

import { Model, InferAttributes, InferCreationAttributes, CreationOptional } from 'sequelize';

// order of InferAttributes & InferCreationAttributes is important.
class User extends Model<InferAttributes<User>, InferCreationAttributes<User>> {
  // 'CreationOptional' is a special type that marks the field as optional
  // when creating an instance of the model (such as using Model.create()).
  declare id: CreationOptional<number>;
  declare name: string;
  // other attributes...
}

class User extends Model<InferAttributes<User>, InferCreationAttributes<User>> {
  declare firstName: string;

  // 不需要在 lastName 上使用 CreationOptional
  // 因为可为 null 的属性在 User.create() 中始终是可选的
  declare lastName: string | null;
}

// ...

await User.create({
  firstName: 'Zoé',
  // 省略姓氏, 但这仍然有效！
});

import {
  Association, DataTypes, HasManyAddAssociationMixin, HasManyCountAssociationsMixin,
  HasManyCreateAssociationMixin, HasManyGetAssociationsMixin, HasManyHasAssociationMixin,
  HasManySetAssociationsMixin, HasManyAddAssociationsMixin, HasManyHasAssociationsMixin,
  HasManyRemoveAssociationMixin, HasManyRemoveAssociationsMixin, Model, ModelDefined, Optional,
  Sequelize, InferAttributes, InferCreationAttributes, CreationOptional, NonAttribute
} from 'sequelize';

const sequelize = new Sequelize('mysql://root:asd123@localhost:3306/mydb');

// 'projects' is excluded as it's not an attribute, it's an association.
class User extends Model<InferAttributes<User, { omit: 'projects' }>, InferCreationAttributes<User, { omit: 'projects' }>> {
  // id can be undefined during creation when using `autoIncrement`
  declare id: CreationOptional<number>;
  declare name: string;
  declare preferredName: string | null; // for nullable fields

  // timestamps!
  // createdAt can be undefined during creation
  declare createdAt: CreationOptional<Date>;
  // updatedAt can be undefined during creation
  declare updatedAt: CreationOptional<Date>;

  // Since TS cannot determine model association at compile time
  // we have to declare them here purely virtually
  // these will not exist until `Model.init` was called.
  declare getProjects: HasManyGetAssociationsMixin<Project>; // Note the null assertions!
  declare addProject: HasManyAddAssociationMixin<Project, number>;
  declare addProjects: HasManyAddAssociationsMixin<Project, number>;
  declare setProjects: HasManySetAssociationsMixin<Project, number>;
  declare removeProject: HasManyRemoveAssociationMixin<Project, number>;
  declare removeProjects: HasManyRemoveAssociationsMixin<Project, number>;
  declare hasProject: HasManyHasAssociationMixin<Project, number>;
  declare hasProjects: HasManyHasAssociationsMixin<Project, number>;
  declare countProjects: HasManyCountAssociationsMixin;
  declare createProject: HasManyCreateAssociationMixin<Project, 'ownerId'>;

  // You can also pre-declare possible inclusions, these will only be populated if you
  // actively include a relation.
  declare projects?: NonAttribute<Project[]>; // Note this is optional since it's only populated when explicitly requested in code

  // getters that are not attributes should be tagged using NonAttribute
  // to remove them from the model's Attribute Typings.
  get fullName(): NonAttribute<string> {
    return this.name;
  }

  declare static associations: {
    projects: Association<User, Project>;
  };
}

class Project extends Model<
  InferAttributes<Project>,
  InferCreationAttributes<Project>
> {
  // id can be undefined during creation when using `autoIncrement`
  declare id: CreationOptional<number>;
  declare ownerId: number;
  declare name: string;

  // `owner` is an eagerly-loaded association.
  // We tag it as `NonAttribute`
  declare owner?: NonAttribute<User>;

  // createdAt can be undefined during creation
  declare createdAt: CreationOptional<Date>;
  // updatedAt can be undefined during creation
  declare updatedAt: CreationOptional<Date>;
}

class Address extends Model<
  InferAttributes<Address>,
  InferCreationAttributes<Address>
> {
  declare userId: number;
  declare address: string;

  // createdAt can be undefined during creation
  declare createdAt: CreationOptional<Date>;
  // updatedAt can be undefined during creation
  declare updatedAt: CreationOptional<Date>;
}

Project.init(
  {
    id: {
      type: DataTypes.INTEGER.UNSIGNED,
      autoIncrement: true,
      primaryKey: true
    },
    ownerId: {
      type: DataTypes.INTEGER.UNSIGNED,
      allowNull: false
    },
    name: {
      type: new DataTypes.STRING(128),
      allowNull: false
    },
    createdAt: DataTypes.DATE,
    updatedAt: DataTypes.DATE,
  },
  {
    sequelize,
    tableName: 'projects'
  }
);

User.init(
  {
    id: {
      type: DataTypes.INTEGER.UNSIGNED,
      autoIncrement: true,
      primaryKey: true
    },
    name: {
      type: new DataTypes.STRING(128),
      allowNull: false
    },
    preferredName: {
      type: new DataTypes.STRING(128),
      allowNull: true
    },
    createdAt: DataTypes.DATE,
    updatedAt: DataTypes.DATE,
  },
  {
    tableName: 'users',
    sequelize // passing the `sequelize` instance is required
  }
);

Address.init(
  {
    userId: {
      type: DataTypes.INTEGER.UNSIGNED
    },
    address: {
      type: new DataTypes.STRING(128),
      allowNull: false
    },
    createdAt: DataTypes.DATE,
    updatedAt: DataTypes.DATE,
  },
  {
    tableName: 'address',
    sequelize // passing the `sequelize` instance is required
  }
);

// You can also define modules in a functional way
interface NoteAttributes {
  id: number;
  title: string;
  content: string;
}

// You can also set multiple attributes optional at once
type NoteCreationAttributes = Optional<NoteAttributes, 'id' | 'title'>;

// And with a functional approach defining a module looks like this
const Note: ModelDefined<
  NoteAttributes,
  NoteCreationAttributes
> = sequelize.define(
  'Note',
  {
    id: {
      type: DataTypes.INTEGER.UNSIGNED,
      autoIncrement: true,
      primaryKey: true
    },
    title: {
      type: new DataTypes.STRING(64),
      defaultValue: 'Unnamed Note'
    },
    content: {
      type: new DataTypes.STRING(4096),
      allowNull: false
    }
  },
  {
    tableName: 'notes'
  }
);

// Here we associate which actually populates out pre-declared `association` static and other methods.
User.hasMany(Project, {
  sourceKey: 'id',
  foreignKey: 'ownerId',
  as: 'projects' // this determines the name in `associations`!
});

Address.belongsTo(User, { targetKey: 'id' });
User.hasOne(Address, { sourceKey: 'id' });

async function doStuffWithUser() {
  const newUser = await User.create({
    name: 'Johnny',
    preferredName: 'John',
  });
  console.log(newUser.id, newUser.name, newUser.preferredName);

  const project = await newUser.createProject({
    name: 'first!'
  });

  const ourUser = await User.findByPk(1, {
    include: [User.associations.projects],
    rejectOnEmpty: true // Specifying true here removes `null` from the return type!
  });

  // Note the `!` null assertion since TS can't know if we included
  // the model or not
  console.log(ourUser.projects![0].name);
}