So, I currently have this problem - I have a sql db dump and the character encoding in it is latin1, but there are some utf8 chars in the file that look like Ä (should be ā) Ä« (should be ī) Å¡ (should be š) Ä“ (should be ē) etc. How do I convert these leters back to the original utf8.?
Character in the file <-> what it should have been <-> bytes
Ä“ <-> ē <-> 5
Ä <-> ā <-> 2
Å¡ <-> š <-> 4
Ä« <-> ī <-> 4
If you're seeing multiple bytes for what should be single characters, chances are it's already in UTF-8. Bear in mind that ISO-8859-1 is a single-byte-per-character encoding, whereas UTF-8 can take multiple bytes - and any non-ASCII character does take multiple bytes.
I suggest you open the file in a UTF-8-aware text editor, and check it there.
Encoding should be set on the connection on which you import data and read out data. If both of them are set to UTF-8, you will face no problems.
If you however import them with a latin1 connection, and later on reading it out with a UTF-8, you're in a world of trouble.
PHP internally only handles latin1, however that isn't nessecarily a problem for you.
If you have already wrongly imported the data, you would see a lot of ? or (diamond + ?) on your output I think.
But basically, when connecting frmo PHP, make sure to invoke SET NAMES 'utf8' first thing you do and see if that works.
If data still is wrong, you could use PHPs functions utf8_encode / utf8_decode to convert the data that is problematic.
In a working scenario they should never be used though.
Related
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 (There is a newer version of the Unicode collation in the pipeline.)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 am trying to understand the difference between Latin1 and UTF8 and for the most part I get it, however, when testing I am getting some weird results and could use some help clarifying
I am testing with 'é' (Latin small letter E with acute) and the link below shows the hex c3a9
I setup a database and specified utf8 as the character set, then created a table with utf8 as the character set and inserted a record with the character 'é' after setting the connection and client character set to UTF8
when I do a select hex(field), field from test_table I get:
hex(field), field
C3A9, é
This is fine and consistent with what I read, however, when I do the exact same using a latin1 character set I get the following:
hex(field), field
C3A9, é
but if I enter char(x'E9') which should be the single byte Latin1 equivalent value for é I manage to get it to display correctly using 'set names UTF8' but it doesn't show up correctly when setting the connection and client to Latin1
Can anyone clarify? - shouldn't Latin1 characters be single byte (Hex E9) in both UTF8 and Latin1? or am I completely misunderstanding it all?
Thanks
latin1 encoding has only 1-byte codes.
The first 128 codes (7-bits) are mostly identical between latin1 and utf8.
é is beyond the 128; it's 1-byte, 8-bit latin1 hex is E9 (as you observed). For utf8, it takes 2 bytes: C3A9. For most Asian characters, utf8 takes 3 byte; latin1 cannot represent those characters.
MySQL has the confusing command SET NAMES utf8. That announces that the client's encoding is utf8, and instructs the communication between client and server to convert between the column's CHARACTER SET and utf8 when reading/writing.
If you have SET NAMES latin1 (the old default), but the bytes in the client are encoded utf8, then you are 'lying', and various nasty things happen. But there is no immediate clue that something is wrong.
Checklist for going entirely utf8:
Bytes in client are utf8-encoded
SET NAMES utf8 (or equivalent parameter during connecting to MySQL)
CHARACTER SET utf8 on column or table declaration
<meta ... UTF-8> in html
After recently putting a website through the ringer UTF-8 wise I think this is a case of viewing UTF-8 data in a latin1 table within a UTF-8 encoded page or terminal.
If you are using a terminal you can check this by looking at the character encoding setting of the terminal (in Ubuntu it's Terminal -> Set Character Encoding). If you are using something like PHPMyAdmin, view the page source and look for the charset of the page, or open up Firebug and look at the response headers for the page, it should say "UTF-8".
If you've inserted the data and it's encoded in UTF-8 and it goes into a latin1 table then the data will still be stored in UTF-8, it's only when you start viewing that data or retrieving that data in a different encoding that you start getting the mangled effect.
I've found it's really crucial that when you are working with character encoding that you get everything the same: the page must have a charset of UTF-8, the upstream into the database must be in UTF-8, the database must have a default charset and storage of UTF-8. As soon as you put a different charset in the mix everything goes crazy.
We are trying to migrate database content (with a PHP script).
Content has been copied into a CMS and then written to the database. Content copied could be from any character encoding scheme (e.g. IS0-...-14) and any website.
