TransactionIsolationLevel Enumeration

 

Specifies the value of the TransactionAttribute.

Namespace:   System.EnterpriseServices
Assembly:  System.EnterpriseServices (in System.EnterpriseServices.dll)

[SerializableAttribute]
public enum TransactionIsolationLevel

Member nameDescription
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.

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
{
}

.NET Framework
Available since 1.1
Return to top
Show: