TransactionScope和Enterprise Libray 3.0 Data Access Application Block

Enterprise Libray 3.0已经发布了,具体可参见TerryLeeEnterprise Library 3.0 发布.下载了看看,有非常激动人心的更新.我只是看看Data Access Application Block代码,代码中有这个类TransactionScopeConnections,是个内部类,设计意图很明显就是使用数据库的事务模型.我觉得设计为内部类有点瑕疵,我的习惯是事务和提交在业务逻辑层. .NET 2.0的System.Transactions应该是一个更好的选择。就将Data Access Application Block的QuickStart例子代码:

/// <summary>
/// Transfers an amount between two accounts.
/// </summary>
/// <param name="transactionAmount">Amount to transfer.</param>
/// <param name="sourceAccount">Account to be credited.</param>
/// <param name="destinationAccount">Account to be debited.</param>
/// <returns>true if sucessful; otherwise false.</returns>
/// <remarks>Demonstrates executing multiple updates within the
/// context of a transaction.</remarks>
public bool Transfer(int transactionAmount,int sourceAccount,int destinationAccount)
{
bool result = false;

// Create the Database object,using the default database service. The
// default database service is determined through configuration.
Database db = DatabaseFactory.CreateDatabase();

// Two operations,one to credit an account,and one to debit another
// account.
string sqlCommand = "CreditAccount"
DbCommand creditCommand = db.GetStoredProcCommand(sqlCommand);

db.AddInParameter(creditCommand,"AccountID",DbType.Int32,sourceAccount);
db.AddInParameter(creditCommand,"Amount",transactionAmount);

sqlCommand = "DebitAccount"
DbCommand debitCommand = db.GetStoredProcCommand(sqlCommand);

db.AddInParameter(debitCommand,destinationAccount);
db.AddInParameter(debitCommand,transactionAmount);

using (DbConnection connection = db.CreateConnection())
{
connection.Open();
DbTransaction transaction = connection.BeginTransaction();

try
{
// Credit the first account
db.ExecuteNonQuery(creditCommand,transaction);
// Debit the second account
db.ExecuteNonQuery(debitCommand,transaction);

// Commit the transaction
transaction.Commit();

result = true;
}
catch
{
// Rollback transaction
transaction.Rollback();
}
connection.Close();

return result;
}
}

按照TransactionScope类进行改造,试验成功了,代码如下:

public bool Transfer(int transactionAmount,int destinationAccount)
{
bool result = false;
Database database = DatabaseFactory.CreateDatabase();

using (TransactionScope scope = new TransactionScope(TransactionScopeOption.RequiresNew))
{
TestCommand1(database,transactionAmount,sourceAccount);
TestCommand2(database,destinationAccount);
scope.Complete();
result = true;
}
return result;

}

private void TestCommand1(Database db,int transactionAmount,int sourceAccount)
{
string sqlCommand = "CreditAccount"
DbCommand creditCommand = db.GetStoredProcCommand(sqlCommand);

db.AddInParameter(creditCommand,transactionAmount);

// Credit the first account
db.ExecuteNonQuery(creditCommand);
}

private void TestCommand2(Database db,int destinationAccount)
{
string sqlCommand = "DebitAccount"
DbCommand debitCommand = db.GetStoredProcCommand(sqlCommand);

db.AddInParameter(debitCommand,transactionAmount);

// Debit the second account
db.ExecuteNonQuery(debitCommand);
}

  DAAB  在一个事务中可以在一个数据库连接中检测到几个命令的执行,这样可以避免虽然一个数据库连接执行的几个命令而启用 分布式事务 。在企业类库2.0的DAAB常常启用了分布式事务,就凭这一点,使用企业类库2.0的同学们有必要升级到企业类库3.0。

Parameter Discovery on Ms Access and SqlServer. using Microsoft Patterns and Practices DataBlock version 3.0 final
http://www.codeproject.com/useritems/Parameter_DiscoveryV292.asp

相关文章

本篇内容主要讲解“sqlalchemy的常用数据类型怎么使用”,感...
今天小编给大家分享一下sqlServer实现分页查询的方式有哪些的...
这篇文章主要介绍“sqlmap之osshell怎么使用”,在日常操作中...
本篇内容介绍了“SQL注入的知识点有哪些”的有关知识,在实际...
1. mssql权限sa权限:数据库操作,文件管理,命令执行,注册...
sql执行计划如何查看?在SPL庞大的数据中我们不知道如何查看...