TransactionIsolationLevel 列挙型

  • リファレンス

定義

名前空間:
System.EnterpriseServices
アセンブリ:
System.EnterpriseServices.dll

TransactionAttribute の値を指定します。

public enum class TransactionIsolationLevel
[System.Serializable]
public enum TransactionIsolationLevel
[<System.Serializable>]
type TransactionIsolationLevel = 
Public Enum TransactionIsolationLevel
継承
Object
ValueType
Enum
TransactionIsolationLevel
属性
SerializableAttribute

フィールド

Any 0

コンポーネントの分離レベルは、呼び出し元コンポーネントの分離レベルから取得します。 ルート コンポーネントの場合、使用される分離レベルは Serializable です。
ReadCommitted 2

データの読み取り中は、変更されたデータが読み取られることを避けるために、共有ロックが設定されます。しかし、トランザクションの終了前にデータが変更されることもあるため、反復不能読み取りやファントム データが発生する可能性があります。
ReadUncommitted 1

共有ロックが発行されるため、排他ロックは受け入れられません。
RepeatableRead 3

他のユーザーがデータを更新できないようにするために、クエリで使用するすべてのデータをロックします。 反復不能読み取りは回避できますが、ファントム行が発生する可能性はあります。
Serializable 4

トランザクション完了前の更新または挿入を防止します。

例

次のコード例では、 型の使用方法を TransactionIsolationLevel 示します。

#using <System.EnterpriseServices.dll>

using namespace System;
using namespace System::EnterpriseServices;
using namespace System::Reflection;

// References:
// System.EnterpriseServices

// An instance of this class will inherit its caller's transaction isolation
// level if available. If not, it will use isolation level Serializable.
[Transaction(Isolation=TransactionIsolationLevel::Any)]
public ref class IsolationAny : public ServicedComponent
{
};

// An instance of this class will read only committed data, but non-repeatable
// reads and phantom rows are still possible.
[Transaction(Isolation=TransactionIsolationLevel::ReadCommitted)]
public ref class IsolationReadCommitted : public ServicedComponent
{
};

// An instance of this class will read committed and uncommitted data, so dirty
// reads, non-repeatable reads, and phantom rows are possible.
[Transaction(Isolation=TransactionIsolationLevel::ReadUncommitted)]
public ref class IsolationReadUncommitted : public ServicedComponent
{
};

// An instance of this class will read only committed data and place shared
// locks on the data, preventing other users from modifying it, but other users
// can still insert rows into the data set, so phantom rows are still possible.
[Transaction(Isolation=TransactionIsolationLevel::RepeatableRead)]
public ref class IsolationRepeatableRead : public ServicedComponent
{
};

// An instance of this class will read only committed data and place a range
// lock on the data set, preventing other users from updating or inserting rows
// into the data set until its transaction is complete.
[Transaction(Isolation=TransactionIsolationLevel::Serializable)]
public ref class IsolationSerializable : public ServicedComponent
{
};

using System;
using System.EnterpriseServices;
using System.Reflection;

// References:
// System.EnterpriseServices

// An instance of this class will inherit its caller's transaction isolation
// level if available. If not, it will use isolation level Serializable.
[Transaction(Isolation=TransactionIsolationLevel.Any)]
public class TransactionAttribute_IsolationAny : ServicedComponent
{
}

// An instance of this class will read only committed data, but non-repeatable
// reads and phantom rows are still possible.
[Transaction(Isolation=TransactionIsolationLevel.ReadCommitted)]
public class TransactionAttribute_IsolationReadCommitted : ServicedComponent
{
}

// An instance of this class will read committed and uncommitted data, so dirty
// reads, non-repeatable reads, and phantom rows are possible.
[Transaction(Isolation=TransactionIsolationLevel.ReadUncommitted)]
public class TransactionAttribute_IsolationReadUncommitted : ServicedComponent
{
}

// An instance of this class will read only committed data and place shared
// locks on the data, preventing other users from modifying it, but other users
// can still insert rows into the data set, so phantom rows are still possible.
[Transaction(Isolation=TransactionIsolationLevel.RepeatableRead)]
public class TransactionAttribute_IsolationRepeatableRead : ServicedComponent
{
}

// An instance of this class will read only committed data and place a range
// lock on the data set, preventing other users from updating or inserting rows
// into the data set until its transaction is complete.
[Transaction(Isolation=TransactionIsolationLevel.Serializable)]
public class TransactionAttribute_IsolationSerializable : ServicedComponent
{
}

Imports System.EnterpriseServices
Imports System.Reflection


' References:
' System.EnterpriseServices

' An instance of this class will inherit its caller's transaction isolation
' level if available. If not, it will use isolation level Serializable.
<Transaction(Isolation := TransactionIsolationLevel.Any)>  _
Public Class TransactionAttribute_IsolationAny
    Inherits ServicedComponent
End Class

' An instance of this class will read only committed data, but non-repeatable
' reads and phantom rows are still possible.
<Transaction(Isolation := TransactionIsolationLevel.ReadCommitted)>  _
Public Class TransactionAttribute_IsolationReadCommitted
    Inherits ServicedComponent
End Class

' An instance of this class will read committed and uncommitted data, so dirty
' reads, non-repeatable reads, and phantom rows are possible.
<Transaction(Isolation := TransactionIsolationLevel.ReadUncommitted)>  _
Public Class TransactionAttribute_IsolationReadUncommitted
    Inherits ServicedComponent
End Class

' An instance of this class will read only committed data and place shared
' locks on the data, preventing other users from modifying it, but other users
' can still insert rows into the data set, so phantom rows are still possible.
<Transaction(Isolation := TransactionIsolationLevel.RepeatableRead)>  _
Public Class TransactionAttribute_IsolationRepeatableRead
    Inherits ServicedComponent
End Class

' An instance of this class will read only committed data and place a range
' lock on the data set, preventing other users from updating or inserting rows
' into the data set until its transaction is complete.
<Transaction(Isolation := TransactionIsolationLevel.Serializable)>  _
Public Class TransactionAttribute_IsolationSerializable
    Inherits ServicedComponent
End Class

適用対象