A quest for Generated Keys in Kettle
Posted by Maarten Winkels in the early morning: August 28th, 2009
For my current project we use Kettle to process data from a number of sources and store it in a shared database. Kettle has great support for parsing data from a variety of sources, transforming it and writing it to a variety of destinations. One problem that often arises when inserting data in a relational database is the need for a syntactic, unique key that will be generated when a new row is inserted and later in the process used for other rows that refer the primary row. There are many solutions for this problem, both in the RDBMS and in the Java space. This blog reports on a search through several code bases to come up with a good solution in kettle which, unfortunately, still evades me.
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Why did Hibernate update my database?
Posted by Maarten Winkels in the early afternoon: April 6th, 2009
Hibernate is a sophisticated ORM framework, that will manage the state of your persistent data for you. Handing over the important but difficult task of managing persistent state of your application to a framework has numerous advantages, but one of the disadvantages is that you sort of lose control over what happens where and when. One example of this is the dirty checking feature that Hibernate provides. By doing dirty checking, Hibernate determines what data needs to be updated in your database. In many cases, this feature is quite useful and will work without any issues, but sometimes you might find that Hibernate decides to update something that you did not expect. Finding out why his happened can be a rather difficult task.
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Spicefactory – Part 1: Spice IT up, with Parsley, Cinnamon and Pimento
Posted by Maarten Winkels in the late evening: December 8th, 2008
In my article on InfoQ I've looked into how Grails and Flex can be combined to create a rapid application development platform. I think this is one of the most promising combinations for RIA development at the moment. The Flex space is very happening and there are many initiatives going on. A few days ago I encountered this one on the web: http://www.spicefactory.org/. Apart from the funny name, I think it is a very interesting initiative, because it brings some new concepts to the Flex remoting mix.
Configuring Hibernate and Spring for JTA
Posted by Maarten Winkels mid-afternoon: July 18th, 2008
Spring is a great framework for dependency injection and it comes with a lot of support classes and utilities for all kind of things. Hibernate is a persistence service with a lot of useful features, that is relatively easy to use. Configuring both frameworks is not always easy. Configuring them together is sometimes hard and it is easy to make mistakes.
This blog addresses a problem in a configuration that is fairly common: use Spring for transaction management on top of a JTA provider and use Hibernate for persistence. Transaction demarcation is easy and declarative with Spring. The problem is that Hibernate sometimes needs to detect the current transaction and this needs to be configured. This leads to hard to detect bugs in applications that rely on auto flushing.
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