如何从mysql结果中读取某些数据C＃ [英] How to read certain data from mysql results in C#

问题描述

我不知道如何在c＃中处理这个问题。我想从C＃

  > con = new MySqlConnection（server = localhost; database = Customers; uid = root; pwd = ******）; 
 con.Open（）; 
 cmd = new MySqlCommand（SELECT name，lastname FROM customer WHERE ID_customer =？Parname;，con）; 
 cmd.Parameters.Add（？Parname，MySqlDbType.Float）.Value = customer_card; 
 cmd.ExecuteNonQuery（）; 
 con.Close（）; 
  

我想能够读取结果，只有一个结果，在2字符串变量。如何获取数据并保存？

谢谢

解决方案

p>对于返回一行的查询，从一个查询中获取多个字符串的快速方法如下：

  con = new MySqlConnection（server = localhost; database = Customers; uid = root; pwd = ******）; 
 try {
 con.Open（）; 
 cmd = new MySqlCommand（SELECT concat（name，'|'，lastname）FROM customer WHERE ID_customer =？Parname;，con）; 
 cmd.Parameters.Add（？Parname，MySqlDbType.Float）.Value = customer_card; //你确定ID是float吗？这是我第一次看到这样的东西！ 
 var tokens =（（String）cmd.ExecuteScalar（））。Split（'|'）; 
 var firstName = tokens [0]; 
 var lastName = tokens [1]; 
 Console.Writeln（First = {0}，Last = {1}，firstName，lastName）; 
} finally {
 con.Close（）; 
} 
  

想法是在MySql端将两个字符串合并成一个，他们回来在C＃侧。这个技巧可以让你避免循环阅读器，关闭它，等等。它假定名称不包含'|'个字符。

I want to make certain query to mysql from C# so I can get back for example name and lastname.

I don't know how to handle this in c# and I want to minimize sqlinjection.

Here is my code:

con = new MySqlConnection("server=localhost;database=Customers;uid=root;pwd=******");
con.Open();
cmd = new MySqlCommand("SELECT name,lastname FROM customer WHERE ID_customer= ?Parname;", con);
cmd.Parameters.Add("?Parname", MySqlDbType.Float).Value = customer_card;
cmd.ExecuteNonQuery();
con.Close();

I want to be able for example to read results and it will be only one result, in the 2 string variables. How to get trough the data and save it?

Thank you

解决方案

A cheating but quick way of getting several strings out of a query returning one row would be as follows:

con = new MySqlConnection("server=localhost;database=Customers;uid=root;pwd=******");
try {
    con.Open();
    cmd = new MySqlCommand("SELECT concat(name,'|',lastname) FROM customer WHERE ID_customer= ?Parname;", con);
    cmd.Parameters.Add("?Parname", MySqlDbType.Float).Value = customer_card; // Are you sure that the ID is float? That's the first time I see anything like that!
    var tokens = ((String)cmd.ExecuteScalar()).Split('|');
    var firstName = tokens[0];
    var lastName = tokens[1];
    Console.Writeln("First={0}, Last={1}", firstName, lastName);
} finally {
    con.Close();
}

The idea is to combine both strings into one on the MySql side, and split them back on the C# side. This trick lets you avoid looping through a reader, closing it, and so on. It assumes that the names do not contain '|' characters.

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