MongoDB vs SQL Server Express

MongoDB queries can be very fast because the data is usually all in one place and can easily be retrieved in a single lookup. But this is true only when the data is truly a document. When it's trying to emulate a relational model it starts to become really slow because it may have to perform many independent queries to retrieve a single document.

Miles above other databases in educational resources.

As Node.js uses JavaScript there's no need to map the returned JSON data from MongoDB, as JavaScript is a superset of JSON. Essentially solving object-relational impedance mismatch by its very nature. Working with JSON is also easier overall as it more easily fits into how you would represent data on the client.

Mongo is very flexible in that it doesn't require a unified data structure across all objects. So it's rather easy to use.

MongoDB has powerful sharding and scaling capabilities for when the data stored in the database gets so large that a single machine may not be able to store all of it. Sharding solves this problem through horizontal scaling. Mongo gives developers the ability to easily and painlessly add or remove as many machines as needed.

SQL Server Express has deep integration with Visual Studio, Visual Web Developer and SQL Server Management allowing for ease-of-use and rich table and query designers. It may be the best choice for someone who develops in the Microsoft environment.

"Manage SQL Server Express databases with SQL Server Management Studio Express. Connect to local SQL Server Express databases and manage objects with full Object Explorer integration. Write, execute, and test queries by using visual query plans, and access management and maintenance options."

With a variety of versions to choose from the SQL Server Express version is free of charge. It is capable of upgrading to higher tiers, but that requires a fee.

Can be deployed to all editions of SQL Server and Microsoft Azure SQL Database