The Hadoop Database (HBase) is well suited for creating a semantic Web and for extracting existing or computed knowledge. Learn how to represent RDF/XML assertions in an HBase database for scientific articles, and discover how HBase and Bigtable are promoting a new approach to storing and processing data.
Nowadays, with the widespread use and deployment of Object-Relational Mapping (ORM) tools, you don't generally have to think too hard about such arcane issues as composite keys. Normally, the choice of key design can be a simple integer, and this can be left with confidence to the tooling. Occasionally, you come across a situation where a composite key is required, and you need a strategy for this. This tip shows you how to implement composite keys with JPA and Hibernate.
This five-part series walks you through building a simple photo-sharing Web site using Perl and Apache to access Amazon's Simple Storage Service (S3) and SimpleDB. In this installment, follow your site's interaction with SimpleDB by learning how the URL creates a SimpleDB record for the uploaded file. Also learn how to create, edit, and delete comments as SimpleDB records on a photo for a particular user.
This article identifies enterprise data architecture dimensions that are used to analyze the requirements, constraints and boundaries in deciding an appropriate solution. This article explains in detail the various dimensions used in that reference that could yield richer insights when viewed using these perspectives.
Optional XML elements—for example, online forms—are special in that they might or might not appear in XML files. Representing such optional elements is a challenge both in programming languages and in databases. In many cases, null values are inserted in databases to represent empty optional elements, but null database XML values can be difficult to retrieve. Discover alternative, less-invasive approaches to handling optional XML elements without the need for data overloading or inserting null or other sentinel values.
While language-oriented toolsets become more advanced the range of development and deployment tools for databases remains primitive. How often is the DBA left sitting in the corner? Are you scared to change your database because other applications are using it? Do you have difficulty rolling out incremental changes to your databases? Does your database prevent you from releasing your software more frequently? Using real-world experiences - and the principles outlined in Ambler and Sadalage’s Refactoring Databases, this paper aims to demonstrate how to take control of the database and make it possible to incrementally evolve and improve its design. With these techniques the database need no longer be the bottleneck in your develop-test-deploy process. This paper features ideas on how to best use open source tools including Ant, CruiseControl and dbdeploy.
Here we examine data persistence patterns to help you determine which best suits your needs. We look at a number of patterns, including the Active Record, the Data Mapper, the Repository, the Identity Map, the Lazy Loading, and the Virtual Proxy.
This five-part series walks you through building a simple photo-sharing Web site using Perl and Apache to access Amazon's Simple Storage Service (S3) and SimpleDB. In this installment, get a feel for the benefits and drawbacks of S3 and SimpleDB by taking a tour of their architectures and starting to design your photo-sharing site.