领域主键迁移 - 目标C

Question

旧RLMObject位于下方，primaryKey是AttributeId。我想将此密钥更改为@＆＃34; Id＆＃34;下一次建设。

UserItemObject.m

MC_choice

UserItemObject.h

@implementation UserItemObject {

}

+ ( NSString * )primaryKey; {
    return @"AttributeId";
}

@end

然后我给AppDelegate写了一些代码;

@interface UserItemObject : RLMObject
   @property(nonatomic, copy) NSString *Id;
   @property(nonatomic, copy) NSString *AttributeId;
@end
RLM_ARRAY_TYPE(UserItemObject)

此代码给我一个错误;

  [RLMRealm setSchemaVersion:1 forRealmAtPath:[RLMRealm defaultRealmPath] withMigrationBlock:^(RLMMigration *migration, NSUInteger oldSchemaVersion) {
      if ( oldSchemaVersion < 1 ) {
          [migration enumerateObjects: UserItemObject.className block:^(RLMObject *oldObject, RLMObject *newObject) {
                newObject[ @"primaryKeyProperty" ] = @"Id";
          }];
      }
  }];

我该如何解决这个问题？非常感谢。

Answer 1

要更改主键属性，您需要更改+[UserItemObject primaryKey]的返回值。

然后，要实际进行迁移，您将执行以下操作：

[RLMRealm setSchemaVersion:1 forRealmAtPath:[RLMRealm defaultRealmPath] withMigrationBlock:^(RLMMigration *migration, NSUInteger oldSchemaVersion) {
      if ( oldSchemaVersion < 1 ) {
          [migration enumerateObjects: UserItemObject.className block:^(RLMObject *oldObject, RLMObject *newObject) {
                newObject[ @"Id" ] = oldObject[@"AttributeId"];
          }];
      }
  }];