ArangoDB vs SQL Server Express

You can model your data as documents or as a graph - no data model lock-in. You can even combine both models and use them in a single AQL query.

Unlike many NoSQL databases, ArangoDB does support joins in AQL queries.

You can extend ArangoDB using JavaScript that runs directly on the Server (Google V8). You can build data-centric microservices that aggregate, validate, transform or enrich data (It's up to you, plain JavaScript) and provide those via a custom API route.

You can use ACID Transactions for short and small data retrieval and/or modification operations in ArangoDB.

ArangoDB has a very good Java Driver for synchronous and asynchronous. In addition the team there is working on a Spring Data integration.

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