[TYPO3-v4] Virtual TCA fields

[Christian Kuhn]

Francois Suter wrote:
> What would it take in your opinion to add "virtual" fields to the TCA. I 
> mean fields that would be rendered in TCEforms, based on their TCA 
> configuration, but that would not have a database counterpart.

We occasionally need this for things like a checkbox that says: "Search 
for news-tags in news-bodytext and write to mm table when record is 
saved". This is usually done only once for a record. A processDatamap 
hook then does the magic and unsets the checkbox field to 0 on save.

Until now we always added dummy fields to the database. It's possible to 
prevent saving to a field in tcemain, but other modules fail.

In TCA maybe a key like "excludeFromDB" on fieldname or config level 
would be nice, but that might break extensions which are fiddling with TCA.

Christian