Unable to add a list to a link between two datatypes

I have a datatype called Tool. Instead of overloading it with a lot of info, I created another datatype called ToolData.

Everytime a new Tool is created, a ToolData is also created and both reference to each other.
Tool has a field called LinkToToolData
ToolData has a field called LinkToTool.

When this goes through, the ToolData gets the LinkToTool
But Tool doesn’t get the LinkTotoolData. The fiels still stays empty.

What is the mistake here ?

Also, a major question I have is, is it even necessary to have two datatypes to store all the information about Tools, like upvoter list etc.

Hi there, @vamshipampari… what you are showing in your screenshots looks like it should work. Have you tried running the workflow in step-by-step mode to see if the debugger can help you understand why it’s not working?

Depending on how many fields the ToolData data type has (I’m guessing we’re not talking about a lot of fields here), it’s probably not necessary to have two data types (that being said, it doesn’t necessarily hurt to have two, either). Since you mentioned a list field, one thing to consider is how big any lists might get. If a list could have significantly more than 100 items in it, you should probably consider having a separate data type to store a thing for each association in the list.

Hope this helps.