sequelize association test

rootfs_overlay/lkmc/nodejs/sequelize/association.js

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+#!/usr/bin/env node
+
+const assert = require('assert');
+const path = require('path');
+
+const { Sequelize, DataTypes } = require('sequelize');
+
+const sequelize = new Sequelize({
+  dialect: 'sqlite',
+  storage: 'tmp.' + path.basename(__filename) + '.sqlite',
+});
+(async () => {
+const Comment = sequelize.define('Comment', {
+  body: { type: DataTypes.STRING },
+}, {});
+const User = sequelize.define('User', {
+  name: { type: DataTypes.STRING },
+}, {});
+User.hasMany(Comment)
+Comment.belongsTo(User)
+await sequelize.sync({force: true});
+const u0 = await User.create({name: 'u0'})
+const u1 = await User.create({name: 'u1'})
+await Comment.create({body: 'u0c0', UserId: u0.id});
+await Comment.create({body: 'u0c1', UserId: u0.id});
+await Comment.create({body: 'u1c0', UserId: u1.id});
+
+// Direct way.
+{
+  const u0Comments = await Comment.findAll({
+    where: { UserId: u0.id },
+    order: [['id', 'ASC']],
+  });
+  assert(u0Comments[0].body === 'u0c0');
+  assert(u0Comments[1].body === 'u0c1');
+  assert(u0Comments[0].UserId === u0.id);
+  assert(u0Comments[1].UserId === u0.id);
+  // Not added as an object by default. Would require extra query.
+  assert(u0Comments[0].User === undefined);
+  assert(u0Comments[1].User === undefined);
+}
+
+// Include data from the other side of the association in the query.
+{
+  const u0Comments = await Comment.findAll({
+    where: { UserId: u0.id },
+    order: [['id', 'ASC']],
+    include: [{ model: User }],
+  });
+  assert(u0Comments[0].body === 'u0c0');
+  assert(u0Comments[1].body === 'u0c1');
+  assert(u0Comments[0].UserId === u0.id);
+  assert(u0Comments[1].UserId === u0.id);
+  // These did get added now.
+  assert(u0Comments[0].User.name === 'u0');
+  assert(u0Comments[1].User.name === 'u0');
+}
+
+// Nicer higher level way.
+{
+  const u0Comments = await u0.getComments({
+    include: [{ model: User }],
+  });
+  assert(u0Comments[0].body === 'u0c0');
+  assert(u0Comments[1].body === 'u0c1');
+  assert(u0Comments[0].User.name === 'u0');
+  assert(u0Comments[1].User.name === 'u0');
+}
+
+// No way to create new item with association without explicit foreign key??
+// https://stackoverflow.com/questions/34059081/how-do-i-reference-an-association-when-creating-a-row-in-sequelize-without-assum
+// This does not work as we would like:
+{
+  await Comment.create({body: 'u0c2', User: u0});
+  // We'd want 3 here.
+  assert((await Comment.findAll({
+    where: { UserId: u0.id },
+  })).length === 2);
+}
+
+// Removal auto-cascades.
+const u0id = u0.id
+await u0.destroy()
+assert((await Comment.findAll({
+  where: { UserId: u0id },
+})).length === 0);
+assert((await Comment.findAll({
+  where: { UserId: u1.id },
+})).length === 1);
+
+await sequelize.close();
+})();

