Auto Increment

Introduction

Model id is an integer field that is auto-incremented by default, which is fully managed by the model class, you can manually assign value to it or manually generate it as well.

tip

The id is generated if and only if the model does not have an id value in its data, this means it works only with newly created models.

Auto Incrementing

By default, the id field is auto-incremented, which means that when saving a new model, the id field will be automatically generated, let's take an example:

src/app.ts

import { Category } from "./models/category";

async function main() {
  const category = new Category({
    name: "Sports",
  });

  await category.save();

  console.log(category.id); // 512344
}

main();

This will auto generate a random id for the model by default.

Auto Incrementing with a custom start value

By default the initial id value is randomly generated for an integer between 10000 and 499999, you can change this value by setting the initialId property in the model class, let's take an example:

src/models/category.ts

import { Model } from "@mongez/monpulse";

export class Category extends Model {
  /**
   * The collection name
   */
  public static collection = "categories";

  /**
   * The initial id value
   */
  public static initialId = 1;
}

This will start the auto incrementing from 1 instead of a random value.

The next auto generated id

Same applies to the next generated id, it is generated randomly and sums the initial id with a random number between 1000 and 9999, you can change this value by setting the incrementIdBy property in the model class, let's take an example:

src/models/category.ts

import { Model } from "@mongez/monpulse";

export class Category extends Model {
  /**
   * The collection name
   */
  public static collection = "categories";

  /**
   * The initial id value
   */
  public static initialId = 1;

  /**
   * The increment value
   */
  public static incrementIdBy = 1;
}

In that example, our category model will mostly interact exactly like the typical auto incrementing id in SQL databases, however, for large scale applications, it is recommended to use a random id instead of an auto incrementing one so guessing the next id will be impossible.

Manually Generating the next ID

In some scenarios, you might need to generate the next id even before saving the model, to achieve this we can use the generateNextId method, let's take an example:

src/app.ts

import { Category } from "./models/category";

async function main() {
  const category = new Category({
    name: "Sports",
  });

  const nextId = await category.generateNextId();

  console.log(nextId); // 512344
  console.log(category.id); // 512344
}

main();

This will generate the next id and assign it to the id property of the model.