我目前在一层中有两个类,它们将数据包含在数据库中:
using Dapper;
using System;
using System.Data.SqlClient;
using System.Linq;
namespace repositories
{
public class DAOBook
{
private readonly string _connection;
public DAOBook(string databaseConnection)
{
_connection = databaseConnection;
}
public bool IncludeBook(string title)
{
try
{
using (var connection = new SqlConnection(_connection))
{
var sql = $@"
INSERT INTO books
(title)
VALUES
('{title}' ";
var result = connection.Execute(sql);
return result != 0;
}
}
catch (Exception ex)
{
throw new Exception($"{ex.Message}", ex);
}
}
}
}
using Dapper;
using System;
using System.Data.SqlClient;
using System.Linq;
namespace repositories
{
public class DAOBookTag
{
private readonly string _connection;
public DAOBookTag(string databaseConnection)
{
_connection = databaseConnection;
}
public bool IncludeBookTag(string tag, int userid)
{
try
{
using (var connection = new SqlConnection(_connection))
{
var sql = $@"
INSERT INTO bookTag
(tag, userid)
VALUES
('{tag}', {userid} ";
var result = connection.Execute(sql);
return result != 0;
}
}
catch (Exception ex)
{
throw new Exception($"{ex.Message}", ex);
}
}
}
}
在我的服务层中,我可以正常调用这两个类,然后将它们插入数据库。
try
{
var connectionString = "<my_connection_string>";
var daoBook = new DAOBook(connectionString);
var daoBookTag = new DAOBookTag(connectionString);
dao.IncludeBook("Alice");
dao.IncludeBookTag("Romance", 1);
}
catch (Exception ex)
{
throw new Exception($"{ex.Message}", ex);
}
但是,我想放置一个事务控件,以便在第二类的插入发生错误的情况下,它会取消catch中的事务,如下所示:
try
{
var connectionString = "<my_connection_string>";
var daoBook = new DAOBook(connectionString);
var daoBookTag = new DAOBookTag(connectionString);
// begin transaction
dao.IncludeBook("Alice");
dao.IncludeBookTag("Romance", 1);
// commit
}
catch (Exception ex)
{
// rollback
throw new Exception($"{ex.Message}", ex);
}
我知道这一定是一个初学者的问题,但是我似乎找不到两个持久化类共享同一事务的方法。
我看到了实现Dapper事务控制的示例,但是我不知道如何在服务层(而不是持久层)中实现它。https://riptutorial.com/dapper/example/22536/using-a-transaction
谢谢
using (var transactionScope = new TransactionScope())
{
var connectionString = "<my_connection_string>";
var daoBook = new DAOBook(connectionString);
var daoBookTag = new DAOBookTag(connectionString);
// begin transaction
dao.IncludeBook("Alice");
dao.IncludeBookTag("Romance", 1);
//commit
transactionScope.Complete();
}
[在ADO.NET中有两种处理事务的方法;通常首选的机制是ADO.NET事务,即BeginTransaction
。这有局限性,但效率很高,并且可以本地映射到大多数提供程序。 ADO.NET事务的关键限制是它仅跨越一个连接,并且您的连接必须至少持续与事务一样长的时间。
就Dapper的使用而言,您还必须将事务into]传递给调用;例如:
using (var conn = new SqlConnection(connectionString)) { connection.Open(); using (var tran = connection.BeginTransaction()) { // ... your work tran.Commit(); } }
这里“您的工作”有效地使用相同的
conn
和tran
实例,使用:
方法是使用var result = conn.Execute(sql, args, transaction: tran);
lazyer
TransactionScope
。使用起来比较简单,但是更多参与。我通常不建议这样做,但是它可以工作。您还应该参数化:
var sql = @"
INSERT INTO bookTag (tag, userid)
VALUES (@tag, @userId)";
var result = connection.Execute(sql, new { tag, userId });