Why there is not primary key flag for a table?

[foobarrer]

Is your feature request related to a problem? Please describe.

I make a mysql sink function for write the data from kafka to mysql

When use the dataStream API , Why there is not primary key in the captured data it's quiet a big problem for me, cuz I can't do some action like update or delete in the target mysql table by a unique key besides for current version of flink cdc, the table that has been captured by flink cdc must have a primary key,

Describe the solution you'd like

I think it's a good idea to have the primary key flag in date captured data like below

Describe alternatives you've considered No