Is it possible to get the creation timestamp of a record of a Smart Contract Table?

Question

Usually in centralized apps we have the fields created_at and created_by to know when and who created this record and also sometimes modified_at and modified_by to register who and when was the last modification of a record.

How should we do that in our smart contracts? Should we have account_name and uint64_t added manually to the table or is there an easy way to find out through get actions?

Answer 1

Just add a created_at field to your table.

struct blog {
    uint64_t id;
    time created_at;

    uint64_t primary_key()const { return id; }
    EOSLIB_SERIALIZE(blog, (id)(created_at))
}
typedef multi_index<N(blog), blog> blog_index;
blog_index blogs;

When creating a record, set created_at to now().

blogs.emplace(_self, [&](auto& x) {
    x.id = blogs.available_primary_key();
    x.created_at = now();
}

Answer 2

If you need to know this information inside the smart contract, then you should store this information in the record just like you would in a regular DB.