Allow onUpdate in install

[michsk]

I would like to suggest to add onUpdate parameter to Magento\Framework\DB\Ddl\Table::addForeignKey we now can only add onDelete

[mazhalai]

@Michal-sk Thank you for your suggestion, we have created MAGETWO-42066 to track this request.

[akaplya]

Hi, this is deliberate restriction, to achieve better compliance with other possible database engines.
But you can implement actions like "ON UPDATE" on application level. In this case your code will be compatible with Magento SPI ( events, interceptors, e.t.c).

[piotrekkaminski]

Hello. We decided against this one and also remove existing cascades for performance reasons wherever we could.

[michsk]

No problem, im actually removing it from other projects as well.