ios – Creating an r-tree index desk for bounding field

I am at present engaged on establishing a SQLite database utilizing GRDB to retailer a quite simple location-based mannequin (I’ve simplified the mannequin for the aim of this query)

struct ExampleModel: Codable, Identifiable, FetchableRecord, PersistableRecord {
    let id: String
    let longitude: Double
    let latitude: Double
}

Nonetheless, I additionally must create an r-tree index desk to permit customers to cross a bounding field and retrieve all the persevered parts inside this bounding field

struct BoundingBox {
    let minX: Double
    let maxX: Double
    let minY: Double
    let maxY: Double
}

It is the primary time I am having to implement a performance like this and I am completely misplaced on the way to get this r-tree index desk up and operating. What would the database schema seem like and the way would I even get a bounding field if all I’ve is a mannequin with a particular location? I might recognize some ideas!