新项目用到了数据库，本来之前用的都是 SQL，但是语法写的实在是恶心，所以使用 Realm 尝试一下。

1、我使用的 pod 库，所以先 pod 库安装一下，安装完别忘了先编译一下，不然 import 不到头文件

platform :ios, '8.0'target 'realmExmple' do  use_frameworks!pod 'RealmSwift'end

 

2、在 AppDelegate 的 didFinishLaunchingWithOptions 中添加如下方法，引入头文件 import RealmSwift

/* Realm 数据库配置，用于数据库的迭代更新 */        let schemaVersion: UInt64 = 0        // 数据库工具类的版本号        SSRealmTool.schemaVersion = schemaVersion                let config = Realm.Configuration(schemaVersion: schemaVersion, migrationBlock: { (migration, oldSchemaVersion) in            /* 什么都不要做！Realm 会自行检测新增和需要移除的属性，然后自动更新硬盘上的数据库架构 */            if (oldSchemaVersion < schemaVersion) {                print("----数据库升级")            }        })                Realm.Configuration.defaultConfiguration = config                Realm.asyncOpen { (realm, error) in            /* Realm 成功打开，迁移已在后台线程中完成 */            if let _ = realm {                print("Realm 数据库配置成功")            } else if let error = error { /* 处理打开 Realm 时所发生的错误 */                print("Realm 数据库配置失败：\(error.localizedDescription)")            }        }

 

3、接下来开始写数据库工具类，新建一个 Swift 文件 SSRealmTool

class SSRealmTool {        /// 数据库版本号    static var schemaVersion: UInt64 = 0        /// 唯一的数据库操作的 Realm    static let ss_realm = realm()        /// 获取数据库操作的 Realm    private static func realm() -> Realm {                // 获取数据库文件路径        let fileURL = URL(string: NSHomeDirectory() + "/Documents/demo.realm")        // 在 APPdelegate 中需要配置版本号时，这里也需要配置版本号        let config = Realm.Configuration(fileURL: fileURL, schemaVersion: schemaVersion)                return try! Realm(configuration: config)    }    }

 

4、新建两个对象 SSDog SSPerson

class SSDog: Object {    // 主键不自增，如果要主键的话，这样写不会有重复的主键//    @objc dynamic var id = NSUUID().UUIDString    // @objc dynamic **必须写    @objc dynamic var name = ""    @objc dynamic var age = 0    @objc dynamic var date = Date()    // 如果需要增加属性的话，只需要在 appdelegate 的版本号加 1 即可自动升级//    @objc dynamic var weight = 1        /// 所属人可选    @objc dynamic var person: SSPerson?        // 设置主键的方法//    override static func primaryKey() -> String? {//        return "id"//    }}

class SSPerson: Object {    @objc dynamic var name = ""    @objc dynamic var age = 0        // 数组使用 List    let dogs = List
     
      ()}
     

5、可以在 viewController 中调用我们的数据库了

 

5.1、添加一个 person

let realm = SSRealmTool.ss_realm                let person = SSPerson()        person.name = "person\(arc4random_uniform(1000))"        person.age = Int(arc4random_uniform(20))                for _ in 0..<9 {                        let dog = SSDog()            dog.name = "dog\(arc4random_uniform(1000))"            dog.age = Int(arc4random_uniform(10))            dog.person = person            person.dogs.append(dog)            print("添加一只狗：\(dog.name),age:\(dog.age),date:\(dog.date)")        }                try! realm.write {            realm.add(person)            print("添加一个人:\(person.name)，年龄:\(person.age)")        }

 

5.2、查询

let realm = SSRealmTool.ss_realm        print("总共有\(realm.objects(SSPerson.self).count)位人")        print("总共有\(realm.objects(SSDog.self).count)只狗")                if realm.objects(SSDog.self).count == 0 || realm.objects(SSPerson.self).count == 0 {            return        }        let dogs = realm.objects(SSDog.self).filter("age <= 5")                for dog in dogs {            print("---查询狗:\(dog.name), age:\(dog.age)，主人是：\(dog.person?.name ?? "无人")")        }                print("---------person---------")                let persons = realm.objects(SSPerson.self).filter("age <= 10")                for person in persons {            print("---查询name:\(person.name), 有\(person.dogs.count)只狗")            print("-----每个人下面的狗-------")            let someDogs = person.dogs.filter("age <= 5")            for someDog in someDogs {                print("---查询狗:\(someDog.name), age:\(someDog.age)，主人是：\(someDog.person?.name ?? "无人")")            }        }

 

5.3、更新

let realm = SSRealmTool.ss_realm                let dogs = realm.objects(SSDog.self).filter("age > 5")                for dog in dogs {                        try! realm.write {                                print("---更新前name:\(dog.name), age:\(dog.age)")                dog.name += "修改"//                realm.add(dog, update: true) // 这需要主键            }        }                let dogs2 = realm.objects(SSDog.self).filter("age > 5")                for dog in dogs2 {            print("---更新后name:\(dog.name), age:\(dog.age)")        }

5.4、删除

let realm = SSRealmTool.ss_realm                let person = SSPerson()        person.name = "person\(arc4random_uniform(1000))"        person.age = Int(arc4random_uniform(20))                for _ in 0..<9 {                        let dog = SSDog()            dog.name = "dog\(arc4random_uniform(1000))"            dog.age = Int(arc4random_uniform(10))            dog.person = person            person.dogs.append(dog)            print("添加一只狗：\(dog.name),age:\(dog.age),date:\(dog.date)")        }                try! realm.write {            realm.add(person)            print("添加一个人:\(person.name)，年龄:\(person.age)")        }