How to add databases to smart contract?

Question

I creating dApp and I want to add some sort of registration pannel(add nickname to wallet address) and its nessesary to store this data on db (public wallet address, nickname, email(optionally)). So can I make a function which can add this feature?

Answer 1

If you have somewhat complex data that you expect to be used mostly every time I would suggest mapping address to an object.

Declare the object:

struct registration = {
    string nickname; 
    string email;
}

Then create the mapping:

mapping(address -> registration) database;

You can set the data by calling:

database[targetAddress].nickname = newNickname;
database[targetAddress].email = newEmail; // leave black to keep the initialization value ""

Or

database[targetAddress] = registration(newNickname, newEmail);
database[targetAddress] = registration(newNickname, ); // if you wanted to initialize to "" in this case