How to create a new Sequelize dialect, for example DB2

Question

Sequelize supports five flavours of DBMS. In my project, we have a legacy database located in an IBM DB2, which is not in that list. There exists a node driver for DB2, published by IBM.

1. Is there a documentation on how to create such a new dialect for Sequelize?
2. Is it encouraged?

Answer 1

According to latest for v4.0.0 It will throw an error if you use any thing other than five specified dialects, You can change the drivers but not the dialect. 1.So you cannot do it 2. It is not encouraged

      var Dialect;
  // Requiring the dialect in a switch-case to keep the
  // require calls static. (Browserify fix)
  switch (this.getDialect()){
    case 'mariadb':
      Dialect = require('./dialects/mariadb');
      break;
    case 'mssql':
      Dialect = require('./dialects/mssql');
      break;
    case 'mysql':
      Dialect = require('./dialects/mysql');
      break;
    case 'postgres':
      Dialect = require('./dialects/postgres');
      break;
    case 'sqlite':
      Dialect = require('./dialects/sqlite');
      break;
    default:
      throw new Error('The dialect ' + this.getDialect() + ' is not supported. Supported dialects: mariadb, mssql, mysql, postgres, and sqlite.');
  }

https://github.com/sequelize/sequelize/blob/3e5b8772ef75169685fc96024366bca9958fee63/lib/sequelize.js#L91