CODEWITHSUNDEEP
soliditysmartcontracts
sultan
sultan

Reputation: 419

ERC721. How to add additional information related to property using erc721 standard

I'm not having so much experience with ERC721 token standard, currently I'm working on a real-estate DAPP. I have a question. if I want to add external information related to a specific property like Location, Price, property number etc. every time if a new property register, what will be the best way to do that..?? but I don't want this with solidity Struct, is it possible to extend the ERC721 Metadata Interface Contract?? or any other solution??

I have tried almost everything but I think I'm missing something.

Upvotes: 2

Views: 1590

Answers (2)

Stephen Hodgkiss
Stephen Hodgkiss

Reputation: 21

Please see this post where I finally found a solution. It includes a sample implementation for both ERC20 and ERC721, forked from an implementation of Kaleido's Firefly and amended to cater for the mentioned Real Estate dApp. Hope it helps someone.

https://ethereum.stackexchange.com/questions/139698/example-adding-custom-data-to-erc20-token-transfer/

Upvotes: 0

Petr Hejda
Petr Hejda

Reputation: 43491

If you want to store the data on-chain, a mapping (uint256 => Property), where the uint256 is the token ID and Property is "struct(location, price, ...)", containing the data is probably the cheapest option gas-wise.

But since your question states you don't want to use struct, you can chose to store the data on-chain with a series of mappings:

mapping (uint256 => string) tokenIdToLocation;
mapping (uint256 => uint64) tokenIdToUsdPrice;
// etc.

You can also decide to store the data off-chain, and link to this storage from your contract. In that case, you'd implement the tokenURI() function of the ERC721Metadata interface (both defined in the ERC-721 standard). The tokenUri() would return a (string) URL of an off-chain resource where you can display the (off-chain) data.

Upvotes: 6

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