n8n-docs/docs/data/data-mapping/data-item-linking/item-linking-errors.md
2024-01-09 10:36:56 +00:00

50 lines
1.4 KiB
Markdown

---
contentType: reference
---
# Item linking errors
n8n displays errors related to data mapping when there are problems tracing an item's linked parent items back through the workflow.
## Errors when pinning data
If you see this error message:
<!-- vale off -->
> ERROR: '`<node-name>`' must be unpinned to execute
<!-- vale on -->
Unpin the data in the named node, and execute the node to get fresh data.
This error has two possible causes:
* The number of inputs into the pinned node has changed since you pinned it.
* You've edited the pinned data and changed the number of items.
## Errors when using the Code node
If you see this error message:
> ERROR: Can't get data for expression under '`<field-name>`' field
You need to supply item linking information yourself, because you have an item linking scenario that n8n can't automatically handle.
To control item linking, set `pairedItem` when returning data. For example, to link to the item at index 0:
```js
[
{
"json": {
. . .
},
// The index of the input item that generated this output item
"pairedItem": 0
}
]
```
Refer to [Item linking concepts](/data/data-mapping/data-item-linking/item-linking-concepts/) for a conceptual understanding of item linking, and [Manage item linking in the Code node](/data/data-mapping/data-item-linking/item-linking-code-node/) for detailed guidance on handling item linking.