I want to save name in table, and to search by it. It doesn't seems that it is possible to have secondary index with type name for some reason. I would like also to pass name in function and to have require_auth() on that name parameter. So the question would be, can i somehow convert that name to uint64_t so I can store it and have index on it?


1 Answer 1


This is the functionality that the multi index was based around.

To get the name, simple add .value to your key on return:

uint64_t primary_key() const { return key.value;} // key.VALUE

In the tutorial, they actually use a uint64_t for the secondary index. That's all eosio::name is under the hood, a uint64_t. Granted they use it to represent an age by a number, but it's still the same type nonetheless.


uint64_t age;
uint64_t get_secondary_1() const { return age;} // secondary index

typedef eosio::multi_index<"people"_n, person, 
indexed_by<"byage"_n, const_mem_fun<person, uint64_t, &person::get_secondary_1>>
  > address_index;

In this tutorial, you can see the primary index is indeed an eosio::name type:

struct person {
 name key;
 std::string first_name;
 std::string last_name;
 std::string street;
 std::string city;
 std::string state;

 uint64_t primary_key() const { return key.value;}
  • 1
    i was missing this "conversion" between name and uint64_t, by using .value! Thanks for pointing me to right direction
    – Bida
    Commented Dec 18, 2018 at 14:27
  • Oh yeah, I should have added that. Thank you for reminding me!
    – Nat
    Commented Dec 18, 2018 at 14:44

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