Question on behalf of @stefan-sparse-array:
Is there currently any way to use the expression language in an overview model?
Hej @ansgar-solar-lake, I have tried this before, and transient fields have not been computed before they were loaded into my overview. What additional settings are necessary in order to display computed transient fields in an overview?
Hi @eva-solid-surge, does these transient fields show up on the form engine beforehand? If they show up in the Form, by saving it, Data Services will try to persist the transient field (by default since 30.0) to its database. Then when loaded, these fields will always be filled in the document and ready to be displayed on the Overview Engine without any further configuration. See mgm.services.core.document.persistTransientFields in Data Services for more info.
A note is that this behavior only applies to the newly created document, for old/previous documents, you would need to provide some migration steps to persist these transient field to the database.
Thanks, @eva-solid-surge, for your note.
I had the wrong assumption that this works with transient fields in the overview and tree engine, but in fact it is not.
The approach, which is currently working is with persisted computed fields.
Answer on behalf of @stefan-cold-haze:
This is not possible at the moment.
Answer on behalf of @jennifer-tinted-cluster:
It is planned to make this possible in <INTERNAL_LINK>
Answer on behalf of @ansgar-solar-lake:
Alternatively the following approach might be an option:
- Add a transient field in the document model.
- Add a calculation for this field, which “compiles” the “expression”.
- Use this field for the overview column.
Note that transient means it is not persisted and not indexed, so sorting and filtering by this column is not possible.
You can also make the field persistent, then it would be indexed and filtering as well as sorting would work. But usually persisting is not wanted in such cases.