My Scenario,
I am working on a desktop based application. Where My big challenge is keeping data into relational DB(Offline) and sync accordingly(Company have their own syncing algorithm). I am using Electron and VueJS as client side. For building the desktop app I'm using electron-builder. I am able to write migrations with raw SQL or various ORM.
What I want?
While I'll install into a desktop, I want to create the database file and apply all the migrations on the client's computer. I just don't know that part how to do that. I also looked into Electron Builder Docs. But didn't understand. I need an example, any idea.
Please help me. Thanks
After doing a lot of research I found an awesome solution provided by sequalize.js. I found a library Umzug Github. Let's look at the implementation...
/**
* Created by Ashraful Islam
*/
const path = require('path');
const Umzug = require('umzug');
const database = /* Imported my database config here */;
const umzug = new Umzug({
storage: 'sequelize',
storageOptions: {
sequelize: database
},
// see: https://github.com/sequelize/umzug/issues/17
migrations: {
params: [
database.getQueryInterface(), // queryInterface
database.constructor, // DataTypes
function () {
throw new Error('Migration tried to use old style "done" callback. Please upgrade to "umzug" and return a promise instead.');
}
],
path: './migrations',
pattern: /\.js$/
},
logging: function () {
console.log.apply(null, arguments);
}
});
function logUmzugEvent(eventName) {
return function (name, migration) {
console.log(`${name} ${eventName}`);
}
}
function runMigrations() {
return umzug.up();
}
umzug.on('migrating', logUmzugEvent('migrating'));
umzug.on('migrated', logUmzugEvent('migrated'));
umzug.on('reverting', logUmzugEvent('reverting'));
umzug.on('reverted', logUmzugEvent('reverted'));
module.exports = {
migrate: runMigrations
};
Idea behind the scene
I clearly declare the migration directory. Also, define the file matching pattern. Umzug just read files from there and run the DB migration. An example migration file is following...
// 000_Initial.js
"use strict";
module.exports = {
up: function(migration, DataTypes) {
return migration.createTable('Sessions', {
sid: {
type: DataTypes.STRING,
allowNull: false
},
data: {
type: DataTypes.STRING,
allowNull: false
},
createdAt: {
type: DataTypes.DATE
},
updatedAt: {
type: DataTypes.DATE
}
}).then(function() {
return migration.addIndex('Sessions', ['sid']);
});
},
down: function(migration, DataTypes) {
return migration.dropTable('Sessions');
}
};