What are the main differences between SQLite and Realm databases in terms of functionality and usage?

SQLite and Realm are two popular databases for mobile applications, but they differ in architecture and capabilities.

SQLite:

• A relational database that uses SQL for queries.
• Built into Android, does not require additional libraries.
• Well-suited for complex queries and transactions.
• Requires manual management of schema and data transformation (e.g., through ORM).

Realm:

• An object-oriented database that works directly with objects.
• Does not use SQL; queries are written through the Realm API.
• Provides convenient synchronous and asynchronous data access.
• Supports automatic schema migration and reactive updates.

Example of using Realm:

val realm = Realm.getDefaultInstance()
realm.executeTransaction { r ->
    val person = r.createObject(Person::class.java)
    person.name = "Ivan"
}

In conclusion, SQLite is a more versatile and standard tool, but requires more effort to work with, whereas Realm simplifies data handling through its object model and additional features.