sequelize 是Node.js中應用最廣泛的orm開源庫，github：https://github.com/sequelize/sequelize。
中文文檔：https://github.com/demopark/sequelize-docs-Zh-CN
Sequelize 是一個基于 promise 的 Node.js ORM, 目前支持 Postgres, MySQL, SQLite 和 Microsoft SQL Server. 它具有強大的事務支持, 關聯關系, 讀取和復制等功能.
按照官方文檔做，總是覺得不對勁，做的非常累，總有勞動力沒有解放的感覺。后來發現這個庫還有兩個關鍵的配套工具sequelize-cli，和sequelize-auto。
sequelize-cli用來通過命令產生對應的代碼模型和數據庫遷移。
sequelize-auto 用來通過已有的數據庫結構生成代碼模型和數據庫遷移。
常用命令

sequelize-auto -h localhost -d login_demo -u root -x root -p 3306 -t user

Options:
  -h, --host        IP/Hostname for the database.   [required]
  -d, --database    Database name.                  [required]
  -u, --user        Username for database.
  -x, --pass        Password for database.
  -p, --port        Port number for database.
  -c, --config      JSON file for Sequelize's constructor "options" flag object as defined here: https://sequelize.readthedocs.org/en/latest/api/sequelize/
  -o, --output      What directory to place the models.
  -e, --dialect     The dialect/engine that you're using: postgres, mysql, sqlite
  -a, --additional  Path to a json file containing model definitions (for all tables) which are to be defined within a model's configuration parameter. For more info: https://sequelize.readthedocs.org/en/latest/docs/models-definition/#configuration
  -t, --tables      Comma-separated names of tables to import
  -T, --skip-tables Comma-separated names of tables to skip
  -C, --camel       Use camel case to name models and fields
  -n, --no-write    Prevent writing the models to disk.
  -s, --schema      Database schema from which to retrieve tables

node_modules/.bin/sequelize model:generate --name User --attributes firstName:string,lastName:string,email:string
node_modules/.bin/sequelize db:migrate
node_modules/.bin/sequelize db:migrate:undo

經過測試 這兩命令不能看做互逆操作。如何處理自己看著辦吧。