官方档说明：https://realm.io/cn/docs/objc/latest/
安装就按照文档上说的来就可以了
**可以下载个插件 来快速创建model 插件在压缩包里面 文档上也有说明 **
#import <Realm/Realm.h>
@interface Beacons: RLMObject
@property NSString *uuid;
@property NSString * major;
@property NSString *minor;
@end
RLM_ARRAY_TYPE(Beacons)
@interface Wifi : RLMObject
@property NSString *bssid;
@property NSString *ssidname;
@end
RLM_ARRAY_TYPE(Wifi)
@class Mall;
@interface Floor : RLMObject
@property NSString *name;
@property NSString *floor_key;
@property RLMArray<Beacons*><Beacons> *beacons;
@property RLMArray<Wifi*><Wifi> *wifi;
@end
RLM_ARRAY_TYPE(Floor)
@interface Mall : RLMObject
@property NSString *key;
@property NSString *latitude2;
@property NSString *longitude2;
@property RLMArray<Floor*><Floor> *floors;
@end
RLM_ARRAY_TYPE(Mall)
@interface Building : RLMObject
@property NSString *user;
@property NSString *scanTime;
@property NSString *mall_key;
@property Mall *mall;
@property BOOL isSent;
@end
RLM_ARRAY_TYPE(Building)
//添加默认值
@implementation Mall
+ (NSDictionary *)defaultPropertyValues
{
return @{@"latitude2":@"0.0",@"longitude2":@"0.0"};
}
操作方式
[realm beginWriteTransaction];
[realm commitWriteTransaction];
或者 block方式
[realm transactionWithBlock:^{
}];
储存
RLMRealm *realm = [RLMRealm defaultRealm];
Building *building = [[Building alloc]init];
building.user = [AppVariables sharedInstance].user.username;
NSDateFormatter *formatter = [[NSDateFormatter alloc]init];
[formatter setDateFormat:@"yyyy-MM-dd"];
building.scanTime = [formatter stringFromDate:[NSDate date]];
Mall *mall = [[Mall alloc]init];
mall.key = mallkey.key;
mall.longitude2 = [NSString stringWithFormat:@"%f",[AppVariables sharedInstance].dynamicLocation.longitude];
mall.latitude2 = [NSString stringWithFormat:@"%f",[AppVariables sharedInstance].dynamicLocation.latitude];
building.mall_key = mall.key;
building.mall = mall;
[realm transactionWithBlock:^{
[realm addObject:building];
}];
更新
- 找到这个object 然后修改它的属性就可以更新数据了
RLMResults *results = [Building objectsWhere:@"mall_key = %@",self.mall_key];
Building *building = results.firstObject;
RLMResults *queryFloor = [building.mall.floors objectsWhere:@"name = %@",titleMessage];
if (queryFloor.count == 0) {
RLMRealm *realm = [RLMRealm defaultRealm];
NSString *floor_key = [NSUUID UUID].UUIDString;
[realm transactionWithBlock:^{
Floor *floor = [[Floor alloc]init];
floor.floor_key = floor_key;
floor.name = titleMessage;
[building.mall.floors addObject:floor];
}];
}
查询
- 注意查询过后RLMResults不是一个NSArray
- 可以通过
- (RLMObjectType)objectAtIndex:(NSUInteger)index;来获取下标对象
RLMResults *results = [Building objectsWhere:@"mall_key = %@",self.mall_key];
查询所有
[Building allObjects]
删除
[realm beginWriteTransaction];
[realm deleteObject:cheeseBook];
[realm commitWriteTransaction];
或者
[realm transactionWithBlock:^{
[realm deleteObject:cheeseBook];
}];
删除多条数据
[realm beginWriteTransaction];
[realm deleteObjects:[Building allObjects]];
[realm commitWriteTransaction];
删除所有
[realm beginWriteTransaction];
[realm deleteAllObjects];
[realm commitWriteTransaction];
最坑的地方
- 每次更改数据结构的时候都会产生crash 如果在调试的时候还好 可以删除APP 然后重新调试，如果在更新APP的时候需要覆盖安装，我们就需要把数据库迁移
RLMRealmConfiguration *config = [RLMRealmConfiguration defaultConfiguration];
// 设置新的架构版本。这个版本号必须高于之前所用的版本号（如果您之前从未设置过架构版本，那么这个版本号设置为 0）
config.schemaVersion = 1;
// 设置闭包，这个闭包将会在打开低于上面所设置版本号的 Realm 数据库的时候被自动调用
config.migrationBlock = ^(RLMMigration *migration, uint64_t oldSchemaVersion) {
// 目前我们还未进行数据迁移，因此 oldSchemaVersion == 0
if (oldSchemaVersion < 1) {
// 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
}
};
// 告诉 Realm 为默认的 Realm 数据库使用这个新的配置对象
[RLMRealmConfiguration setDefaultConfiguration:config];
// 现在我们已经告诉了 Realm 如何处理架构的变化，打开文件之后将会自动执行迁移
[RLMRealm defaultRealm];
- 如果上面的方法不适合你 可以看看下面的
原模型为
@interface Person : RLMObject
@property NSString *firstName;
@property NSString *lastName;
@property int age;
@end
想变更为 把 firstName 和 lastName 合并在一起
@interface Person : RLMObject
@property NSString *fullName;
@property int age;
@end
RLMRealmConfiguration *config = [RLMRealmConfiguration defaultConfiguration];
// 在 [AppDelegate didFinishLaunchingWithOptions:] 中进行配置RLMRealmConfiguration *config = [RLMRealmConfiguration defaultConfiguration];
config.schemaVersion = 1;
config.migrationBlock = ^(RLMMigration *migration, uint64_t oldSchemaVersion) {
// 目前我们还未进行数据迁移，因此 oldSchemaVersion == 0
if (oldSchemaVersion < 1) {
// enumerateObjects:block: 方法遍历了存储在 Realm 文件中的每一个“Person”对象
[migration enumerateObjects:Person.className block:^(RLMObject *oldObject, RLMObject *newObject) {
// 将名字进行合并，存放在 fullName 域中
newObject[@"fullName"] = [NSString stringWithFormat:@"%@ %@",oldObject[@"firstName"], oldObject[@"lastName"]];
}];
}};
[RLMRealmConfiguration setDefaultConfiguration:config];
