IsolationLevel 列舉
定義
指定交易的隔離等級 (Isolation Level)。Specifies the isolation level of a transaction.
public enum class IsolationLevelpublic enum IsolationLeveltype IsolationLevel = Public Enum IsolationLevel- 繼承
欄位
| Chaos | 5 | 無法覆寫來自隔離程度更深之交易的暫止變更。The pending changes from more highly isolated transactions cannot be overwritten. |
| ReadCommitted | 2 | 在交易期間無法讀取 Volatile 資料，但可以修改該資料。Volatile data cannot be read during the transaction, but can be modified. |
| ReadUncommitted | 3 | 在交易期間可以讀取和修改 Volatile 資料。Volatile data can be read and modified during the transaction. |
| RepeatableRead | 1 | 在交易期間可以讀取 Volatile 資料，但無法修改該資料。Volatile data can be read but not modified during the transaction. 在交易期間可以加入新資料。New data can be added during the transaction. |
| Serializable | 0 | 在交易期間可以讀取 Volatile 資料，但無法修改該資料，且不能加入新資料。Volatile data can be read but not modified, and no new data can be added during the transaction. |
| Snapshot | 4 | 可以讀取 Volatile 資料。Volatile data can be read. 交易會在修改資料之前，先驗證在最初讀取資料後是否有另一個交易已變更該資料。Before a transaction modifies data, it verifies if another transaction has changed the data after it was initially read. 如果資料已更新，則會引發錯誤，If the data has been updated, an error is raised. 如此可允許交易回到先前所認可的資料值。This allows a transaction to get to the previously committed value of the data. 當您升級使用 |
| Unspecified | 6 | 使用與指定不同的隔離等級，但無法判斷該等級。A different isolation level than the one specified is being used, but the level cannot be determined. 如果設定這個值，會擲回例外狀況。An exception is thrown if this value is set. |
備註
受交易影響的資料稱為 volatile。The data affected by a transaction is called volatile. 當您建立交易時，可以指定套用至交易的隔離等級。When you create a transaction, you can specify the isolation level that applies to the transaction. 交易的隔離等級會決定在交易完成之前, 其他交易對變動性資料有何層級的存取。The isolation level of a transaction determines what level of access other transactions have to volatile data before a transaction completes.
最低隔離等級ReadUncommitted可讓許多交易同時在資料存放區上運作, 並不會因為造成作業中斷交易而造成資料損毀的保護。The lowest isolation level, ReadUncommitted, allows many transactions to operate on a data store simultaneously and provides no protection against data corruption due to interruptive transactions. 最高的隔離等級Serializable會針對造成作業中斷的交易提供高程度的保護, 但必須先完成每筆交易, 然後才允許任何其他交易對資料進行操作。The highest isolation level, Serializable, provides a high degree of protection against interruptive transactions, but requires that each transaction complete before any other transactions are allowed to operate on the data.
交易的隔離等級是在建立交易時決定。The isolation level of a transaction is determined when the transaction is created. 根據預設, System.Transactions基礎結構會Serializable建立交易。By default, the System.Transactions infrastructure creates Serializable transactions. 您可以使用交易的Transaction.IsolationLevel屬性來判斷現有交易的隔離等級。You can determine the isolation level of an existing transaction by using the Transaction.IsolationLevel property of a transaction.