[TYPO3-mvc] Properties from related objects with M:M

[Jochen Rau]

Hi Peter.

On 26.03.10 09:36, Peter Niederlag wrote:
>> Background: I have implemented the detection of the type of relation
>> at a point in time where Reflection part of FLOW3 wasn't available in
>>   Extbase. So, I had to parse the TCA to detect the type.
>
> That makes some things a lot more clear for me. ;) I was already quite
> puzzled that TCA has influence on the behaviour of querying the
> Model/Repository, when I ran into http://forge.typo3.org/issues/show/6933 .
>
>> [...] But there is a difference between the type of relation and the
>> way how this relation is stored in the database. ATM Extbase don't
>> differentiate the both.
>
> But, how's the roadmap now on this? IMO it would be very cool to use
> reflection and annotations to get the type of relation.
>
> But still then extbase doesn't quite know enough to find out about a
> ..csv foreign_key or _mm implementation if I understand this correct. So,
> how does the current implementation behave?

In the current implementation the type of relation is determined by the 
TCA definition of the column.

foreign_table set -> There is a relation
MM or foreign selector set -> RELATION_HAS_AND_BELONGS_TO MANY
foreign_field -> RELATION_HAS_MANY
foreign_field and maxitems=1 -> RELATION_HAS_ONE

But this will change for Extbase 1.2 I am currently working on. See:
http://forge.typo3.org/issues/show/7067

There will be a difference between single and multivalue properties. 
This will be determined only by the property annotation: array, 
SplObjectStorage Tx_Extbase_Persistence_ObjectStorage results in 
multivalue=TRUE, all others in multivalue=FALSE.

In addition Extbase hase to distinguish the technical solutions to store 
the relation data. This is determined by parsing the TCA definitions.

Regards
Jochen