iOS Swift Couchbase Lite Primary Key and Class Configuration - ios

Question

I was going through couchbase-lite to use it in my next iOS app. I have created a model named Surah for now. Definitely, I will have more model classes later.
Basically I have four questions here.
How do I add _id as my primary key in couchbase-lite?
As I will be having more classes how will I handle those? As I am creating
MutableDocument, How will that differentiate each my classes?
As I can see I have to iterate through each of my items to batch insert, won't that become slow for the large datasets?
How do i convert results from a query with large data to a array of Model Class. (in this case of array of Surah)
class Surah: Decodable {
enum Keys: String, CodingKey {
case _id
case index
case englishName
case englishMeaning
case name
case place
case count
}
var _id = ""
var index = 1
var page = 1
var numberOfAyahs = 1
var englishName = ""
var englishMeaning = ""
var name = ""
var place = ""
var isFavorite = false
var dictionary: [String: Any] {
return ["_id": _id, "index": index, "page": page]
}
required init() {}
required init(_id: String, index: Int, name: String, englishName: String, englishMeaning: String, place: String, count: Int) {
self._id = _id
self.index = index
self.name = name
self.englishName = englishName
self.englishMeaning = englishMeaning
self.place = place
self.numberOfAyahs = count
}
required convenience init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: Keys.self) // defining our (keyed) container
let _id: String = try container.decode(String.self, forKey: ._id)
let index: Int = try container.decode(Int.self, forKey: .index)
let name: String = try container.decode(String.self, forKey: .name)
let englishName: String = try container.decode(String.self, forKey: .englishName)
let englishMeaning: String = try container.decode(String.self, forKey: .englishMeaning)
let place: String = try container.decode(String.self, forKey: .place)
let count: Int = try container.decode(Int.self, forKey: .count)
self.init(_id: _id, index: index, name: name, englishName: englishName, englishMeaning: englishMeaning, place: place, count: count)
}}
Code for Database Queries
let surahs = try JSONDecoder().decode([Surah].self, from: data!)
DispatchQueue.global(qos: .background).async {
//background code
do {
if let db = App.shared.database {
try db.inBatch {
for item in surahs {
let doc = MutableDocument(data: item.dictionary)
doc.setString("users", forKey: "type")
doc.setValue(Keys._id, forKey: item._id)
// doc.setValue(Keys.englishName, forKey: item.englishName)
try db.saveDocument(doc)
let index = IndexBuilder.valueIndex(items:
ValueIndexItem.expression(Expression.property("_id")), ValueIndexItem.expression(Expression.property("type")))
try db.createIndex(index, withName: "TypeNameIndex")
print("saved user document \(doc.string(forKey: "englishName"))")
}
}
}
} catch let error {
DispatchQueue.main.async {
seal.reject(error)
}
}
DispatchQueue.main.async {
seal.fulfill(surahs)
}
}

Answer 1

Not sure what you mean by "primary key". You can always find a doc
by its id. The name of the field that contains it is Meta.id.
The field's value is mutableDoc.getId(). As you've noticed, you
can also explicitly set the id at creation
Couchbase doesn't store classes, it stores JSON documents. If you
have documents of different types (different internal structures,
analogous to different SQL tables), give them a type field and use
it in your query
Use Database.inBatch()
The same way you would convert any JSON document to a corresponding
class: gson, Jackson, Moshi, etc