Hibernate. Rquery - nickelcode. The 26th is the first day of instruction in the first academic year of my PhD in Computer Science at UCLA. I have a two year old daughter, an incredibly supportive wife, and I just turned 30. Unsurprisingly, I've been asked many times why I want to get a PhD and I rarely get a chance to explain my thinking fully. This post is both a detailed account of my reasons and a counterpoint to the popular opinion that there isn't much value in higher education in Computer Science.
Why Bother? Any confusion or surprise over my decision to go back to school can generally be reduced to a simple idea: the success I would otherwise have while getting my PhD is of greater absolute value than the education. This comes in many reasonable forms. Why are you leaving such a high paying job? In some cases there is a subtle suggestion that academia and higher education are losing their value. Career Path The thing that got to me was the amount of time I spent staring at my email client. What Interests Me. O/R-Ms: Panacea or Polio Braces? In case you haven’t heard, there is a huge difference between the way that software developers and database professionals operate – there are accepted use paradigms and development methodologies for both worlds.
Unfortunately for everyone, they don’t match up. Object-oriented programming languages operate on single entities: objects. Databases work with sets. Objects sometimes have relationships that are difficult to effectively map in a relational database. Database entities frequently do not even correspond to application entities. Object-Relational Mappers, O/R-Ms, are often hailed as the solution to the differences between object-oriented code and the relational storage layer.
Magical Snake Oil A lot of developers see the database as nothing more than a hole for objects. Not quite, it appears. Isn’t one of the reasons for using O/R-Ms to cut down on the amount of difficult, “specialized” code that you have to write? Shackled to the Solution But my database is just an object store. Are ORMs really a thing of the past ? Stephan Schmidt has blogged on the ORMs being a thing of the past.
While he emphasizes on ORMs' performance concerns and dismisses them as leaky abstractions that throw LazyInitializationException, he does not present any concrete alternative. In his concluding section on alternatives he mentions .. "What about less boiler plate code due to ORMs? Good DAOs with standard CRUD implementations help there. Unfortunately, all these things work on small projects with a few number of tables. It's very true that none of the ORMs in the market today are without their pains. Yet, in the Java stack, Hibernate and JPA are still the best of options when we talk about big persistent domain models.
If you are not designing an ActiveRecord based model, it's of paramount importance that you keep your domain model decoupled from the persistent model. Announcing Frog.NET. The Vietnam of Computer Science. (Two years ago, at Microsoft's TechEd in San Diego, I was involved in a conversation at an after-conference event with Harry Pierson and Clemens Vasters, and as is typical when the three of us get together, architectural topics were at the forefront of our discussions. An crowd gathered around us, and it turned into an impromptu birds-of-a-feather session. The subject of object/relational mapping technologies came up, and it was there and then that I first coined the phrase, "Object/relational mapping is the Vietnam of Computer Science". In the intervening time, I've received numerous requests to flesh out the discussion behind that statement, and given Microsoft's recent announcement regarding "entity support" in ADO.NET 3.0 and the acceptance of the Java Persistence API as a replacement for both EJB Entity Beans and JDO, it seemed time to do exactly that.)
No armed conflict in US history haunts the American military more than $g(Vietnam). History Johnson's War Nixon's Promise War's End. ORMs vs. Query Builders: Database portability. There has been some discussion in recent days regarding Object-Relational Mappers (ORMs), Drupal, and why the latter doesn't use the former. There are, actually, many reasons for that, and for why Drupal doesn't do more with the Active Record pattern.
Rather than tuck such discussion away in an issue queue, I figured it better to document a bit more widely. On ORMs in Drupal I highly recommend that people read The Vietnam of Computer Science. It does an extremely good job of laying out why OO<->SQL mapping is a fundamentally intractable problem. Because of its stateless nature, PHP doesn't lend itself well to the latter method. In contrast, it is difficult to find a web host that doesn't offer MySQL. So for now and for the foreseeable future, favoring relational data over object data for PHP, and Drupal in particular, seems the better strategy than gutting and rewriting Drupal entirely for CouchDB, Bigtable, Oracle-specific object stores, or whatever else. The DBTNG approach. To ORM or Not to ORM. Five Reasons for using an O/R Mapping (ORM) Code Generation Tool.
Author: Iqbal M. Khan So, why should you use any O/R mapping (ORM) tool? I am not talking about a specific tool but rather all ORM tools in general. There are a number of reasons for using an ORM tool but before I dive into that, let me give you a brief overview of what an O/R mapping tool really is. An O/R mapping tool generates persistence objects for your .NET application. It is a modeling and code generation tool that connects to your database and reads its schema, then lets you map objects to database tables and views, specify single-row insert, update, load, and delete operations, queries and stored procedure calls, as methods to these objects.
And, it also lets you define one-to-one, one-to-many, many-to-one, and many-to-many relationships between objects based on relationships between tables in the database. There are many other features that a good ORM (Object relational Mapper) provides but I'm keeping my description brief so I can talk more about the benefits. Author: Iqbal M. Activeobjects: Home. Database heresies. While scanning reddit, I saw an article pop up by Jeff Davis lamenting the way most people interact with databases, particularly when it comes to ORMs. Jeff seems to be pointing out (and, to an extent, conflating) two issues: At the moment, programming languages and SQL don’t really mesh all that well. Most people, in Jeff’s opinion, take the wrong approach to working with a database from their programming language of choice. The first point is one I’m happy to concede; SQL is a fundamentally different beast from, well, pretty much any other language you’re likely to encounter, and as such common/popular programming languages run into a big impedance mismatch the moment they start trying to do SQL.
So I’m in agreement on that point. Two ways to do it Jeff lays out two approaches to database interaction. Meanwhile, there’s the “right way”: This dichotomy is somewhat similar to what I’ve been saying, for a couple years now, to anyone who’s willing to listen to me ramble about ORM design. ORM, schmorm.