A very traditional niche of scripting languages, (such as Perl, Python or Ruby), has been in the ad hoc manipulation of databases – from grabbing data, transforming it, performing bulk updates, right on through to full-on data migration projects that move data from one platform or RDBMS to another. Scripting languages are perfect for these types of task because they are quick to write and test, can be used interactively while the problem space is being explored, and because extraneous features – such as graphical user interface, detailed user documentation and so on – are not required.
For hardcore Java hackers, much of this kind of ad hoc activity has either entailed writing utilities libraries or, more likely, dropping down into another language – from Unix shell scripts to the aforementioned Perl, Python, Ruby et al. Now, however, Groovy exists to provide all of the benefits of a dynamically-typed scripting language that is designed to be easily accessible to Java developers and which sits on top of the Java Virtual Machine (JVM) and, as a big bonus, can make use of existing Java APIs and packages.
In the case of database access, Groovy can be used both with the standard Java JDBC mechanism (which makes use of SQL) or with its own high-level SQL-less DataSet libraries. In this two-part hands-on tutorial we'll look at how you can use Groovy to quickly and easily interface with a MySQL database sitting on a remote server somewhere.
First things first, though, and that's to install Groovy and to check that it all runs smoothly. Groovy can be downloaded here - there are install packages for various platforms, including Windows, Linux, and a platform-independent zip.
Aside from dropping the files into the right place the only other things to do are set the GROOVY_HOME environment variable (and JAVA_HOME if it doesn't already exist), and to make sure that the \groovy\bin directory is on your path.
A quick way to test is simply to open a command shell or terminal and type:
This should come back with the versions of Groovy and Java that you have installed.
The only other thing you need to have in place is a JDBC driver for MySQL. The jar file needs to be on the classpath; simply copying the file to the \groovy\lib is enough to banish any problems.
For the purposes of this article we'll be looking at a simple database (called pers) which contains a single table, called users, which is represented by the following grid: