How to map an address with a string array in solidity?

Question

Goal: I wish to store an array of names with an address in a smart contract. It's more like Key-Value pairs where addresses are paired with a list of type strings.

Can I use mapping to implement this? See below for instance.

mapping(address => strings[]) userAddress2UserNames;

Or, there is a different approach to it?

Experiments I performed

I got no error when I compiled the above code but when I call a method which returns string[] from this mapping I got an error stated below.

TypeError: This type is only supported in the new experimental ABI encoder. Use "pragma experimental ABIEncoderV2;" to enable the feature.

I'm not much aware of this version but I am assuming I should not do production level implementation with it because may be it's not stable. (Please correct me if I am wrong)

Please suggest me a way to achieve my goal.

Answer 1

How long are the user names? Maybe you can use bytes32 instead of string (each username would be limited up to 32 chars). By doing this, you wouldn't be combining two levels of dynamic arrays, which is not permitted in the current version.

Answer 2

The compiler will generate automatically getters for variables declared as public.

mapping(address => strings[]) userAddress2UserNames;

In this case the getter will look like

function userAddress2UserNames(address _addr, uint _index);

You have to provide an address and index to the array.

Answer 3

As it is suggested by @Patricio use bytes instead of string.
At current versions there are many limitations on string use. So better use bytes.
What you want to achieve is One to many mapping. But mapping are unique and you can't map a key with many values, so you have to use struct in this case.
Follow the below link they have explained it very well.
https://ethereum.stackexchange.com/a/38842/24373