5/6/2023 0 Comments Nodejs mongodb![]() To add more books, we can push to the books array and save the changes. The author will have an array of books with one book for each author in the array. This will create a new connection to the MongoDB database and then convert a normal array of JavaScript objects into data we can persistently access. These schemas are flexible but help us define what we want our data to look like.įor the author model, we define a model schema that can reference documents in another collection: const mongoose = require('mongoose') The first thing to do is set up our models in Mongoose. Mongoose is an ORM (stands for Object Relationship Mapper) that is a helper for MongoDB kind of like how ActiveRecord and Eloquent are helpers for working with relational data. There is a helper npm package for working with MongoDB called mongoose that we’re going to use for illustrative purposes in this tutorial. MongoDB doesn’t use joins though, so how do we achieve this functionality? On the books table, we’d store an author_id, setting up the relationship between authors and books in the SQL world. These results would give us the author with id 1234 and all the books that they’ve written. In Laravel, using Eloquent, we could do: $authorWithBooks = Author::find(1234)->books() In Ruby On Rails, using Active Record finding, an author and related posts could look like: authorWithBooks = Author.find 1234, :include => Frameworks like Ruby On Rails and Laravel have abstracted this functionality for developers, making it possible to write PHP or Ruby to grab related information. ![]() This will grab information from both tables and display the results in a single dataset for us. For example, if we had a SQL database with two tables, books and authors, we could get all the books that belong to an author like so: SELECT b.id AS ‘Post ID’, b.title AS ‘Book Title’, a.name AS ‘Author Name`, a.id AS ‘Author ID’ In SQL databases, we get database relationships using joins. MySQLĮmbedded documents, $lookup & $graphLookup You can find the whole source code for this tutorial in this GitHub repo. In the table below (provided by MongoDB) you’ll see how traditional aspects of SQL databases stack up against their MongoDB equivalents. In this tutorial, we’re going to set up a Node.js server application, connect it to MongoDB and demonstrate how relationships work between MongoDB Collections. This means there aren’t database migrations to worry about and data models can grow and change. Additionally, MongoDB has flexible schema. This structure lends itself well to building Javascript applications that communicate with JSON. ![]() MongoDB is different from traditional, SQL databases like MySQL and PostgreSQL in that data is stored in binary JSON-like objects called BSON). It’s popular in the Node.js community and a viable database solution for building real-world applications. MongoDB is a NoSQL document-oriented database. ![]()
0 Comments
Leave a Reply. |