One of the major problems in developing a data integration application is writing transformation code. Many tools try to meet this need by providing a large number of operators that minimize coding through configuration.
Specialized operators are fine for basic transformations, but most ETL transformations require logic specific to the particular application. For that, tools resort to full featured coding tools such as Microsoft Visual Studio. expressor software has taken a different approach. The expressor Studio tool provides a light-weight scripting language called expressor Datascript and integrates an editing environment into each programmable operator. These tools allow development of transformation scripts of any level of complexity within the same interface.
As with any powerful programming language, expressor Datascript includes the ability to define and initialize variables, to control logic through if..then..else, while..do, repeat..until structures, to repeatedly run a block of code within a for loop, and to manipulate complex data formats. Extensive documentation for beginning to advanced programmers makes it easy to write specialized functions and to use the many functions built into expressor Datascript.
The expressor Studio interface simplifies script writing by putting functions and expression operators at the user’s fingertips in the Transform Editor.
Visual mapping aids creation of transformations, and the pre-structured assignment statement provides a starting point for the script. The expressor Studio also includes type-completion features to make it even easier to select and layout scripts.
Using expressor Datascript’s built-in functions, complex transformations can be written in the assignment statement. For example, this conditional statement uses the expressor Datascript decision function to perform multiple comparisons similar to an if..elseif..else code block.
Despite its complexity, this above statement was written entirely by selecting function names from drop down lists and simply entering the arguments to each of the nested functions.
The expressor Transform Editor also provides a pallet for writing customized functions and script structures that cannot be written, or the user does not want to write, in a single statement.
expressor’s scripting capabilities are quite powerful and available as part of their free expressor Studio application. I encourage you to check out expressor’s product if you haven’t done so already.
Reference: Pinal Dave (http://blog.SQLAuthority.com)