How to convert an entire MySQL database characterset and collation to UTF-8?

问题:

How can I convert entire MySQL database character-set to UTF-8 and collation to UTF-8?

回答1:

Use the ALTER DATABASE and ALTER TABLE commands.

ALTER DATABASE databasename CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci; ALTER TABLE tablename CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci; 

Or if you're still on MySQL 5.5.2 or older which didn't support 4-byte UTF-8, use utf8 instead of utf8mb4:

ALTER DATABASE databasename CHARACTER SET utf8 COLLATE utf8_unicode_ci; ALTER TABLE tablename CONVERT TO CHARACTER SET utf8 COLLATE utf8_unicode_ci; 

回答2:

1. Make a backup!

2. Then you need to set the default char sets on the database. This does not convert existing tables, it only sets the default for newly created tables.

   ALTER DATABASE dbname CHARACTER SET utf8 COLLATE utf8_general_ci; 

3. Then, you will need to convert the char set on all existing tables and their columns. This assumes that your current data is actually in the current char set. If your columns are set to one char set but your data is really stored in another then you will need to check the MySQL manual on how to handle this.

   ALTER TABLE tbl_name CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci; 

回答3:

On the commandline shell

If you're one the commandline shell, you can do this very quickly. Just fill in "dbname" :D

DB="dbname" (     echo 'ALTER DATABASE `'"$DB"'` CHARACTER SET utf8 COLLATE utf8_general_ci;'     mysql "$DB" -e "SHOW TABLES" --batch --skip-column-names \     | xargs -I{} echo 'ALTER TABLE `'{}'` CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;' ) \ | mysql "$DB" 

One-liner for simple copy/paste

DB="dbname"; ( echo 'ALTER DATABASE `'"$DB"'` CHARACTER SET utf8 COLLATE utf8_general_ci;'; mysql "$DB" -e "SHOW TABLES" --batch --skip-column-names | xargs -I{} echo 'ALTER TABLE `'{}'` CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;' ) | mysql "$DB" 

回答4:

You can create the sql to update all tables with:

SELECT CONCAT("ALTER TABLE ",TABLE_SCHEMA,".",TABLE_NAME," CHARACTER SET utf8 COLLATE utf8_general_ci;   ",     "ALTER TABLE ",TABLE_SCHEMA,".",TABLE_NAME," CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;  ")      AS alter_sql FROM information_schema.TABLES WHERE TABLE_SCHEMA = your_database_name; 

Capture the output and run it.

Arnold Daniels' answer above is more elegant.

回答5:

Before proceeding, ensure that you: Have completed a full database backup!

Step 1: Database Level Changes

• Identifying the Collation and Character set of your database

  SELECT DEFAULT_CHARACTER_SET_NAME, DEFAULT_COLLATION_NAME FROM  information_schema.SCHEMATA S WHERE schema_name = 'your_database_name' AND (DEFAULT_CHARACTER_SET_NAME != 'utf8'     OR  DEFAULT_COLLATION_NAME not like 'utf8%'); 

• Fixing the collation for the database

  ALTER DATABASE databasename CHARACTER SET utf8 COLLATE utf8_unicode_ci; 

Step 2: Table Level Changes

• Identifying Database Tables with the incorrect character set or collation

  SELECT CONCAT( 'ALTER TABLE ',  table_name, ' CHARACTER SET utf8 COLLATE utf8_general_ci;  ',  'ALTER TABLE ',  table_name, ' CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;  ') FROM information_schema.TABLES AS T, information_schema.`COLLATION_CHARACTER_SET_APPLICABILITY` AS C WHERE C.collation_name = T.table_collation AND T.table_schema = 'your_database_name' AND (C.CHARACTER_SET_NAME != 'utf8'     OR  C.COLLATION_NAME not like 'utf8%') 

• Adjusting table columns' collation and character set

Capture upper sql output and run it. (like following)

ALTER TABLE rma CHARACTER SET utf8 COLLATE utf8_general_ci;ALTER TABLE rma CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;   ALTER TABLE rma_history CHARACTER SET utf8 COLLATE utf8_general_ci;ALTER TABLE rma_history CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;   ALTER TABLE rma_products CHARACTER SET utf8 COLLATE utf8_general_ci;ALTER TABLE rma_products CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;   ALTER TABLE rma_report_period CHARACTER SET utf8 COLLATE utf8_general_ci;ALTER TABLE rma_report_period CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;   ALTER TABLE rma_reservation CHARACTER SET utf8 COLLATE utf8_general_ci;ALTER TABLE rma_reservation CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;   ALTER TABLE rma_supplier_return CHARACTER SET utf8 COLLATE utf8_general_ci;ALTER TABLE rma_supplier_return CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;   ALTER TABLE rma_supplier_return_history CHARACTER SET utf8 COLLATE utf8_general_ci;ALTER TABLE rma_supplier_return_history CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;   ALTER TABLE rma_supplier_return_product CHARACTER SET utf8 COLLATE utf8_general_ci;ALTER TABLE rma_supplier_return_product CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;  

refer to: https://confluence.atlassian.com/display/CONFKB/How+to+Fix+the+Collation+and+Character+Set+of+a+MySQL+Database

回答6:

Use HeidiSQL. Its free and a very good db tool.

