XML Stage: Establish Meaningful Link Names

…and then stick with them! Decide early what you want your Link names to be, before you even open up the Stage and begin your work on the Assembly, and then lock them in. Make a conscious decision not to change or alter them. Why? The XML Stage is not immune to Link name changes like other Stages and Connectors on the DataStage canvas.

How many of you are perfectly happy with DSLink2 and DSLink35 or other automatically generated Link names? I know I don’t spend time on every Job, running around putting on fancy Link names, especially when I’m first building it. It’s nice for documentation, and I know that I should always create meaningful names, but how many of us do?

And how often do we “go back” and edit the Link names later? That’s actually a good thing — for most Stages and Connectors. But for the XML Stage, it is something you want to avoid. Changing Link names will break your Assembly and require that you edit the stage and make changes.

Here is an example of the XML Stage reading xml documents from a subdirectory and performing validation. Valid xml will be sent down the “goodXML” Link, and rejected, invalid xml content will be send down the “badXML” link.

linknames

Notice how, inside the Assembly, these link names are used. Here in the Assembly Parser step, you see the toXML linkname used for the specification of the xml Source:

linknameParserStep

…and here, in the Assembly Output Step, you can see how the Link names are used in the Mapping:

linknamesOutputStep

Those screen shots illustrate how the link name becomes critical to the internals of the Assembly. If you change the link names outside the Stage, the Assembly will end up with errors (various red marks throughout the Assembly, depending on how complex it is):

redLink

Are you able to correct the Assembly when this happens? Of course…and for most scenarios, it’s not difficult…you might just need to change a setting or re-map a couple of columns. But save yourself the trouble. Decide on your Link names, set them up early (preferably before you ever enter the Stage) and then don’t touch them!

—Ernie

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