To clear the query cache in your MySQL database manually, e.g. for database profiling, execute the following command in your...
Deadlocks only occur if two transactions in separate threads compete for the same rows in the database. They usually (but...
If you need to do calculations inside the database and can not use Ruby objects you may run into problems...
Occasionally some complex query must be processed on the database because building thousands of Ruby objects is impracticable.
CONCAT('foo', 'bar', NULL) = NULL the NULL always wins in MySQL. If you would rather treat NULL as...
Sometimes you inherit a non Rails or non Rack based web app such as PHP, Perl, Java / JEE, etc. I...
Use this MySQL command to show further info about a table: SHOW CREATE TABLE tags; This will output a table...
If a controller action responds to other formats than HTML (XML, PDF, Excel, JSON, ...), you can reach that code in...
If you want to see how long your database queries actually take, you need to disable MySQL's query cache...
It can be useful to have a Ruby expression like condition ? positive_case : negative_case in MySQL queries:
When you need to delete rows from a table, and the delete conditions require a joined table, MySQL needs to...
For some reason you want to define a find condition in array form. And in that condition both column name...
This will show you how to create a RSS feed that the Feed Validator considers valid. Note that RSS is...
The ECB has an XML feed with EURO exchange rates to other currencies. It is updated daily.
Update RubyGems and Passenger Bundler requires Rubygems >= 1.3.6. Run gem update --system if you have an older version.
When working with times and dates in Rails applications, you need to deal with the following problem: In Rails, Time...
In a nutshell: to avoid your shell character set from messing with imports, use -r to export and SOURCE when...
ALTER DATABASE database_name CHARACTER SET "utf8"; ALTER DATABASE database_name COLLATE "utf8_unicode_ci"; After that, for...
This may be awkward to set up, but will work once you're done. Fun facts:
Unless all MySQL server defaults are set to UTF-8, mysqldump encodes UTF-8 characters incorrectly and only outputs correct...
Most of these will not work in newer projects because these use the Capybara/Rack::Test combo in lieu of Webrat...
To parse XML-documents, I recommend the gem nokogiri. A few hints: xml = Nokogiri::XML(" foo bar ") parses an xml...
ObjectiveResource is an Objective-C port of Ruby on Rails' ActiveResource. It provides a way to serialize objects to and...
MMM (MySQL Master-Master Replication Manager) is a set of flexible scripts to perform monitoring/failover and management of MySQL Master...