How do we do this in EOSIO multi_index table? Want to define a table with an auto increment primary key id.
Have a look to available_primary_key in the EOS documentation, multi indexes do support auto increment keys.
You check the way monstereos did. They have table st_pet_config define last_id start with 0 and everytime you create new pet last_id increase https://github.com/leordev/monstereos/blob/master/contracts/pet/pet.hpp#L85
The two answers to this question are links to external sites that are now broken. this is why answers that are links are frowned upon, links break and therefore your answer breaks. to actually auto increment the primary key say your multi index uses a
uint64_t as its id. When emplacing into the table set the id like so.
row.column_name = table_name.available_primary_key();