Which database should you choose for iOS application development?

July 5th, 2017  | By

Database the most important part of the application that can make your application faster if you have a right choice and on the other hand it can also make you application slower if you don't have a right selection of the database according to the requirement of the application. If you want to make a great app that runs fast and just works (no bugs allowed) you’ll have to think about all development aspects of your app carefully.

The most common options for iOS databases are SQLite and Core Data. But there is also new and best option Realm.

In this article, we will explain the difference between SQLite and Core Data and how Realm differs from SQLite and Core data and why we should choose Realm in iOS application development.


SQLite is the most used and open source database. It implements a transactional SQL database engine with no configuration. It delivers a simple and user-friendly programming interface as it is written in ANSI-C. SQLite is also very small and light and the complete database can be stored in one cross-platform disk file.

The reason why we should use SQLite in our application.

  • SQLite does not have a separate server process. It reads and writes directly to ordinary disk files.
  • Zero-configuration
  • Safe access from multiple processes and threads
  • Stores data in tables with one or more columns that contain a specific type of data.
  • Have Data Constrains feature.
  • Operates on data, stored on disk.
  • Can Drop table and Edit data without loading them in memory.


Core Data:

Core Data is the second main iOS storage technology available to app developers. Depending on the type of data and the amount of data you need to manage and store, both SQLite and Core Data have their pros and cons. Core Data focuses more on objects than the traditional table database methods. With Core Data, you are actually storing contents of an object which is represented by a class

There is some difference between SQLite and Core data in term of memory

  • Uses more memory than SQLite
  • Uses more storage space than SQLite
  • Faster in fetching records than SQLite.
  • Don't have Data Constraints, if required need to implement business logic.
  • Operates on in memory.(data needs to be loaded from disk to memory)
  • Need to load entire data if we need to drop table or update
  • But Core data is Faster than SQLite


Realm was designed to be faster and more efficient than the previous database solutions. This new solution is a cross-platform mobile database called Realm. It is available in Objective-C and Swift, and it’s designed for iOS and Android.

What’s really great about it is that you can handle all the work with a couple of lines of code. Realm is very easy to install and faster to work with compared to SQLite and Core Data. Also, the database files are shareable among iOS and Android.

If you are designing an app with a lot of records and for a large number of users, you need to pay special attention to scalability from the very beginning. Realm is great at this and it allows you to handle a lot of data fast.To get started with Realm, all you need is at least iOS 8 or OS X 10.9. Older versions don’t support this new straightforward solution for managing local storage and databases.

Why Realm:

Realm is incredibly fast and easy to use and you will see everything you need will be accomplished with just couple of lines of code regardless it’s reading or writing to database. Here I will try to collect all advantages and reasons for why making Realm is the best choice to work with database in your mobile app:

  • Easy Installation: As you will see in next section about working with Realm. Installing Realm is more easy as you imagine. With simple command in Cocoapods, you here to go to work with Realm.
  • Speed: Realm is incredibly fast library to work with database. Realm is faster than SQLite and CoreData and the benchmarks here are the best evidence for that.
  • Cross Platform: Realm database files are cross platform and can be shared among iOS and Android. Regardless you work with Java, Objective-C, or Swift, you will use your high-level models.
  • Scalability: Scalability is very important to be considered while developing your mobile app especially if your app deals with a large number of users and a massive number of records. You should consider that from the beginning while designing and choosing your tools to be used. Realm is ready for scalability and works with large data in no time. You will bring speed and smoothing to your app while using Realm.
  • Good Documentation & Support: Realm team has provided readable, well organized and rich documentation about Ream. If you have any problems you can reach them via Twitter, Github or StackOverflow.
  • Trusted: Realm has been used by the giant of startups and companies in their mobile apps like Pinterest, Dubsmash, and Hipmunk.
  • Free: with all these awesome features, Realm is completely free.



If you have to choose between core data and SQLite then What should you use? Core Data or SQLite? In short, If you need a lightweight solution and don’t need Core Data’s feature set, then SQLite may fit your needs.

But on the other hand, if you are managing a complex object graph with many entities, attributes, and relationships, then Core Data is definitely worth considering.

Finally, comes on Realm after reading all the points, you will be well known about Realm there is nothing to say about Realm it is the best option.

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