Actually isn't possibile delete multiple links of an existing wtpart structure using "import from spreadsheet" function.
The only way to delete existing links is to specify every single "child" number in the xls file with "DELETE" instruction, but in some situation users need to "recreate" quickly the bom in windchill without take care of actual latest iteration: we have provided an export of entire bom structure to xls file from a thirdy part software and the only way to be sure that bom structure inside windchill will be identical is:
- checking out parent wtpart
- deleting manually all nodes from existing structure
- checking in parent wtpart with empty structure
- execute an import from spreadsheet with "add and update" option
WTpart history won't be consistent, due to the fact that every time there's an iteration with empty bom to prepare a subsequent import.
We ask to provide a new option in windchill import from spreadsheet UI called "RECREATE BOM", with a warning message "this operation will remove all existing links from parent wtpart before import from sreadsheet, do you want to continue?"