C#语言向SQL表中插入数据。求解释

            string sql = string.Format("insert into 部门表 values({0},'{1}',{2})",1,'张三',18);
            string conStr=@"Data Source=ONE-TEACHERS\MSSQLSERVER2008;Initial Catalog=数据库;Integrated Security=True";
            SqlConnection conn = new SqlConnection();
            conn.ConnectionString = conStr;
            conn.Open();
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            cmd.CommandText = sql;
          cmd.ExecuteNonQuery();
//新手一个。麻烦大家解释一下上面的程序。帮我一句一句的分析。。。。。。谢谢！

c# sql 数据库
[解决办法]

 //定义字符串变量sql. 赋值要执行的TSQL语句.
 string sql = string.Format("insert into 部门表 values({0},'{1}',{2})",1,'张三',18);

 //定义字符串变量conStr. 赋值连接字符串.
 string conStr=@"Data Source=ONE-TEACHERS\MSSQLSERVER2008;Initial Catalog=数据库;Integrated Security=True";

 //创建SqlConnection对象conn,用于连接数据库.
 SqlConnection conn = new SqlConnection();

 //赋值conStr给conn对象连接字符串属性.
 conn.ConnectionString = conStr;
 
 //conn对象打开连接.
 conn.Open();

 //创建SqlCommand对象cmd.
 SqlCommand cmd = new SqlCommand();

 //指定cmd对象连接属性为conn.
 cmd.Connection = conn;

 //指定cmd对象CommandText属性为sql.
 cmd.CommandText = sql;

 //cmd执行sql语句. 
 cmd.ExecuteNonQuery();