Am I required to handwrite the model definitions for Sequelize even if I'm working off of an existing database.
If it's not required, then how does one go about using Sequelize with an existing database?
I've already defined the database's schema in Doctrine, so I'd rather not have to write another set of model definitions again.
The easiest and most flexible way to do this is to declare multiple databases in our config. js and then loop over these databases in the file handling our database connections (in my case this is the index. js of my models folder).
To import Sequelize models, you need to export the model as a module first. The code above creates a new instance of the Sequelize class to connect to your database. The sequelize instance needs to be passed into the user. js model file when you call the require() function.
The Sequelize instance method sync() is used to synchronize your Sequelize model with your database tables. The synchronization happens at the table level. When your table doesn't exist the sync() method will generate and run a CREATE TABLE statement for you.24-Jan-2022.
This project aims to create Sequelize models from existing schema https://github.com/sequelize/sequelize-auto
A tool to automatically generate models for SequelizeJS
via the command line.
npm install -g sequelize-auto
sequelize-auto -h <host> -d <database> -u <user> -x [password] -p [port] --dialect [dialect] -c [/path/to/config] -o [/path/to/models]
-h, --host IP/Hostname for the database. [required] -d, --database Database name. [required] -u, --user Username for database. [required] -x, --pass Password for database. -p, --port Port number for database. -c, --config JSON file for sending additional options to the Sequelize object. -o, --output What directory to place the models. -e, --dialect The dialect/engine that you're using: postgres, mysql, sqlite
Example
sequelize-auto -o "./models" -d sequelize_auto_test -h localhost -u daniel -p 5432 -x my_password -e postgres
Produces a file/files such as ./models/Users.js
which looks like this:
/* jshint indent: 2 */ module.exports = function(sequelize, DataTypes) { return sequelize.define('Users', { username: { type: DataTypes.STRING, allowNull: true, defaultValue: null }, touchedAt: { type: DataTypes.DATE, allowNull: true, defaultValue: null }, aNumber: { type: DataTypes.INTEGER, allowNull: true, defaultValue: null }, id: { type: DataTypes.INTEGER, primaryKey: true }, createdAt: { type: DataTypes.DATE, allowNull: false, defaultValue: null }, updatedAt: { type: DataTypes.DATE, allowNull: false, defaultValue: null } }); };
Which makes it easy for you to simply Sequelize.import
it.
with Sequelize you have to define the structure of the model inside your code. Doing so, Sequelize assumes a specific database schema unless something is overwritten. So in short: No, sequelize cannot mirror the database.
Hope that helps :)
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