Database Integration in Express.js

Web applications often need to store data beyond the lifespan of a single server session. While arrays and objects can store data temporarily, they do not persist across server restarts, making a database necessary for long-term data management.

A database solves this problem by providing a structured way to store, retrieve, and manipulate data. With a database, we can:

• Store and retrieve data across multiple server instances.

• Query data efficiently using indexes.

• Ensure data integrity through structured schemas.

• Scale applications to handle large amounts of data.

SQL vs. NoSQL: Choosing the right database

Databases fall into two broad categories:

• SQL (relational): These databases store data in tables with predefined schemas. Examples include MySQL and PostgreSQL. They use SQL for querying and ensure data consistency through strict relationships between tables.

• NoSQL (Non-relational): These databases store data in flexible formats like key-value pairs, documents, or graphs. Examples include MongoDB and Firebase. They allow dynamic schemas and scale horizontally to handle large amounts of data efficiently.

For this course, we use MongoDB, a NoSQL database, because it integrates well with Express.js and stores data in an easy-to-read JSON-like format.

Connecting to MongoDB using Mongoose

To interact with MongoDB in an Express.js application, we use Mongoose, an Object ...