I tried to use UTF-8 and ran into trouble.
I have tried so many things; here are the results I have gotten:
???? instead of Asian characters. Even for European text, I got Se?or for Señor.
Strange gibberish (Mojibake?) such as Señor or 新浪新闻 for 新浪新闻.
Black diamonds, such as Se�or.
Finally, I got into a situation where the data was lost, or at least truncated: Se for Señor.
Even when I got text to look right, it did not sort correctly.
What am I doing wrong? How can I fix the code? Can I recover the data, if so, how?
This problem plagues the participants of this site, and many others.
You have listed the five main cases of CHARACTER SET troubles.
Best Practice
Going forward, it is best to use CHARACTER SET utf8mb4 and COLLATION utf8mb4_unicode_520_ci. (There is a newer version of the Unicode collation in the pipeline.)
utf8mb4 is a superset of utf8 in that it handles 4-byte utf8 codes, which are needed by Emoji and some of Chinese.
Outside of MySQL, "UTF-8" refers to all size encodings, hence effectively the same as MySQL's utf8mb4, not utf8.
I will try to use those spellings and capitalizations to distinguish inside versus outside MySQL in the following.
Overview of what you should do
Have your editor, etc. set to UTF-8.
HTML forms should start like <form accept-charset="UTF-8">.
Have your bytes encoded as UTF-8.
Establish UTF-8 as the encoding being used in the client.
Have the column/table declared CHARACTER SET utf8mb4 (Check with SHOW CREATE TABLE.)
<meta charset=UTF-8> at the beginning of HTML
Stored Routines acquire the current charset/collation. They may need rebuilding.
UTF-8 all the way through
More details for computer languages (and its following sections)
Test the data
Viewing the data with a tool or with SELECT cannot be trusted.
Too many such clients, especially browsers, try to compensate for incorrect encodings, and show you correct text even if the database is mangled.
So, pick a table and column that has some non-English text and do
SELECT col, HEX(col) FROM tbl WHERE ...
The HEX for correctly stored UTF-8 will be
For a blank space (in any language): 20
For English: 4x, 5x, 6x, or 7x
For most of Western Europe, accented letters should be Cxyy
Cyrillic, Hebrew, and Farsi/Arabic: Dxyy
Most of Asia: Exyyzz
Emoji and some of Chinese: F0yyzzww
More details
Specific causes and fixes of the problems seen
Truncated text (Se for Señor):
The bytes to be stored are not encoded as utf8mb4. Fix this.
Also, check that the connection during reading is UTF-8.
Black Diamonds with question marks (Se�or for Señor);
one of these cases exists:
Case 1 (original bytes were not UTF-8):
The bytes to be stored are not encoded as utf8. Fix this.
The connection (or SET NAMES) for the INSERT and the SELECT was not utf8/utf8mb4. Fix this.
Also, check that the column in the database is CHARACTER SET utf8 (or utf8mb4).
Case 2 (original bytes were UTF-8):
The connection (or SET NAMES) for the SELECT was not utf8/utf8mb4. Fix this.
Also, check that the column in the database is CHARACTER SET utf8 (or utf8mb4).
Black diamonds occur only when the browser is set to <meta charset=UTF-8>.
Question Marks (regular ones, not black diamonds) (Se?or for Señor):
The bytes to be stored are not encoded as utf8/utf8mb4. Fix this.
The column in the database is not CHARACTER SET utf8 (or utf8mb4). Fix this. (Use SHOW CREATE TABLE.)
Also, check that the connection during reading is UTF-8.
Mojibake (Señor for Señor):
(This discussion also applies to Double Encoding, which is not necessarily visible.)
The bytes to be stored need to be UTF-8-encoded. Fix this.
The connection when INSERTing and SELECTing text needs to specify utf8 or utf8mb4. Fix this.
The column needs to be declared CHARACTER SET utf8 (or utf8mb4). Fix this.
HTML should start with <meta charset=UTF-8>.
If the data looks correct, but won't sort correctly, then
either you have picked the wrong collation,
or there is no collation that suits your need,
or you have Double Encoding.
Double Encoding can be confirmed by doing the SELECT .. HEX .. described above.
é should come back C3A9, but instead shows C383C2A9
The Emoji 👽 should come back F09F91BD, but comes back C3B0C5B8E28098C2BD
That is, the hex is about twice as long as it should be.
This is caused by converting from latin1 (or whatever) to utf8, then treating those
bytes as if they were latin1 and repeating the conversion.
The sorting (and comparing) does not work correctly because it is, for example,
sorting as if the string were Señor.
Fixing the Data, where possible
For Truncation and Question Marks, the data is lost.
For Mojibake / Double Encoding, ...
For Black Diamonds, ...
The Fixes are listed here. (5 different fixes for 5 different situations; pick carefully): http://mysql.rjweb.org/doc.php/charcoll#fixes_for_various_cases
I had similar issues with two of my projects, after a server migration. After searching and trying a lot of solutions, I came across with this one:
mysqli_set_charset($con,"utf8mb4");
After adding this line to my configuration file, everything works fine!
