Wrapped Metanodes, Metanodes and Flow Variables

I am trying to create a template Wrapped Metanode for a number of nodes, with flow variables. I ass-u-me Wrapped Metanodes are best for new development. My main problem is being able to find the best documentation for how to configure the Flow Variables.

Where is the best documentation that discusses in detail how to configure flow variables with a Wrapped Metanode Template?

BTW, I’m trying to develop the Wrapped Metanode template, so that I can configure Workflow Variables external to the (Wrapped) Metanode. I have a complex set of nodes that reads from an API (JSON), and saves to SQL Server. I want to be able to use lots of the Wrapped Metanodes (from the template), which each having a different API URL and target SQL Server table name.

I ass-u-me, I’ll run into problems if I have the quick-form (API URL, target SQL Server, etc., Flow Variables) defined in the Wrapped Metanode, unless I unlink, but that sort-of kills the advantages of using a template, should I make a minor change to the template in the future.

OK, I stumbled-through; I ended-up using a Metanode (not Wrapped), and a Metanode template.

Now, though, how do I make sure that everything in a Metanode is executed BEFORE control passes to the next node after the meta-node? I have a database connection passed-through the Metanode from input to output, and I find that a node after the Metanode which uses the database connection runs before the Metanode completes execution.

Hello Bassman,

you can use the flow variable connection to specify control dependencies i.e. in which order two nodes have to run. Let’s say you have a slower node that maybe does some model training and a fast node like a database node which really only does some configurations. You can draw a flow variable connection from the slow node to the fast node to make sure that the fast node is executed only after the slow node finished its execution.



Yes, I just did that, in conjuction with converting a rather complex Metanode that I need to finish to completion, before moving on to the next node, to Wrapped, and making a Flow Variable connection between the Wrapped Metanode and the next node.

I had been trying previously to use only Wrapped Metanodes for everything (newer is better?), but for now, I am using a combination of Wrapped Metanodes and legacy Metanodes.

I need to get better with KNIME basics before I truly understand what I am doing. I”ll probably get a couple of the KNIME books at some point. I”m getting past what the videos and Node Pit can help me understand.

My use-case is only JSON ETL loading at this time in conjunction with SQL Server and Power BI Desktop. I hope to get into some more interesting KNIME analysis at some point, but doubt I will ever use BIRT or R.

Hello Bassman,

since you are dealing a lot with meta nodes I guess you might find our latest blog post (https://www.knime.com/blog/wrapped-metanodes-and-metanode-templates-in-knime-analytics-platform) informative :wink: