Question

我正在努力将Core Data实体迁移到Realm。实体中可能有超过200万条记录，所以我希望尽可能高效地完成这项工作。

迁移分批处理10000条记录，以下是我用来执行此操作的代码：

/// We're in a loop
/// Get the 10000 records out of Core Data
[realm beginWriteTransaction];
// samples is an NSArray of NSManagedObjects
NSInteger numberOfSamples = samples.count;
for (NSInteger i = 0; i < numberOfSamples; i++)
{
    // WeightSample is an NSManagedObject
    WeightSample *sample = samples[i];

    //Diagnostic is an RLMObject
    Diagnostic *weightSample = [Diagnostic new];

    ///
    /// transfer data from WeightSample to Diagnostic
    ///

    [realm addObject:weightSample];

    // Remove the old sample from Core Data
    [context deleteObject:sample];
}
[realm commitWriteTransaction];

/// Start over at the top of the loop

我是否会在[context deleteObject:sample]区块内遇到beginWriteTransaction-commitWriteTransaction的任何问题？

根据我神秘的tweet @Realm和他们的回复，我的假设是“不，但我会阻止更长时间”。

我可以将其卸载到另一个帖子，对吗？

Answer 1

我做过类似于Realm的事情，但是，在我的情况下，我发现在迁移完成后删除所有核心数据sqlite文件，最快/最有效。我假设迁移完成后你不需要你的核心数据存储，所以，我就是这样做的。

/// We're in a loop
/// Get the 10000 records out of Core Data
[realm beginWriteTransaction];
// samples is an NSArray of NSManagedObjects
// WeightSample is an NSManagedObject
for (WeightSample *sample in samples)
{
    //Diagnostic is an RLMObject
    Diagnostic *weightSample = [Diagnostic new];

    ///
    /// transfer data from WeightSample to Diagnostic
    ///

    [realm addObject:weightSample];
}
[realm commitWriteTransaction];

/// Start over at the top of the loop

/// After all the data has been transferred to realm, delete all core-data sqlite files using NSFileManager API.

删除领域写入事务块中的核心数据对象？

1 个答案: