How to make MySQL handle UTF-8 properly

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被撕碎了的回忆 2020-11-22 06:38

One of the responses to a question I asked yesterday suggested that I should make sure my database can handle UTF-8 characters correctly. How I can do this with MySQL?

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  • 2020-11-22 07:05

    DATABASE CONNECTION TO UTF-8

    $connect = mysql_connect('$localhost','$username','$password') or die(mysql_error());
    mysql_set_charset('utf8',$connect);
    mysql_select_db('$database_name','$connect') or die(mysql_error());
    
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  • 2020-11-22 07:06

    The charset is a property of the database (default) and the table. You can have a look (MySQL commands):

    show create database foo; 
    > CREATE DATABASE  `foo`.`foo` /*!40100 DEFAULT CHARACTER SET latin1 */
    
    show create table foo.bar;
    > lots of stuff ending with
    > ) ENGINE=InnoDB AUTO_INCREMENT=252 DEFAULT CHARSET=latin1
    

    In other words; it's quite easy to check your database charset or change it:

    ALTER TABLE `foo`.`bar` CHARACTER SET utf8;
    
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  • 2020-11-22 07:06

    Your answer is you can configure by MySql Settings. In My Answer may be something gone out of context but this is also know is help for you.
    how to configure Character Set and Collation.

    For applications that store data using the default MySQL character set and collation (latin1, latin1_swedish_ci), no special configuration should be needed. If applications require data storage using a different character set or collation, you can configure character set information several ways:

    • Specify character settings per database. For example, applications that use one database might require utf8, whereas applications that use another database might require sjis.
    • Specify character settings at server startup. This causes the server to use the given settings for all applications that do not make other arrangements.
    • Specify character settings at configuration time, if you build MySQL from source. This causes the server to use the given settings for all applications, without having to specify them at server startup.

    The examples shown here for your question to set utf8 character set , here also set collation for more helpful(utf8_general_ci collation`).

    Specify character settings per database

      CREATE DATABASE new_db
      DEFAULT CHARACTER SET utf8
      DEFAULT COLLATE utf8_general_ci;
    

    Specify character settings at server startup

    [mysqld]
    character-set-server=utf8
    collation-server=utf8_general_ci
    

    Specify character settings at MySQL configuration time

    shell> cmake . -DDEFAULT_CHARSET=utf8 \
               -DDEFAULT_COLLATION=utf8_general_ci
    

    To see the values of the character set and collation system variables that apply to your connection, use these statements:

    SHOW VARIABLES LIKE 'character_set%';
    SHOW VARIABLES LIKE 'collation%';
    

    This May be lengthy answer but there is all way, you can use. Hopeful my answer is helpful for you. for more information http://dev.mysql.com/doc/refman/5.7/en/charset-applications.html

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  • 2020-11-22 07:07

    Update:

    Short answer - You should almost always be using the utf8mb4 charset and utf8mb4_unicode_ci collation.

    To alter database:

    ALTER DATABASE dbname CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
    

    See:

    • Aaron's comment on this answer How to make MySQL handle UTF-8 properly

    • What's the difference between utf8_general_ci and utf8_unicode_ci

    • Conversion guide: https://dev.mysql.com/doc/refman/5.5/en/charset-unicode-conversion.html

    Original Answer:

    MySQL 4.1 and above has a default character set of UTF-8. You can verify this in your my.cnf file, remember to set both client and server (default-character-set and character-set-server).

    If you have existing data that you wish to convert to UTF-8, dump your database, and import it back as UTF-8 making sure:

    • use SET NAMES utf8 before you query/insert into the database
    • use DEFAULT CHARSET=utf8 when creating new tables
    • at this point your MySQL client and server should be in UTF-8 (see my.cnf). remember any languages you use (such as PHP) must be UTF-8 as well. Some versions of PHP will use their own MySQL client library, which may not be UTF-8 aware.

    If you do want to migrate existing data remember to backup first! Lots of weird choping of data can happen when things don't go as planned!

    Some resources:

    • complete UTF-8 migration (cdbaby.com)
    • article on UTF-8 readiness of php functions (note some of this information is outdated)
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  • 2020-11-22 07:10

    The short answer: Use utf8mb4 in 4 places:

    • The bytes in your client are utf8, not latin1/cp1251/etc.
    • SET NAMES utf8mb4 or something equivalent when establishing the client's connection to MySQL
    • CHARACTER SET utf8mb4 on all tables/columns -- except columns that are strictly ascii/hex/country_code/zip_code/etc.
    • <meta charset charset=UTF-8> if you are outputting to HTML. (Yes the spelling is different here.)

    More info ;
    UTF8 all the way

    The above links provide the "detailed canonical answer is required to address all the concerns". -- There is a space limit on this forum.

    Edit

    In addition to CHARACTER SET utf8mb4 containing "all" the world's characters, COLLATION utf8mb4_unicode_520_ci is arguable the 'best all-around' collation to use. (There are also Turkish, Spanish, etc, collations for those who want the nuances in those languages.)

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  • 2020-11-22 07:11

    Set your database collation to UTF-8 then apply table collation to database default.

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