How to upsert a relational database from kafka

[Uwe Geercken]

Hello,
 
I am looking for some advice or best practice: I want to update OR insert a 
relational database table from kafka messages. As in Kafka everything is an 
"insert", what is the best way to determine if I need to update or to insert 
the data?
 
Do I have to write some code (which would be ok)? But maybe there is something 
more straight ahead: can Kafka connect solve this?
 
I would be happy to get some guidance.
 
Rgds,
 
Uwe