Note: This is an updated version of an earlier Mobile Database Comparison. Last Update: 2020.

What is a mobile database?

While Wikipedia defines a mobile database as “Mobile computing devices (e.g., smartphones and PDAs) store and share data over a mobile network, or a database which is actually stored by the mobile device,” we solely refer to the latter ones as a mobile database. Meaning only databases that run on the mobile device (as the edge device) itself, locally, and store the data on the device. Therefore, we also refer to it as “on-device” database.

What is an edge database?

The term edge database is too young to have a Wikipedia article. However, we see it used in the IoT industry increasingly. In the field of IoT applications, it is important to distinguish databases that run locally – “on the edge” – as opposed to “in the cloud”. A mobile database is a subset of edge databases, meaning the only difference is the device the database runs on. The main difference is the operating system support: There simply are edge databases that do not run on Android and / or iOS. Thus, these databases, while small enough for Edge Computing, and indeed qualifying as edge databases, are not suited for typical mobile devices, and therefore no mobile database.

What are the advantages and disadvantages of working with SQLite?

SQLite is easily the most established edge database and probably the only “established” mobile database. SQLite is public domain and maintained by Richard Hipp. SQLite database has been around since the year 2000 and been embedded with iOS and Android since the beginning. SQLite is a relational database.

What are SQLite alternatives?

There are plenty of alternatives to working with SQLite directly. If you simply want to avoid writing lots of SQL and boilerplate code, you can use an object abstraction on top of SQLite. This abstraction layer is usually an ORM (object/relational mapper), e.g. greenDAO. While an ORM makes it easy to use SQLite at the beginning, there typically comes a point “where you hit SQLite”; so even when using an abstraction layer you need to understand SQLite and SQL in the longrun.

However, if you rather seek a complete replacement for SQLite, there are a few alternative databases: Couchbase Lite, Interbase, LevelDB, ObjectBox, Oracle Berkeley DB (formerly Oracle’s mobile database was “Oracle Database Lite”), Realm (now Mongo Realm), SnappyDB, SQL Anywhere, and UnQLite.

Obviously, if your also looking for alternatives that run in the cloud, there are a lot of cloud / server options out there that you can use as a replacement like e.g. Firebase. Though, with these your app will not work offline, response rates will be slower than with an on-device database and cannot be guaranteed, and last not least you will have much higher networking / cloud costs. You can find out more about the benefits of Edge Computing.

To give you an overview, we have compiled a small comparison table:

Side note: According to the database of databases there are more than 700 databases as of 2020. However, that list does include hobby projects. DB-engines “only” lists databases that have significant traction and are well-maintained; they still count more than 300 databases as of 2020.

If you are interested in an indication of the diffusion rate of databases and mobile databases, check out the following database popularity ranking: http://db-engines.com/en/ran.

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