如何从 asmx Web 服务管理多个 ado.net 数据库连接

发布于 2024-08-12 05:55:38 字数 556 浏览 0 评论 0原文

由于 IIS 为每个请求分配一个工作线程，因此我打算创建新对象来服务每个请求。我有两个问题：

创建新对象来服务每个请求是否有效？（甚至还有替代方案吗？）
创建新连接并为每个请求打开和关闭它是否是线程安全、高效和最佳实践，如下所示：

using (MySqlConnection conn = new MySqlConnection(ConfigurationManager.ConnectionStrings["MySqlConnectionString"].ConnectionString))
{ 
    conn.Open();
    MySqlCommand cmd = new MySqlCommand("SELECT password FROM Admin WHERE username='" + username + "'", conn);
    object dbp = cmd.ExecuteScalar();
    conn.Close();
}

PS。这个例子取自这个网站。我用的是oracle数据库。

谢谢：马蒂

原文

Since IIS assigns a worker thread for each request I've intention to create new object to serve each request. I have 2 questions:

Is it efficient to create new object to serve each request? (is there even alternatice?)
Is it thread safe, efficient and best practice to create new connection, and open&close it for each request like below:

using (MySqlConnection conn = new MySqlConnection(ConfigurationManager.ConnectionStrings["MySqlConnectionString"].ConnectionString))
{ 
    conn.Open();
    MySqlCommand cmd = new MySqlCommand("SELECT password FROM Admin WHERE username='" + username + "'", conn);
    object dbp = cmd.ExecuteScalar();
    conn.Close();
}

PS. this example is taken from this site. I use oracle db.

Thanks: Matti

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江挽川 2024-08-19 05:55:38

当您执行 new SomeSqlConnection() 时，您实际上并不是每次都创建一个新连接。由于创建数据库连接的成本很高，ADO.NET 保留一个连接池并从那里提取连接。您还可以删除对 Close 方法的调用。以下是您可以在每个请求中安全使用的代码片段：

var connectionString = ConfigurationManager.ConnectionStrings["MySqlConnectionString"].ConnectionString;
using (var conn = new MySqlConnection(connectionString))
using (var cmd = conn.CreateCommand())
{ 
    conn.Open();
    cmd.CommandText = "SELECT count(*) from some_table";
    object result = cmd.ExecuteScalar();
}

When you do new SomeSqlConnection() you actually don't create a new connection every time. As database connections are expensive to create ADO.NET keeps a connection pool and draws connections from there. You could also remove the call to the Close method. Here's a snippet you can safely use in each request:

var connectionString = ConfigurationManager.ConnectionStrings["MySqlConnectionString"].ConnectionString;
using (var conn = new MySqlConnection(connectionString))
using (var cmd = conn.CreateCommand())
{ 
    conn.Open();
    cmd.CommandText = "SELECT count(*) from some_table";
    object result = cmd.ExecuteScalar();
}

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