From tools menu, enter Bulk table editor

Select the complete database or pick tables to convert,

• tick Change default collation: utf8mb4_general_ci
• tick Convert to charset: utf8

Execute

This converts complete database from latin to utf8 in just a few seconds.

Works like a charm :)

The real pitfall when moving from latin to utf8 is to make sure pdo connects with utf8 charset. If not you will get rubbish data inserted to the utf8 table and question marks all over the place on your web page, making you think the table data is not utf8...

回答7:

Inspired by @sdfor comment, here is a bash script that does the job

#!/bin/bash  printf "### Converting MySQL character set ###\n\n"  printf "Enter the encoding you want to set: " read -r CHARSET  # Get the MySQL username printf "Enter mysql username: " read -r USERNAME  # Get the MySQL password printf "Enter mysql password for user %s:" "$USERNAME" read -rs PASSWORD  DBLIST=( mydatabase1 mydatabase2 )  printf "\n"   for DB in "${DBLIST[@]}" do (     echo 'ALTER DATABASE `'"$DB"'` CHARACTER SET utf8 COLLATE `'"$CHARSET"'`;'     mysql "$DB" -u"$USERNAME" -p"$PASSWORD" -e "SHOW TABLES" --batch --skip-column-names \     | xargs -I{} echo 'ALTER TABLE `'{}'` CONVERT TO CHARACTER SET utf8 COLLATE `'"$CHARSET"'`;' ) \ | mysql "$DB" -u"$USERNAME" -p"$PASSWORD"  echo "$DB database done..." done  echo "### DONE ###" exit 

回答8:

For databases that have a high number of tables you can use a simple php script to update the charset of the database and all of the tables using the following:

$conn = mysqli_connect($host, $username, $password, $database);  if ($conn->connect_error) {   die("Connection failed: " . $conn->connect_error); }  $alter_database_charset_sql = "ALTER DATABASE ".$database." CHARACTER SET utf8 COLLATE utf8_unicode_ci"; mysqli_query($conn, $alter_database_charset_sql);  $show_tables_result = mysqli_query($conn, "SHOW TABLES"); $tables  = mysqli_fetch_all($show_tables_result);  foreach ($tables as $index => $table) {   $alter_table_sql = "ALTER TABLE ".$table[0]." CONVERT TO CHARACTER SET utf8  COLLATE utf8_unicode_ci";   $alter_table_result = mysqli_query($conn, $alter_table_sql);   echo "
";   var_dump($alter_table_result);   echo "
"; } 

回答9:

In case the data is not in the same character set you might consider this snippet from http://dev.mysql.com/doc/refman/5.0/en/charset-conversion.html

If the column has a nonbinary data type (CHAR, VARCHAR, TEXT), its contents should be encoded in the column character set, not some other character set. If the contents are encoded in a different character set, you can convert the column to use a binary data type first, and then to a nonbinary column with the desired character set.

Here is an example:

 ALTER TABLE t1 CHANGE c1 c1 BLOB;  ALTER TABLE t1 CHANGE c1 c1 VARCHAR(100) CHARACTER SET utf8; 

Aside:

I had a situation where certain characters "broke" in emails even though they were stored as UTF-8 in the database. If you are sending emails using utf8 data, you might want to also convert your emails to send in UTF8.

In PHPMailer, just update this line: public $CharSet = 'utf-8';

回答10:

mysqldump -uusername -ppassword -c -e --default-character-set=utf8 --single-transaction --skip-set-charset --add-drop-database -B dbname > dump.sql cp dump.sql dump-fixed.sql vim dump-fixed.sql   :%s/DEFAULT CHARACTER SET latin1/DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci/ :%s/DEFAULT CHARSET=latin1/DEFAULT CHARSET=utf8/ :wq  mysql -uusername -ppassword 

回答11:

If you cannot get your tables to convert or your table is always set to some non-utf8 character set, but you want utf8, your best bet might be to wipe it out and start over again and explicitly specify:

create database database_name character set utf8; 

回答12:

The only solution that worked for me: http://docs.moodle.org/23/en/Converting_your_MySQL_database_to_UTF8

Converting a database containing tables

mysqldump -uusername -ppassword -c -e --default-character-set=utf8 --single-transaction --skip-set-charset --add-drop-database -B dbname > dump.sql  cp dump.sql dump-fixed.sql vim dump-fixed.sql  :%s/DEFAULT CHARACTER SET latin1/DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci/ :%s/DEFAULT CHARSET=latin1/DEFAULT CHARSET=utf8/ :wq  mysql -uusername -ppassword 

回答13:

alter table table_name charset = 'utf8';

This is a simple query i was able to use for my case, you can change the table_name as per your requirement(s).

回答14:

To change the character set encoding to UTF-8 for the database itself, type the following command at the mysql> prompt. Replace DBNAME with the database name:

ALTER DATABASE DBNAME CHARACTER SET utf8 COLLATE utf8_general_ci; 

回答15:

You can also DB tool Navicat, which does it more easier.

• Siva.

Right Click Your Database & select DB Properties & Change as you desired in Drop Down

文章来源: How to convert an entire MySQL database characterset and collation to UTF-8?