The PHP CMS is UTF-8 so the character pasted into a textbox would be converted to UTF-8 when it was POSTed but then written to the database as Latin-1 (MSSQL db...db charset and query charset both latin-1).
We are desperately trying to think up how this could be reversed or if it is even possible (to get it so the character is fully UTF-8) in PHP.
If we can get the logic we can write an extension in C++ if PHP cant handle it (which it probably cant, mb_shite and iconv).
I keep getting lost in UTF-8 4 byte character streams (i.e. 0-127 is..ect).
Anybody got any ideas?
So far we have used PHP's ord() function to try and produce a Unicode/Acsii char ref for each char (I know ord returns ASCII but it prints character numbers over 128 which I thought was wierd if it is just meant to be ASCII, or maybe it repeats itself).
My thoughts are the latin1 will struggle to convert back to UTF-8 and will result in black diamond due to single byte char stream in Latin1 (ISO-...-1).
If latin1 is an 8-bit clean encoding for your database (it is in MySQL, donno about MSSQL), then you don't need to do anything to reconstruct the utf-8 string. When you pull it out of your database into PHP you will get back the same bytes you put in, i.e. UTF-8.
If latin1 is not an 8-bit-clean encoding for your database then your strings are irretrievably broken. This means any characters which the database considered invalid were either dropped or replaced the moment you wrote your utf-8 string to the database. There isn't any way to recover from this.
I have a MySQL table & fields that are all set to UTF-8. The thing is, a previous PHP script, which was in charge of the database writing, was using some other encoding, not sure whether it is in the script itself, the MySQL connection or somewhere else. The result is that although the table & fields are set to UTF-8, we see the wrong chars instead of Chinese.
It looks like that:
Now, the previous scripts (which were in charge of the writing and corrupted the data) can read it well for some reason, but my new script which all encoded in UTF-8, shows chars like ½©. How can that be fixed?
By the sound of it, you have a utf8 column but you are writing to it and reading from it using a latin1 connection, so what is actually being stored in the table is mis-encoded. Your problem is that when you read from the table using a utf8 connection, you see the data that's actually stored there, which is why it looks wrong. You can fix the mis-encoded data in the table by converting to latin1, then back to utf8 via the binary character set (three steps in total).
The original database was in a Chinese encoding – GB-18030 or similar, not Latin-1 – and the bytes that make up these characters, when displayed in UTF-8, show up as a bunch of Latin diacritics. Read each string as GB-18030, convert it to UTF-8, and save.
I'm migrating a db from mysql to postgresql. The mysql db's default collation is UTF8, postgres is also using UTF8, and I'm encoding the data with pg_escape_string(). For whatever reason however, I'm running into some funky errors about bad encoding:
pg_query() [function.pg-query]: Query failed: ERROR: invalid byte sequence for encoding "UTF8": 0xeb7374
HINT: This error can also happen if the byte sequence does not match the encoding expected by the server, which is controlled by "client"
I've been poking around trying to figure this out, and noticed that php is doing something weird; if a string has only ascii chars in it (eg. "hello"), the encoding is ASCII. If the string contains any non ascii chars, it says the encoding is UTF8 (eg. "Hëllo").
When I use utf8_encode() on strings that are already UTF8, it kills the special chars and makes them all messed up, so.. what can I do to get this to work?
(the exact char hanging it up right now is "�", but instead of just search/replace, i'd like to find a better solution so this kinda problem doesn't happen again)
Most likely, the data in your MySQL database isn't UTF8. It's a pretty common scenario. MySQL at least used to not do any proper validation at all on the data, so it accepted anything you threw at it as UTF8 as long as your client claimed it was UTF8. They may have fixed that by now (or not, I don't know if they even consider it a problem), but you may already have incorrectly encoded data in the db. PostgreSQL, of course, performs full validation when you load it, and thus it may fail.
You may want to feed the data through something like iconv that can be set to ignore unknown characters, or transform them to "best guess".
BTW, an ASCII string is exactly the same in UTF-8 because they share the same first 127 characters; so "Hello" in ASCII is exactly the same as "Hello" in UTF-8, there's no conversion needed.
The collation in the table may be UTF-8 but you may not be fetching information from it in the same encoding. Now if you have trouble with information you give to pg_escape_string it's probably because you're assuming content fetched from MySQL is encoded in UTF-8 while it's not. I suggest you look at this page on MySQL documentation and see the encoding of your connection; you're probably fetching from a table where the collation is UTF-8 but you're connection is something like Latin-1 (where special characters such as çéèêöà etc won't be encoded in UTF-8).