I found this solution for MySQLi—PHP mysqli set_charset() Function—when I was looking to solve an insert from an HTML query.
I was also searching for the same issue. It took me nearly one month to find the appropriate solution.
First of all, you will have to update you database will all the recent CHARACTER and COLLATION to utf8mb4 or at least which support UTF-8 data.
For Java:
while making a JDBC connection, add this to the connection URL useUnicode=yes&characterEncoding=UTF-8 as parameters and it will work.
For Python:
Before querying into the database, try enforcing this over the cursor
cursor.execute('SET NAMES utf8mb4')
cursor.execute("SET CHARACTER SET utf8mb4")
cursor.execute("SET character_set_connection=utf8mb4")
If it does not work, happy hunting for the right solution.
Set your code IDE language to UTF-8
Add <meta charset="utf-8"> to your webpage header where you collect data form.
Check your MySQL table definition looks like this:
CREATE TABLE your_table (
...
) ENGINE=InnoDB DEFAULT CHARSET=utf8
If you are using PDO, make sure
$options = array(PDO::MYSQL_ATTR_INIT_COMMAND=>'SET NAMES utf8');
$dbL = new PDO($pdo, $user, $pass, $options);
If you already got a large database with above problem, you can try SIDU to export with correct charset, and import back with UTF-8.
Depending on how the server is setup, you have to change the encode accordingly. utf8 from what you said should work the best. However, if you're getting weird characters, it might help if you change the webpage encoding to ANSI.
This helped me when I was setting up a PHP MySQLi. This might help you understand more: ANSI to UTF-8 in Notepad++
I'm Vietnamese, I used to use some Unicode character ex 'Việt Nam', â, ẵ, ấ, ị, đ, Đ, Ệ, Ố, ư..., I'm having a exercise relate with insert/receive data from database, I'm using Java. I can not receive data from database without many error with there character. Who can help me ?
It whould be better to understand your problem with the exact error code. But as I underestand you, your problem is that you have something in database ( and it's okthere ) but when you want to read and show it, you face with some problems. With these background I think:
you have to use utf-8 to store and read data.
your application have to support your locale. ( for instance as I know JDK doesn't support fa_IR locale, so it may be your problem)
But as there are lots of vietnamians java application, your problem should belongs to your DAL.
Provide complete error and ensure that your data is stored correctly in your database.
Try Java 7 if you want to use Access database.
Otherwise, use a different DBMS that Java currently supports queries or updates with Unicode characters.
Java Programming with Vietnamese
I am reading a column from database using rs.getString() method , the column has some multibyte data.
When retrieved through rs.getString() , the data get garbled and all multibyte characters appear as ??????.
Please suggest what should be done.
I have tried using -Dfile.encoding=UTF8 , but that does not work out.
Do you have the language sets installed on the machine you are trying to decode? Can you get the data out correctly using any methods?
how to read unicode text from java resultset?
rs.getString() returns a Java String which is Unicode by definition.
If you get mangled characters, you have to configure your database driver to use the right encoding for the connection to the database.
Just read the strings. All strings in Java are unicode already. If you're having problems, then:
It could be a diagnostic problem - you may be reading the right data out of the ResultSet but displaying it so it looks like you haven't read it properly
It could be a configuration problem - there may be something you need to do when connecting to the database so that it determines the right encoding to use
It could be a database problem - the database may not be configured to store full Unicode data
It could be a database schema problem - the particular column you're using may be configured using a column type which doesn't support full Unicode
It could be a problem in the data, e.g. with another program incorrectly submitting data.
I've seen all of these before now. You should use detailed logging (e.g. of the individual characters, in hex) to work out whether you've got the data correctly or not - that will tell you where to look next.
If you are using DataSource (f.e. com.mysql.jdbc.jdbc2.optional.MysqlDataSource) you can directly set channel encoding to UTF8 like ds.setEncoding("UTF-8")
I have an MS-Access database ( A English-telugu Dictionary database) which contains a table storing English words and telugu meanings.
I am writing a dictionary program in Java which queries the database for a keyword entered by the user and display the telugu meaning.
My Program is working fine till I get the data from the database, but when I displayed it on some component like JTextArea/JEditorPane/ etc... the telugu text is being displayed as '????'. Why is it happening?.
I have seen the solution for "1467412/reading-unicode-data-from-an-access-database-using-jdbc" which provides some workaround for Hebrew language. But it is not working for telugu. i.e I included setCharset("UTF8")before querying from the database. but still I am getting all '?'s.
As soon as I got data from Resultset I am checking the individual characters, all the telugu characters are being encoded by 63 only. This is my observation. I guess this must be some type of encoding problem. I would be very glad if somebody provides some solution for this. Thanks in advance.
After you get the text from the database, before you display in Java Swing widgets, are you setting the font? Set the font to "Gautami" and see whether it solves the problem;