The fans of modern and agile software development usually propose to use schemaless database engines to allow for greater flexibility, in particular during the early rapid prototyping phase of IT projects. The more traditionally minded insist that having a strict schema that is enforced by the persistence layer throughout the lifetime of a project is necessary to ensure quality and security.In this post I would like to explain briefly, why I believe that both groups are completely right and why this is not so paradoxical as it sounds at first glance. I am one of the developers of ArangoDB,..

This is the second blog post on building hypermedia APIs with the focus on API design. In part 1 Lucas describes the concept of links in JSON.

Imagine we have an API where people can like books and other people can then see, who likes a certain book. We want this API to be highly connected: We don’t want to look up URLs in a documentation, we want to follow links as we know it from the world wide web. All we want to do as the author of the API is give our users a single URL from which they can then follow links to all other resources. This is similar to the way we would do this with a..

MongoDB is a document DB whereas ArangoDB is a multi-model DB supporting documents, graphs and key/values within a single database. When it comes to data modeling and data querying, they pursue somewhat different approaches.

In a Nutshell: In MongoDB, data modeling is “aggregate-oriented”, avoiding relations and joins. On the other side, everybody has probably used relational databases which organize the data in tables with relations and try to avoid as much redundancy as possible. Both approaches have their pros and cons. ArangoDB is somewhat in-between: You can both model and query your..

I recently had the chance to visit FullStack London, a well organized conference. Thanks a lot to Skills Matter. FullStack was opened by Douglas Crockford about “The Better Parts” of ES6. I cannot wait to start using them. Douglas was followed by Isaac Schlueter talking about open source in companies. Although this talk was not technical I learned a lot and it was very inspiring.

The remainder of the conference was all about using JavaScript mostly on server-side using Node.js or in robotics. As robotics is not my kind of topic I visited the talks about server-side JS. They confirmed my..

A while ago we wrote some blog article that explained how ArangoDB uses disk space. That article compared the disk usage of ArangoDB, CouchDB, and MongoDB for loading some particular datasets. In this post, we’ll show in more detail the disk usage of ArangoDB for insert, update, and delete operations. We’ll also compare it to CouchDB for reference.

In this post we’ll explain how ArangoDB stores collection data on disk and look at its storage space requirements, compared to other popular NoSQL databases such as CouchDB and MongoDB.

How ArangoDB allocates disk space

ArangoDB stores documents in collections. The collection data is persisted on disk so it does not get lost in case of a server restart.

UNQL started with quite some hype last year. However, after some burst of activity the project came to a hold. So it seems, that – at least as a project – UNQL has been a failure. IMHO one of the major issues with the current UNQL is, that it tries to cover everything in NoSQL, from key-value stores to document-stores to graph-database. Basically you end up with greatest common divisor – namely key-value access. But with graph structures and also document-structures you really want to supports joins,..

Last week AvocadoDB got mentioned in “nosql weekly” and the project achieved a huge amount of public interest especially from Japan. Awesome! 🙂

In this context Mr. Fiber asked on twitter what the use of skip list indices in AvocadoDB is. Here’s a short video reply by chief architect martin Schoenert. Got an opinion on this? – we’d love to hear your thoughts on this in the comments.

AvocadoDB uses AppendOnly memory-mapped files with frequent fsync. Derived data (indices, etc.) is stored in the main memory only. This article explains why that particular combination leads to high performance and consistent data at the same time―even in case of a system failure.

Classical database systems – a bulk of data and insufficient main memory

Put simply, there are three possible settings regarding databases:

• Setting 1: All data fits into the main memory.
• Setting 2: The complete data pool does..

Before we started programming the new open source NoSQL database, we reflected which design objectives to achieve or to drop. This article summarizes our considerations.

In a nutshell:

• Schema-free schemas with shapes: Inherent structures at hand are automatically recognized and subsequently optimized.
• Querying: ArangoDB is able to accomplish complex operations on the provided data (query-by-example and query-language).
• Application Server: ArangoDB is able to act as application server on Javascript-devised routines.
• Mostly memory/durability: ArangoDB is memory-based including frequent file..