Guillaume Piot | Application Developer & User Interface Designer » MySQL

Fixing a MySQL “incorrect string value” error when save unicode string

admin — Wed, 30 May 2012 16:49:10 +0000

I have recently been working with a CSV list of player names, which I needed to import into MySQL.

Using the CSV library in Python, I managed to read and slice my csv accordingly, here is an example:

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import csv
players = csv.reader(open('media/players.csv', 'rb'), delimiter=',', quotechar='|')
i = 0;
for row in players:
print row[1]
if i > 0:
player = Player.objects.get(id=i)
player.first_name = row[1]
player.save()
i = i+1

In the following example, I have already created the list of players, but some Polish characters in their name appear as “?”.

The problem is that the column in that database table (the one for the name) hasn’t got the right encoding charset, which should be UTF-8.

The best way to convert the column to UTF-8 is to run the following command in your mysql prompt, against the right database:

1	ALTER TABLE players_player MODIFY COLUMN first_name VARCHAR(255) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL;

Once you’ve done this, re-run your Python import/update script and the name should be saved with the right characters.

Watch slow queries on MySQL

admin — Tue, 30 Aug 2011 18:00:49 +0000

First login as root on the command line to MySQL:

mysql -u root -p mysql

Enter your mysql root password.

Set the log slow queries variables:

SET GLOBAL slow_query_log = 'ON';

Verify your variables are set properly:

SHOW VARIABLES;

You should have something like this:

slow_query_log       | ON

slow_query_log_file  | /var/lib/mysql/gp1-slow.log

Now you can check the log file to identify your slow heinous queries!

Reset root password for MySQL on Ubuntu

admin — Tue, 30 Aug 2011 17:50:52 +0000

Stop the MySQL Server.
```
sudo /etc/init.d/mysql stop
```
Start the mysqld configuration.
```
sudo mysqld --skip-grant-tables &
```
Login to MySQL as root.
```
mysql -u root mysql
```

Replace YOURNEWPASSWORD with your new password!

UPDATE user SET Password=PASSWORD('YOURNEWPASSWORD') WHERE User='root'; FLUSH PRIVILEGES; exit;

MySQL query cheat sheet

admin — Fri, 10 Sep 2010 11:24:00 +0000

Remove all rows from a table

TRUNCATE TABLE table_name;