Relational databases define a strict structure and provide a rigid way to maintain data for a software application. Apache's open source CouchDB offers a new method of storing data, in what is referred to as a schema-free document-oriented database model. Instead of the highly structured data storage of a relational model, CouchDB stores data in a semi-structured fashion, using a JavaScript-based view model for generating structured aggregation and report results from these semi-structured documents. CouchDB has been developed from the ground up with Web applications as the primary focus and has its sights on becoming the de-facto database for Web application development.

Amazon's Relational Database Service (RDS) offloads the work of maintaining a database to Amazon Web Services, which makes it exceptionally easy to increase or swap out your application's data storage. This month, Andrew Glover revisits his location-based cloud-to-mobile application, swapping the original NoSQL datastore for a traditional RDBMS. It's a breeze using the Play framework and the AWS console.

There are a number of challenges that make the deployment task more difficult. Alex reviews the common techniques for deploying new databases and upgrading existing ones, and their flaws, and argues the advantages of an automated, incremental, script-based approach to deployments

Database testing is one of the areas that might have the smaller number of open source tools. The programming languages have many xUnit tools and mocking frameworks, but this is not the case for databases. This article provides a list of open source tools that can be used to perform unit, load and security testing on several relational and NoSQL databases.

Describes techiques (such as an in-memory database) for reducing the execution time and maintenance costs of automated regression test suites.

One pattern that shows up repeatedly is creating a Many-to-Many relationship using a mapping class. In Rails, the hasMany/through directive provides this functionality. Grails doesn't have an explicit hasMany/through statement like Rails. Rather, Many-to-Many relationships are created implicitly by GORM via your domain classes.

Although many developers use object-relational mapping (ORM) tools for their applications' persistence tier, some are confused about how to use them and duplicate code unnecessarily. The authors' experience constructing many persistence tiers has given them a clear understanding of persistence patterns and best practices. The first part of this two-part article covers the basics of a consistent, concise domain model and persistence tier. Part 2 builds and expands on the concepts covered in this article.

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.

This article discusses the benefits that are available when you replicate parts of production databases for software development and software testing.

Agile methodologies work well with database developments only if great care is taken to do things right. It requires good judgement and leaves little room for error. Dev Nambi, in an extract from the book Tribal SQL, argues that Agile works for smart, curious, and experienced software engineers.