如何从iOS SQLite数据库中保存和获取数据?

Question

我想从数据库中获取"标签"和"slug"字符串。它们在 init(来自解码器：解码器(中打印得很好，但我可能在保存它们时做错了，因为它们在其他任何地方都消失了。

这是我的解码类

import Foundation
import SQLite
final class AdditionalField : Decodable {
var label : String?
var slug : String?
var data: Any?
var type: QuestionType?
var pollQuestion: PollQuestion?
enum CodingKeys: String, CodingKey {
case label = "label"
case slug = "slug"
}
required init(from row: Row) {
label = row[Columns.label]
slug  = row[Columns.slug]
if let dataString = data as? String, let data = dataString.data(using: .utf8) {
self.data = type?.create(from: data)
}
}
required  init(from decoder: Decoder) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
label = try values.decodeIfPresent(String.self, forKey: .label)
print(label!)
print("label")
slug = try values.decodeIfPresent(String.self, forKey: .slug)
print(slug!)
print("slug")
}
}

extension AdditionalField: SQLTable {
static var tableName = "AdditionalField"
enum Columns {
static let label = Expression<String>("label")
static let slug = Expression<String>("slug")
}

static func createTable(db: Connection) throws {
try db.run(table.create(ifNotExists: true) { table in
table.column(Columns.label)
table.column(Columns.slug)
})
}
static func insert(elements: [AdditionalField]) throws {
try Database.shared.insert(elements: elements)
}
func insert(db: Connection) throws {
try db.run(AdditionalField.table.insert(or: .replace, [
Columns.label <- label ?? "",
Columns.slug  <- slug ?? ""
]))
}
}

我试着这样使用它们。也许这是问题所在？

//   let field = additionalFields?.filter{$0.label == anyTextField.placeholder}.first
// anyTextField.placeholder = field?.label

Answer 1

我创建了一个名为SundeedQLite的库

随意尝试一下！