This article explains how AODocs resolves and updates lookup properties – the read-only values a document pulls from another document it links to. Learn more: What are lookup properties?
Automatically generated table of contents
When you save a document (the values are pulled in)
Whenever a document is created, saved, or imported – including drafts – AODocs resolves its lookup properties:
- It reads which document the link field points to.
- It loads that linked document.
- It copies the value of each linked property into the matching lookup property, and shows the linked document's title on the link field.
If the link field is empty, the lookup properties are simply left empty.
Note: Lookup properties are resolved before calculated fields, so a formula can safely use a value that was pulled in by a lookup property.
When the linked document changes (the values are updated)
When a linked document is saved, deleted, or moved to the trash, AODocs automatically updates every document that links to it. Each dependent document re-reads the linked document and refreshes its lookup properties.
Updates run in the background, so the person editing the linked document is never blocked – even when thousands of documents link to it. The dependent documents are refreshed automatically within moments.
Administrators can also freeze lookup synchronization while a document is in specific workflow states; synchronization resumes when the document leaves those states. See Configure lookup properties in a document class.
When the linked document is deleted
If the linked document is deleted or trashed, every document that links to it has its lookup properties cleared, and the link is flagged as no longer resolving.
Note: Deleting the linked document is allowed (the values are cleared). Deleting the linked class or the linked property is blocked while a lookup depends on it.
Interactions with other features
- Always read-only. Lookup properties are maintained by the system. No one can edit them, including the columns of a looked-up table.
- Calculated fields can use lookup values. Because lookups resolve first, a formula can build on a pulled value.
- A link field can't be a workflow trigger and can't have a calculated value – the linked document must be chosen by a user, not computed.
- Search and views. Lookup property values are indexed like ordinary values, so documents are findable by their pulled values, and you can use lookup properties in views and filters.
- Copy and import. Copied or imported documents resolve their lookup properties on save, through the normal path.
Limits
| Item | Value |
| Documents a link field can point to | Exactly 1 (a single linked document). |
| Properties displayed when selecting a document | 4 maximum, including the title (title + up to 3). |
| Lookup properties per link field | No fixed limit. |
| Documents updated by one change to a linked document | No fixed limit – updated automatically in the background. |
| Update timing | Automatic, within moments – not guaranteed to be instantaneous. |
Troubleshooting
| Symptom | Cause / fix |
| The pulled values are empty | The link field may be empty, or the linked document may have been deleted. Re-open the document and pick the linked document again. |
| A value looks out of date | Updates run in the background. Wait a few moments and refresh; the value updates automatically after the linked document is saved. |
| You can't delete a document class or property | It's used by a lookup. The message reads "… is used as Lookup reference by: …". Remove the lookup configuration first. |
| A lookup property can't be added or saved | The lookup property's type must match the linked property's type (same type, and the same category or reference catalog). The configuration dialog creates matching properties for you. |