Dialect needs to be explicitly supplied as of v4.0.0

使用sequelize，初始化时报错 Dialect needs to be explicitly supplied as of v4.0.0

C:\Users\11783\Desktop\tocity-service\node_modules\sequelize\lib\sequelize.js:281
      throw new Error('Dialect needs to be explicitly supplied as of v4.0.0');
      ^

Error: Dialect needs to be explicitly supplied as of v4.0.0
    at new Sequelize (C:\Users\11783\Desktop\tocity-service\node_modules\sequelize\lib\sequelize.js:281:13)
    at Object.<anonymous> (C:\Users\11783\Desktop\tocity-service\app.js:11:19)
    at Module._compile (internal/modules/cjs/loader.js:959:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:995:10)
    at Module.load (internal/modules/cjs/loader.js:815:32)

解决方案

const sequelize = new Sequelize('database', 'username', 'password', {
  host: 'localhost',
  dialect: /* 选择 'mysql' | 'mariadb' | 'postgres' | 'mssql' 其一 */
});

之前没有使用dialect指明具体数据库所以出错