Comments on: Fixing column encoding mess in MySQL

By: Jerk

Jerk — Sat, 23 Feb 2008 16:53:22 +0000

@Sven Neuhaus: That worked perfectly for Latin1 encoded chars in a UTF8 col. THANX!. That saved our lives.

By: SCC

SCC — Thu, 14 Feb 2008 06:17:15 +0000

I wish there was a way to change an entire table at once instead of going column by column. I need to convert from latin1_swedish_ci to UTF8 for dozens of columns.

By: shodan

shodan — Fri, 01 Feb 2008 00:03:49 +0000

Mohnkhan,
English is encoded exactly the same in both Latin-1 and UTF-8 so I’d simply go with everything in UTF-8 for unification.

By: Mohiuddin Khan Inamdar

Mohiuddin Khan Inamdar — Wed, 30 Jan 2008 02:07:58 +0000

I need some suggestion from you. I am working on web application which has partial English and partial Chinese simplified as text.
English is mainly used in the whole system. Chinese is used only to store additional information like address and Chinese specific name of employee. I had all my tables as default latin1 with collation as latin1_swedish_ci.. But as I had to add new field to the system to show Chinese info to employees who cannot handle English as their first language. I have changed all my fields to UTF-8, so that I can simply store anything anywhere Chinese.
however I have only about 10 columns in whole database which use Chinese. So is this the right thing I am doing ?
options i felt were right where in anybody can point me if I am wrong.
1.> keep everything as UTF-8, collation UTF9_general_ci
2.> keep all English columns as latin1 with collation as latin1_swedish_ci and chinese colums as as UTF-8, collation UTF9_general_ci
Database is stored on local server (intra net) not on internet So storage is not an issue
Any suggestions please.. they are welcome..
Thanks in advance..

Mohnkhan
http://www.mohitech.com

By: Blog Merge-- Valery’s Mlog

Blog Merge-- Valery’s Mlog — Wed, 16 Jan 2008 10:53:34 +0000

[...] си mysql_charsets.tar.gz съобразно една кратка и чудесна публикация в MySQL Performance Blog [...]

By: Sven Neuhaus

Sven Neuhaus — Fri, 04 Jan 2008 09:16:47 +0000

Thanks for the helpful article and comments.
So if the encoding is wrong (for example latin1 data in a column marked utf8) I would CHANGE COLUMN to binary (no conversion), then CHANGE COLUMN to latin1 (no conversion) and then CHANGE COLUMN to utf8 (conversion). I haven’t tried this yet but it sounds as if it’d work.

By: shodan

shodan — Tue, 18 Dec 2007 19:14:54 +0000

Right. I’ve just tested changing the column charset to binary and UTF-8 and can confirm it works fine. So the rule of thumb is:

1) if the encoding itself is OK for the whole table, but MySQL thinks there’s some other encoding, use CHANGE COLUMN to binary and back to proper encoding. (This is the case that jrabbit has.)

2) if the encoding itself is not OK, or if you only need to fix several rows, use CONVERT() tricks. (This is the case which I had.)

By: peter

peter — Tue, 18 Dec 2007 19:01:35 +0000

Teak,

I think you miss Andrews point a bit. It is not about the case when ALL data in the table is in wrong encoding but only single row (note id=123 in statements) Or may be several rows.

By: Teak

Teak — Tue, 18 Dec 2007 16:48:46 +0000

Altering the talbe type should be much quicker on big tables.

By: Scott

Scott — Tue, 18 Dec 2007 16:37:36 +0000

The manual shows doing the same thing, except altering the column type to binary and back. The CONVERT method is a little smoother, since it’s all one statement.

http://dev.mysql.com/doc/refman/5.0/en/charset-conversion.html