TransactionIsolationLevel Enumeration
.NET Framework 2.0
Specifies the value of the TransactionAttribute.
Namespace: System.EnterpriseServices
Assembly: System.EnterpriseServices (in system.enterpriseservices.dll)
Assembly: System.EnterpriseServices (in system.enterpriseservices.dll)
| Member name | Description | |
|---|---|---|
| Any | The isolation level for the component is obtained from the calling component's isolation level. If this is the root component, the isolation level used is Serializable. | |
| ReadCommitted | Shared locks are held while the data is being read to avoid reading modified data, but the data can be changed before the end of the transaction, resulting in non-repeatable reads or phantom data. | |
| ReadUncommitted | Shared locks are issued and no exclusive locks are honored. | |
| RepeatableRead | Locks are placed on all data that is used in a query, preventing other users from updating the data. Prevents non-repeatable reads, but phantom rows are still possible. | |
| Serializable | Prevents updating or inserting until the transaction is complete. |
The following code example demonstrates the use of the TransactionIsolationLevel type.
Imports System 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 'TransactionAttribute_IsolationAny ' 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 'TransactionAttribute_IsolationReadCommitted ' 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 'TransactionAttribute_IsolationReadUncommitted ' 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 'TransactionAttribute_IsolationRepeatableRead ' 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 'TransactionAttribute_IsolationSerializable
import System.*;
import System.EnterpriseServices.*;
import 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.
/** @attribute Transaction(Isolation = TransactionIsolationLevel.Any)
*/
public class TransactionAttribute_IsolationAny extends ServicedComponent
{
} //TransactionAttribute_IsolationAny
// An instance of this class will read only committed data, but non-repeatable
// reads and phantom rows are still possible.
/** @attribute Transaction(Isolation = TransactionIsolationLevel.ReadCommitted)
*/
public class TransactionAttribute_IsolationReadCommitted
extends ServicedComponent
{
} //TransactionAttribute_IsolationReadCommitted
// An instance of this class will read committed and uncommitted data, so dirty
// reads, non-repeatable reads, and phantom rows are possible.
/** @attribute Transaction(Isolation = TransactionIsolationLevel.
ReadUncommitted)
*/
public class TransactionAttribute_IsolationReadUncommitted
extends ServicedComponent
{
} //TransactionAttribute_IsolationReadUncommitted
// 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.
/** @attribute Transaction(Isolation = TransactionIsolationLevel.
RepeatableRead)
*/
public class TransactionAttribute_IsolationRepeatableRead
extends ServicedComponent
{
} //TransactionAttribute_IsolationRepeatableRead
// 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.
/** @attribute Transaction(Isolation = TransactionIsolationLevel.Serializable)
*/
public class TransactionAttribute_IsolationSerializable
extends ServicedComponent
{
} //TransactionAttribute_IsolationSerializable
Windows 98, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.
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