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PHP garbled code problem [Solution]_PHP tutorial
- WBOYOriginal
- 2016-07-13 16:58:401372browse
MySQL "SET NAMES xxx" character set problem analysis
There is also an article about Apache and PHP coding: http://www.phpchina.com/bbs/thread-13860-1-1.html
Recently received training from BBT to build a voting system. The system code is not difficult, but my time is mainly spent on studying character sets and
Encoding above. The encoding (character set) issues of the MySQL and Apache systems made me rack my brains and suffer a lot.
on these issues onlineThe solutions are scattered and one-sided. Most of them provide solutions without explaining why. So I will summarize what I have gained in the past few days to avoid
Latecomers will take detours. This article is a little helpful for PHP writing (after reading it, you will know how to make your PHP program available in most spaces
The provider’s server displays normally), but more help lies in the installation and settings of the network server.
Let’s talk about MySQL’s character set first. Under Windows, you can modify the
in my.ini
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# CLIENT SECTION
[mysql]
default-character-set=utf8
# SERVER SECTION
[mysqld]
default-character-set=utf8
These two fields are used to change the default character set of the database. The first is the client's default character set, and the second is the server's default character set
. Suppose we set both to utf8, and then enter “show variebles like
” in the MySQL Command Line Client"character_set_%";", you can see the following characters:
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 among them changes with our settings above. At this time, if we read data from the database through a PHP program using UTF-8,
It is most likely a string of "?????" or other garbled characters. After searching online for a long time, the solution is simple. After connecting to the database, read
Before fetching data, first execute a query "SET NAMES UTF8", which is
in PHP
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mysql_query("SET NAMES UTF8");
It can be displayed normally (as long as the characters of the information in the database are normal). Why is this happening? What exactly is this query "SET NAMES UTF8"
What does it do?
Go to the MySQL command line and enter "SET NAMES UTF8;", then execute "show variebles like "character_set_%";",
Found those variables "character_set_client", "character_set_connection", and
that were originally latin1The values of "character_set_results" have all changed to utf8. It turns out that these three variables are causing trouble. Check the manual, the above sentence is equal to:
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SET character_set_client = utf8;
SET character_set_results = utf8;
SET character_set_connection = utf8;
Take a look at the functions of these 3 variables:
Information input path: client→connection→server;
Information output path: server→connection→results.
In other words, each path goes through three character set encoding changes. Taking the garbled output as an example, the utf8 data in the server is passed in
The connection is converted to latin1, the incoming results are converted to latin1, and the utf-8 page converts the results again. If the two character sets are not compatible
For example, latin1 and utf8, the conversion process is irreversible and destructive. So it can't be turned back.
But it should be stated here that the effect of "SET NAMES UTF8" is only temporary, and MySQL will return to the default after restarting.
Next, let’s talk about the configuration of MySQL on the server. Don’t we have to add “SET NAMESUTF8” every time we read and write to the database
to ensure consistent encoding of data transmission? Can I configure MySQL so that the three variables default to the character set we want? Hand
It’s not mentioned in the booklet, and I couldn’t find the answer online. Therefore, from a server configuration perspective, there is no way to omit that line of code.
Summary: In order to allow your webpage to display normally on more servers, add "SET NAMES UTF8", even if you don't have it yet
Even if you add this sentence, you can access it normally.