How to maintain history of changes in mapping?

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I have a mapping variable in my solidity code which maps address to name. I want to maintain the history/log of every change that happens in this mapping. What is the best possible solution to it?






solidity contract-development mapping logs history







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    I have a mapping variable in my solidity code which maps address to name. I want to maintain the history/log of every change that happens in this mapping. What is the best possible solution to it?






    solidity contract-development mapping logs history







    share|improve this question























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      I have a mapping variable in my solidity code which maps address to name. I want to maintain the history/log of every change that happens in this mapping. What is the best possible solution to it?






      solidity contract-development mapping logs history







      share|improve this question













      I have a mapping variable in my solidity code which maps address to name. I want to maintain the history/log of every change that happens in this mapping. What is the best possible solution to it?






      solidity contract-development mapping logs history




      solidity contract-development mapping logs history






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      Gagan

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          Define a change event like 



          event MyMapChange(address _addr, string _newName);


          and then, on each change, emit one like this:



          emit MyMapChange(myAddr, myNewName);


          Events get stored on the blockchain and can be queried, i.e. you can request request history, and also you can subscribe to new events, and even filter them by field values. To enable field filtering, you need to add indexed keyword to no more than 3 of the fields defined in your event, like this:



          event MyMapChange(address indexed _addr, string _newName);


          Check this related question and answers: How can I view event logs for an ethereum contract?






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            Define a change event like 



            event MyMapChange(address _addr, string _newName);


            and then, on each change, emit one like this:



            emit MyMapChange(myAddr, myNewName);


            Events get stored on the blockchain and can be queried, i.e. you can request request history, and also you can subscribe to new events, and even filter them by field values. To enable field filtering, you need to add indexed keyword to no more than 3 of the fields defined in your event, like this:



            event MyMapChange(address indexed _addr, string _newName);


            Check this related question and answers: How can I view event logs for an ethereum contract?






            share|improve this answer
























              up vote
              2
              down vote













              Define a change event like 



              event MyMapChange(address _addr, string _newName);


              and then, on each change, emit one like this:



              emit MyMapChange(myAddr, myNewName);


              Events get stored on the blockchain and can be queried, i.e. you can request request history, and also you can subscribe to new events, and even filter them by field values. To enable field filtering, you need to add indexed keyword to no more than 3 of the fields defined in your event, like this:



              event MyMapChange(address indexed _addr, string _newName);


              Check this related question and answers: How can I view event logs for an ethereum contract?






              share|improve this answer






















                up vote
                2
                down vote










                up vote
                2
                down vote









                Define a change event like 



                event MyMapChange(address _addr, string _newName);


                and then, on each change, emit one like this:



                emit MyMapChange(myAddr, myNewName);


                Events get stored on the blockchain and can be queried, i.e. you can request request history, and also you can subscribe to new events, and even filter them by field values. To enable field filtering, you need to add indexed keyword to no more than 3 of the fields defined in your event, like this:



                event MyMapChange(address indexed _addr, string _newName);


                Check this related question and answers: How can I view event logs for an ethereum contract?






                share|improve this answer












                Define a change event like 



                event MyMapChange(address _addr, string _newName);


                and then, on each change, emit one like this:



                emit MyMapChange(myAddr, myNewName);


                Events get stored on the blockchain and can be queried, i.e. you can request request history, and also you can subscribe to new events, and even filter them by field values. To enable field filtering, you need to add indexed keyword to no more than 3 of the fields defined in your event, like this:



                event MyMapChange(address indexed _addr, string _newName);


                Check this related question and answers: How can I view event logs for an ethereum contract?







                share|improve this answer












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                share|improve this answer










                answered 3 hours ago









                Utgarda

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