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爲了建立實體關係,我們將父項Key
(父項關係)或將一個項放入Entity
屬性(子關係)中。GAE數據存儲實體關係
像這樣:
Key resultingKey = KeyFactory.createKey(parent, kind, key);
Entity userEntity = new Entity(resultingKey); // parent
Entity oldAddress = new Entity(KeyFactory.createKey(e.getKey, "Address", userEntity.getOldAddress.getId()));
userEntity.setProperty("oldAddress", oldAddress.getKey()); // child
然而問題是,對於一個主密鑰,並重點應該是數據存儲看跌的產品:
Key resultingKey = _ds.put(parentEntity);
或者創建擁有的KeyFactory密鑰足夠?
此外,這是否也適用於兒童Key
?