It provide schema validation, middleware, and a robust object-oriented framework for building RESTful APIs. Mongoose gets approximately 6 million downloads a month on npm and the documentation site gets over 1.5M hits per month. Once the collection is created it can be used to invoke MongoDB function calls to access documents in the database. For example, collection.count() returns the number of documents in the collection. Rather than requiring navigational logic in the application to traverse the database, data is retrieved based on a shared key value between the Account and Transaction.
This database tier is not considered suitable for production websites because it has no redundancy, but it is great for development and prototyping. We’re using it here because it is free and easy to set up, and because MongoDB Atlas is a popular database as a service vendor that you might reasonably choose for your production database . We can save our references to the related document by assigning the _id value. Below we create an author, then a story, and assign the author id to our story’s author field. If you don’t specify a callback then the API will return a variable of type Query. You can use this query object to build up your query and then execute it later using the exec() method.
In the example above this is done by calling the accountsDb.close() function to stop the connection and free up any resources devoted to it. In the early 1980’s a new type of database based on the Structured Query Language began to take hold. The main advantage of a SQL database had over a CODASYL database is that manipulating data was simpler since data in a SQL database is organized relationally rather than physically. This meant that application programs became simpler to write and maintain. The require(‘mongoose’) call above returns a Singleton object. It means that the first time you call require(‘mongoose’), it is creating an instance of the huffy mountain bike class and returning it.
In the above code, the ProductService is injected into the constructor. Hence, NestJS will provide a ProductService instance to the controller at runtime. Now, you can run standard POST, GET, PUT and DELETE request handlers to perform the Create, Add, Update and Delete operations respectively. In this article, you will learn how to effectively build a scalable application using NestJS in 5 simple steps.
The benefit of using is that we have a schema to work against in our application code and an explicit relationship between our MongoDB documents and the Mongoose models within our application. The downside is that we can only create blog posts and they have to follow the above defined schema. If we change our Mongoose schema, we are changing the relationship completely, and if you’re going through rapid development, this can greatly slow you down. Once you’ve created a schema you can use it to create models. The model represents a collection of documents in the database that you can search, while the model’s instances represent individual documents that you can save and retrieve.
This could be as simple as merely defining the new relationship, but it always required careful planning and often resulted in extensive database reorganization. The earliest databases, up through the mid-1980’s, were so-called CODASYL databases. These organized data into records and related occurrences of different record types to one another using hashes to form a network. Suppose that we want to track when a record was created and last updated on every collection in our database. Instead of repeating the above process, we can create a plugin and apply it to every schema.
This code establishes a /foods endpoint for GET requests (note the plural ‘s’). The Mongoose query function find() returns all objects with matching parameters. Since no parameters have been provided, it will return all of the items in the database. MongoDB is one of the most widely used No-SQL databases in the developer world today.