Hi @Krzysztof Prokop ,

I'm assuming you are going with auto-generated columns on the grid to do this, right ?  As you don't know upfront the number and names of the warehouses ?

So, your data should have the shape :

     {"Name":"Cisco Catalyst 2960S-48LPS-L","warehouse1":0,"warehouse2": 0,"warehouse3:0,"warehouse4":8},
     {"Name":"Cisco Catalyst xxxxxxxxxxxxx","warehouse1":2,"warehouse2": 0,"warehouse3:0,"warehouse4":3,"warehouse5": 12}
]} 

If you don't know upfront what your warehouses will be, you can't create this as a structure to push into ArrangeData, so I'm not sure there is any way of doing this with ArrangeData action.  

I personally would make the JSON by hand, but OutSystems strongly emphasises that you should use ArrangeData and not bake your own cake.  It's up to you how you feel about that.

To be complete, your self made logic to replace the ArrangeData part, should result in something like (maybe you like to add an extra layer of entity name in there or not, up to you):

{
"data":[
     {"Name":"Cisco Catalyst 2960S-48LPS-L","warehouse1":0,"warehouse2":4,"warehouse3":8,"warehouse4":0},
     {"Name":"Cisco Catalyst xxxxxxxxxxxxx","warehouse1":2,"warehouse2":4,"warehouse4":0,"warehouse5":2}
],
"metadata":
     {"Name":"String","warehouse1":"Int32","warehouse2":"Int32","warehouse3":"Int32","warehouse4":"Int32","warehouse5":"Int32"}
}

Dorine