rootfs_overlay/lkmc/nodejs/sequelize/index.js

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+#!/usr/bin/env node
+
+// https://cirosantilli.com/sequelize
+//
+// Before running this:
+// * ensure that you can use peer authentication without password
+//   from the command line, i.e. `psql` works
+// * create the database for our test:
+//   ``
+//   createdb lkmc-nodejs
+//   ``
+
+const assert = require('assert');
+const path = require('path');
+
+const { Sequelize, DataTypes } = require('sequelize');
+
+// To use the URI syntax, we need an explcit username and password.
+// But the second constructor works with peer authentication.
+// https://stackoverflow.com/questions/46207155/sequelize-and-peer-authentication-for-postgres
+//
+// Fails
+//const sequelize = new Sequelize('postgres://user:password@localhost:5432/lkmc-nodejs')
+//
+// Works with peer authentication:
+//const sequelize = new Sequelize('lkmc-nodejs', undefined, undefined, {
+//  host: '/var/run/postgresql',
+//  dialect: 'postgres',
+//  logging: false,
+//});
+const sequelize = new Sequelize({
+  dialect: 'sqlite',
+  storage: 'tmp.' + path.basename(__filename) + '.sqlite',
+});
+
+// OMG fuck this asynchronous bullshit:
+// https://stackoverflow.com/questions/39928452/execute-sequelize-queries-synchronously/43250120
+(async () => {
+
+// Connection sanity check.
+// https://stackoverflow.com/questions/19429152/check-mysql-connection-in-sequelize/31115934
+await sequelize.authenticate();
+
+const IntegerNames = sequelize.define('IntegerNames', {
+  value: {
+    type: DataTypes.INTEGER,
+    allowNull: false
+  },
+  name: {
+    type: DataTypes.STRING,
+  },
+}, {});
+
+// Create the database defined by `sequelize.define`.
+await IntegerNames.sync({force: true})
+// After this:
+//
+// psql lkmc-nodejs -c '\dt'
+//
+// gives:
+//
+//            List of relations
+//  Schema |     Name     | Type  | Owner
+// --------+--------------+-------+-------
+//  public | IntegerNames | table | ciro
+// (2 rows)
+//
+// and:
+//
+// psql lkmc-nodejs -c '\d+ "IntegerNames"'
+//
+// gives:
+//
+//   Column   |           Type           | Collation | Nullable |                  Default                   | Storage  | Stats target | Description
+// -----------+--------------------------+-----------+----------+--------------------------------------------+----------+--------------+-------------
+//  id        | integer                  |           | not null | nextval('"IntegerNames_id_seq"'::regclass) | plain    |              |
+//  value     | integer                  |           | not null |                                            | plain    |              |
+//  name      | character varying(255)   |           |          |                                            | extended |              |
+//  createdAt | timestamp with time zone |           | not null |                                            | plain    |              |
+//  updatedAt | timestamp with time zone |           | not null |                                            | plain    |              |
+// Indexes:
+//     "IntegerNames_pkey" PRIMARY KEY, btree (id)
+
+await IntegerNames.create({value: 2, name: 'two'});
+await IntegerNames.create({value: 3, name: 'three'});
+await IntegerNames.create({value: 5, name: 'five'});
+// psql lkmc-nodejs -c 'SELECT * FROM "IntegerNames";'
+//
+// gives:
+//
+//  id | value | name  |         createdAt          |         updatedAt
+// ----+-------+-------+----------------------------+----------------------------
+//   1 |     2 | two   | 2021-03-19 19:12:08.436+00 | 2021-03-19 19:12:08.436+00
+//   2 |     3 | three | 2021-03-19 19:12:08.436+00 | 2021-03-19 19:12:08.436+00
+//   3 |     5 | five  | 2021-03-19 19:12:08.437+00 | 2021-03-19 19:12:08.437+00
+// (3 rows)
+
+let integerNames = await IntegerNames.findAll({
+  where: {
+    value: 2
+  }
+});
+assert(integerNames[0].name === 'two');
+
+// Truncate all tables.
+// https://stackoverflow.com/questions/47816162/wipe-all-tables-in-a-schema-sequelize-nodejs/66985334#66985334
+await sequelize.truncate();
+assert((await IntegerNames.findAll()).length === 0);
+
+// Datetime. Automatically converts to/from date objects.
+const Dates = sequelize.define('Dates', {
+  date: {
+    type: DataTypes.DATE,
+  },
+}, {});
+await Dates.sync({force: true})
+let dateCreate = await Dates.create({date: new Date(2000, 0, 1, 2, 3, 4, 5)});
+await Dates.create({date: new Date(2000, 0, 1, 2, 3, 4, 6)});
+await Dates.create({date: new Date(2000, 0, 1, 2, 3, 4, 7)});
+let date = await Dates.findOne({
+  order: [
+    ['date', 'ASC'],
+  ],
+});
+assert(date.date.getTime() === new Date(2000, 0, 1, 2, 3, 4, 5).getTime());
+assert(date.date.getTime() === dateCreate.date.getTime());
+
+// Otherwise it hangs for 10 seconds, it seems that it keeps the connection alive.
+// https://stackoverflow.com/questions/28253831/recreating-database-sequelizejs-is-slow
+// https://github.com/sequelize/sequelize/issues/8468
+await sequelize.close();
+})();