Together with a set of rules regarding inheritance, it is easy to have one layer of the system configured for one character set whilst the actual data being introduced is using a different character set. Here is the core of the problem, the character encoding can be controlled from the application, database or even on a per table or column basis. Where do you set character sets in MySQL?
#Mysql character encoding list code#
Each character can be associated by several different codes, and one code may correspond to several different characters, depending on the encoding scheme used. Popular schemes include ASCII and Unicode, and can include language specific character sets such as Latin US, Latin1, Latin2 which are commonly used in America and Europe and EUC-KR or GB18030 which support language characters with an Asian origin. The encoding is the binary representation of glyphs, where each character can be represented by 1 or more bytes.
#Mysql character encoding list how to#
Since slides don't tell the whole story, we decided to create a series of blog posts to demonstrate how easy it is to go wrong, how to fix some of the issues and how to avoid such issues in the future. The slides from the presentation are available on slideshare. In short, there are a myriad of places where character encoding can be controlled, which gives ample opportunity for the system to break and for text to become unrecoverable. Modify the default character set of the table first alter table xxx character set utf8mb4 Īt this time, you only need to change the column again, and only specify non empty character sets, show create table xxx When viewing, you will find that the column has no specified character set, so it will use the default character set of the table.Recently at FOSDEM, Maciej presented "Breaking and unbreaking your data", a presentation about the potential problems you can incur regarding character encoding whilst working with MySQL. When I use change and add the non empty and character set settings, I will report a syntax error. As a result, when I use the change statement above to modify, the non empty attribute of the original column will disappear. When modifying the column character set at one time, the default character set of the table is Latin1. Modify coding format Modify database character set:ĪLTER DATABASE db_name DEFAULT CHARACTER SET character_name Change the default character set and all character columns (char, varchar, text) of the table to a new character set:ĪLTER TABLE tbl_name CONVERT TO CHARACTER SET character_name įor example: alter table logtest convert to character set utf8 collate utf8_ general_ ci Only modify the default character set of the table:ĪLTER TABLE tbl_name DEFAULT CHARACTER SET character_name įor example: alter table logtest default character set utf8 collate utf8_ general_ ci Modify the character set of the field:ĪLTER TABLE tbl_name CHANGE c_name c_name CHARACTER SET character_name įor example: alter table logtest change Title varchar (100) character set utf8 collate utf8_ general_ ci Note: When writing back-end services to insert data into mysql, errors are always reported due to character coding.
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