/ Database

Swift library to make easy using local document-oriented database in iOS apps

Swift library to make easy using local document-oriented database in iOS apps

StorageDone-iOS

Swift library to make easy use local document-oriented databases in iOS apps.

Installation

To install StorageDone add this line to your Podfile

pod 'StorageDone'

Usage

StorageDone lets you save Codable models in a local database very easily.

First create a model

struct Teacher: Codable {
    let id: String
    let name: String?
    let surname: String?
    let age: Int?
    let cv: String?
}

Then create a StorageDoneDatabase object and save an instance of a Codable model in it

let teacher = Teacher(id: "id1", name: "Sarah", surname: "Jones", age: 29, cv: "https://my.cv.com/sarah_jones")
let database = StorageDoneDatabase(name: "teachers")

try? database.insert(element: teacher)

Reading database content will retrieve an array of the decleared model

do {
    let savedTeachers: [Teacher] = try database.get()
} catch let e {
    print(e)
}

Other methods allow filtering and deletion.

Primary key

A model can implement PrimaryKey protocol, in order to have an attribute set as database primary key

struct Teacher: Codable, PrimaryKey {
    let id: String
    let name: String?
    let surname: String?
    let age: Int?
    let cv: String?
    
    func primaryKey() -> String {
        return "id"
    }
}

Primary keys come in combination with insert or update methods

let teachers = [Teacher(id: "id1", name: "Sarah", surname: "Jones", age: 29, cv: "https://my.cv.com/sarah_jones"),
                Teacher(id: "id2", name: "Silvia", surname: "Jackson", age: 29, cv: "https://my.cv.com/silvia_jackson"),
                Teacher(id: "id3", name: "John", surname: "Jacobs", age: 30, cv: "https://my.cv.com/john_jackobs")]

try? database.insertOrUpdate(elements: teachers)

RxSwift

Every operation has its RxSwift version. Each can be used through rx extension


database.rx.insertOrUpdate(teachers)

database.rx.insert(teachers)

database.rx.get()

database.rx.get(["id":"id1"])

database.rx.delete(["id":"id2"])

database.rx.deleteAllAndInsert(teachers)

Operators

Database objects can use different custom operators, which wrap try-catch logic and give a more compact way to access database

// Insert or update
database ++= teachers

// Read
let teachers: [Teacher] = <-database

// Filter
let filteredTeachers: [Teacher] = ["id":"id1"] <- database

// Delete if model implements PrimaryKey protocol
database --= teachers

Queries

Get and delete commands can use queries. Queries can be built in different ways, using custom operator or extensions on parameter name


// Equal
"id" *== "id1"
"id".equal("id1")

// Comparison (Numeric only)
"age" *> 20
"age".greaterThan(20)

"age" *>= 20
"age".greaterThanOrEqual(20)

"age" *< 20
"age".lessThan(20)

"age" *<= 20
"age".lessThanOrEqual(20)

"age" <=&&<= (10, 20)
"age".between((10, 20))

// Is nil
*?"name"
"name".isNil

// Is not nil
*!"name"
"name".isNotNil

// Value inside array
"id" |> ["id1", "id2", "id3"]
"id".inside(["id1", "id2", "id3"])

// Array contains value
"array" |< "A1"
"array".contains("A1")

// Like
"name" **= "A%"
"name".like("A%")

// Regex
"city" /== "\\bEng.*e\\b"
"city".regex("\\bEng.*e\\b")

// Dates comparisons
"dateCreated" *> Date()
"dateCreated".greaterThan(Date())

"dateCreated" *>= Date()
"dateCreated".greaterThanOrEqual(Date())

"dateCreated" *< Date()
"dateCreated".lessThan(Date())

"dateCreated" *<= Date()
"dateCreated".lessThanOrEqual(Date())

"dateCreated" <=&&<= (Date().addingTimeInterval(500), Date().addingTimeInterval(1000))

// And
and(expression1, expression2, expression3)

// Or
or(expression1, expression2, expression3)

// Usage
do {
    let teachers: [Teacher] = try database.get(expression)
} catch let e {
    print(e)
}

Live queries

Using live queries it's possible to observe database changes.

// All elements
let liveQuery = try storage.live(Teacher.self) {
    teachers in
        print("Count \(teachers.count)")
}
    
let liveQuery = try storage.live {
    (teachers: [Teacher]) in
        print("Count \(teachers.count)")
}

// Elements with query
let liveQuery = try storage.live(Teacher.self, expression: "id".equal("id1")) {
    teachers in
        print(teachers)
}

let liveQuery = try storage.live("id".equal("id1")) {
    (teachers: [Teacher]) in
        print(teachers)
}

In order to stop observing just call cancel on LiveQuery object.

liveQuery.cancel()

RxSwift live queries

Live queries are also available through RxSwift extensions.

// All elements
let disposable = database.rx.live(Teacher.self).subscribe(onNext: {
    teachers in
    print("Count \(teachers.count)")
})

let disposable = database.rx.live().subscribe(onNext: {
    (teachers: [Teacher]) in
    print("Count \(teachers.count)")
})

// Elements with query
let disposable = database.rx.live(Teacher.self, expression: "id".equal("id1")).subscribe(onNext: {
    teachers in
    print("Count \(teachers.count)")
})

let disposable = database.rx.live("id".equal("id1")).subscribe(onNext: {
    (teachers: [Teacher]) in
    print("Count \(teachers.count)")
})

To stop observing changes just dispose the disposable or alternatively add it to a dispose bag.

disposable.dispose()

// or

disposable.disposed(by: disposeBag)

Advanced queries

Using advanced queries lets to specify filtering expression, ordering logic and priority, limit and skip values.
All of these parameters are optional. The only limitation is that skip is ignored if limit parameter is not present.


try database.get {
    $0.expression = or("id".equal("id1"), "name".equal("Silvia"), "name".equal("John"))
    $0.orderings = ["name".ascending, "date".descending]
    $0.limit = 3
    $0.skip = 2
}

let teachers: [Teacher] = {
    $0.expression = or("id".equal("id1"), "name".equal("Silvia"), "name".equal("John"))
    $0.orderings = ["name".ascending, "date".descending]
    $0.limit = 3
    $0.skip = 2
 } <- databaseCore
 
try database.live({
    $0.expression = or("id".equal("id1"), "name".equal("Silvia"), "name".equal("John"))
    $0.orderings = ["name".ascending, "date".descending]
    $0.limit = 3
    $0.skip = 2
}) {
    (liveTeachers: [Teacher]) in
    print("Count \(liveTeachers.count)")
}

Author

Dario Pellegrini, [email protected]

GitHub