您能够在迁移期间创建领域对象吗?我想要提取现有领域对象的一部分并使用该数据创建一个新对象,但迁移总是挂起。这是我的迁移代码
private class var migrationBlock: MigrationBlock {
return { migration, oldSchemaVersion in
if oldSchemaVersion < 1 {
print("Shema Version 0")
migration.enumerate(Transaction.className(), { (oldObject, newObject) -> Void in
let oldDate = oldObject!["date"] as! NSDate
let newTransactionDate = TransactionDate()
newTransactionDate.date = oldDate
try! Realm.getRealm().write { Realm.getRealm().add(newTransactionDate, update: true) }
newObject!["_date"] = newTransactionDate
})
}
}
}
您可以使用Migration.create(_:value:)
在迁移期间创建对象。
https://realm.io/docs/swift/latest/api/Classes/Migration.html#/s:FC10RealmSwift9Migration6createFS0_FTSS5valuePSs9AnyObject__CS_13DynamicObject https://realm.io/docs/swift/latest/api/Classes/Migration.html#/s:FC10RealmSwift9Migration6createFS0_FTSS5valuePSs9AnyObject__CS_13DynamicObject
它返回MigrationObject
的实例。因此,您应该使用下标为其属性赋值。
let oldDate = oldObject!["date"] as! NSDate
let newTransactionDate = migration.create(TransactionDate.className())
newTransactionDate["date"] = oldDate
newObject!["_date"] = newTransactionDate
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