PGres

Introduction

Pgres is just another ORM used for querying postgres databases. It is made to make the setup process very easy. This package depends on the package pg-promise.

NOTE: Pgres can only be used to do CRUD operations on the database. It does not support any schema migration.

Usage

Make a connection object as below:

import { DBConnection } from "@try-catch-80/pgres";

const connection = new DBConnection({
  host: 'localhost',
  port: 5432,
  user: '<your_username>',
  password: '<your_password>',
  database: '<your_dbname>'
});

---

*** For NextJS applications, you might get a warning in your console,

  WARNING: Creating a duplicate database object for the same connection.

In this case use DBConnectionSingleton instead of DBConnection.

---

Make models according to your database by extending the model class from BaseModel:

import { BaseModel } from "@try-catch-80/pgres";

export class YourModel extends BaseModel {
  constructor({
    name = '', // these are just named parameters. implement this as you like
    email = '',
    description = ''
  } = {}) {
    const data = {
      name,
      email,
      description
    };

    super({ table: 'users', data, connection }); // You have to call super() to pass the necessary data to BaseModel
    
    /*
      super takes 3 named parameters:
      table (The name of your db table),
      data (The model data),
      connection (The DBConnection object)
    */
  }
}

You have some methods out-of-the-box, such as:
list: gets all the data for a particular model
findById: gets data by primary key which should be spelled 'id' in the database. Takes parameter id
save: doesn't take any parameter. Saves data to the database after initialization
update: takes model object as parameter. updates the object
delete: takes model object as parameter. deletes the object

Eample:

Code for list:

import { YourModel } from 'YourModel.js';

const model = new YourModel();
const result = await model.list(); // gives you a list back in json format

Code for save:

import { YourModel } from 'YourModel.js';

const model = new YourModel({
  name: 'Jon Doe',
  email: 'jon@doe.com',
  description: 'A software developer'
});

await model.save();

Code for findByEmail, update, delete:

import { YourModel } from 'YourModel.js';

const model = new YourModel();
const result = await model.findById(id);

// Change the result as neccessary for update
result.description = 'An open-source software enthusiast';

await model.update(result);


// Delete function is similar
await model.delete(result);

Advanced Usage

To make custom queries to the database, you can add methods to your extended model class. For example:

export class YourModel extends BaseModel {
  // ...rest of the code

  customQuery() {
    return this.connection.db.any(`SELECT * FROM db_table`);
  }
}

To use the connection.db instance, refer to the pg-promise documentaion.