所以我第一次尝试将realm数据库用于我的应用程序。我想在数据库中创建一个关系。
这是json
{
"id": 1,
"name": "Definizioni generali - Doveri nell'uso della strada",
"image": "559",
"video": "0",
"created_at": "2019-03-14 22:27:23",
"updated_at": "2019-03-14 22:27:23",
"sections": [
{
"id": 3110,
"chapter_id": 1,
"name": "a) Definizioni stradali e di traffico",
"created_at": "2019-03-14 22:30:52",
"updated_at": "2019-03-14 22:30:52"
},
{
"id": 3123,
"chapter_id": 1,
"name": "b) Definizioni e classificazione dei veicoli",
"created_at": "2019-03-14 22:30:52",
"updated_at": "2019-03-14 22:30:52"
},
{
"id": 3131,
"chapter_id": 1,
"name": "c) Doveri del conducente nell'uso della strada - Convivenza civile e uso responsabile della strada",
"created_at": "2019-03-14 22:30:52",
"updated_at": "2019-03-14 22:30:52"
},
{
"id": 3137,
"chapter_id": 1,
"name": "d) Riguardo verso gli utenti deboli della strada",
"created_at": "2019-03-14 22:30:52",
"updated_at": "2019-03-14 22:30:52"
}
]
}
这是我的章节课
class Chapter: Object, Mappable {
@objc dynamic var id:Int = -1
@objc dynamic var name: String = kBlankString
@objc dynamic var image: String = kBlankString
@objc dynamic var video: String = kBlankString
@objc dynamic var createdAt: String = kBlankString
@objc dynamic var updatedAt: String = kBlankString
var sections = List<Section>()
override static func primaryKey() -> String? {
return "id"
}
required convenience init?(map: Map) {
self.init()
}
func mapping(map: Map) {
id <- map["id"]
name <- map["name"]
image <- map["image"]
video <- map["video"]
createdAt <- map["created_at"]
updatedAt <- map["updated_at"]
sections <- map["sections"]
}
}
在这条线上sections <- map["sections"]
我添加了断点并检查了po map["sections"].JSON
它在这里显示数据。
问题是章节存储在数据库中,但是每个章节的章节列表都是空的,这是不正确的
这是节类:
class Section: Object, Mappable {
@objc dynamic var id: Int = -1
@objc dynamic var chapterID: Int = -1
@objc dynamic var name: String = kBlankString
@objc dynamic var createdAt: String = kBlankString
@objc dynamic var updatedAt: String = kBlankString
override static func primaryKey() -> String? {
return "id"
}
required convenience init?(map: Map) {
self.init()
}
func mapping(map: Map) {
id <- map["id"]
chapterID <- map["chapter_id"]
name <- map["name"]
createdAt <- map["created_at"]
updatedAt <- map["updated_at"]
}
}
如果我做错了什么,请指导我,这是我第一次尝试使用realm数据库。谢谢
首先,我假设这是使用ObjectMapper(https://github.com/tristanhimmelman/ObjectMapper),我没有使用过它。
但问题是你试图为这些部分做的地图会给你一个数组类型(据我所知),但是Realm不支持数组(正如你所知,因为你正确使用了List
)。
我想你需要一个自定义变换(https://github.com/tristanhimmelman/ObjectMapper#custom-transforms)来转换为List<>
类型。 RealmAdditions展示了如何做到这一点。这显示了在示例代码中执行所需操作的等效行 - 重要的一点是此行(已转换为使用您的类型):
sections <- (map["sections"], ListTransform<Section>())