C # how to connect to MySQL with Chinese garbled characters

I suddenly found that all the Chinese characters in my data table were garbled and the English language was normal. I suspected it was a coding problem. In my colleagues' work, I used http to send UTF-8 encoded Chinese characters. The server program can correctly receive and store the characters in the database and read them.

Configure the data table as UTF-8

At first, we thought about the encoding format of the local language and encoded the string, for example;

String str = "Chinese character encoding "; Byte [] bytes = Encoding. UTF8.GetBytes (str ); String newstr = Encoding. UTF8.GetString (bytes );

Subsequent debugging is useless.

Add the following when connecting to the database:

MySQLCommand setformat = new MySQLCommand ("set names gb2312", m_Connection ); Setformat. ExecuteNonQuery (); Setformat. Dispose ();

Done.

At first, I don't know why, because the default configuration of the entire database is UTF-8, and my colleagues correctly executed it when using the http protocol to transmit UTF-8 Chinese characters.

So I looked for the explanation of the set names XX command and found a clear article, which was reproduced.

Recently, we have received BBT training to build a voting system. System code is not very difficult, but I spent most of my time studying character sets and encoding. The encoding (character set) problem between MySQL and Apache makes me suffer. The solution to these problems on the internet is relatively fragmented and one-sided. Most of the solutions are provided, but they do not tell why. So I will summarize the gains over the past few days to avoid future detours. This article is a little helpful for PHP writing (you will know after reading it, how to make your PHP Programs Display normally on servers of most space providers ), however, more help lies in the setup and Setup of network servers.
Let's talk about the character set of MySQL. In Windows, you can modify the [code] # client section in my. ini.

[Mysql]

Default-character-set = utf8

# SERVER SECTION

[Mysqld]

Default-character-set = utf8 [/code] to change the default character set of the database. The first is the default Character Set of the client, and the second is the default Character Set of the server. Suppose we set both to utf8, and then input "show variebles like" character_set _ % ";" in the MySQL Command Line Client. The following characters are displayed:

Character_set_client latin1
Character_set_connection latin1
Character_set_database utf8
Character_set_results latin1
Character_set_server utf8
Character_set_system utf8

The utf8 is changed with the above settings. At this point, if we read data from the database through the PHP program using the UTF-8, it is likely to be a string of Or other garbled characters. After checking the data online for half a day, the solution is simple. After connecting to the database and reading the data, run a query "set names UTF8" first ", [code] mysql_query ("set names UTF8") in PHP; [/code] can be displayed normally (as long as the characters in the database information are normal ). Why? In this query, what is the function of "set names UTF8?
Enter "set names UTF8;" in the MySQL command line, and then execute "show variebles like" character_set _ % ";", the original latin1 variables "character_set_client", "character_set_connection", and "character_set_results" are all changed to utf8. Refer to the Manual. The above sentence is equivalent to: [code] SET character_set_client = utf8;

SET character_set_results = utf8;

SET character_set_connection = utf8; [/code] to check the functions of these three variables:
Information Input path: client → connection → server;
Information output path: server → connection → results.
In other words, each path must undergo three character set encoding changes. Taking garbled output as an example, for utf8 data in the server, the incoming connection is converted to latin1, the incoming results is converted to latin1, And the UTF-8 page is converted to results. If the two character sets are incompatible, such as latin1 and utf8, the conversion process is irreversible and destructive. So it cannot be turned back.
However, we need to declare that "set names UTF8" is only temporary, and the default value will be restored after MySQL is restarted.
Next we will talk about the configuration of MySQL on the server. Isn't it because we have to add "SET NAMESUTF8" to each database read/write to ensure Data Transmission Encoding consistency? Can we configure MySQL to achieve the three variables which are the character set we want by default? I did not mention the manual, and I did not find the answer online. Therefore, the line of code cannot be omitted from the server configuration perspective.

Conclusion: In order to make your webpage display normally on more servers, add "set names UTF8", even if you do not add this sentence.