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Data sync between mobile app and cloud

Well I am building an app for both iOS and Android and both apps need to be in sync with MySQL cloud DB. Both apps work offline, so I need all the insert and update functionality. Delete will probably not be used, but still I would like to know.

Well, I'm looking here for a solution or ideas or algorithms to do for this.

I saved CreateOn and LastSync as a timestamp column for each table.

Now the problem is, should I always check all rows and all columns every time?

I think I should keep the ModifiedOn column in all tables and check that with LastSync for each device ID. What do you suggest?

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This may not be the answer you are looking for, but in a project I am working on, we are using Azure Mobile Services. There are Android and iOS SDKs where they have implemented synchronization between a standalone database and Azure (as with Git, you can call push and pull methods).



There are some limitations (TableStorage is MSSQL limited storage) but you should check that.

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I know this about two years overdue, but I did the same (Android app that syncs with web api and postgresql)

What I am doing so far (still researching if this is the best way how I found this question) is that I keep the last_update field with a timestamp when the data was last_updated and the modified field with a boolean whether the data has been changed (by user action on the device)

So when I do sync:



  • First I copy the database to the backup (in case of problem)
  • I am posting all lines marked as modified (server handles conflicts)
  • then remove them
  • after that i find the value max (last_update),
  • I subtract one minute from it
  • Then query for all rows that have been updated after this value (this will also include the data I submitted, because there is no way, unless there is a problem, that the row is set to change with last_update before the last unmodified row)

This can cause some duplicate data to be carried over (especially if you often make a lot of changes), but in my case this is a rare occurrence.

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