We are aware of this behaviour and we have an issue in the roadmap (BKNDLSS-16903 for reference) to implement the proper merge of accounts. Unfortunately, this is not of high priority currently, so the work on it has not started yet. I’ll check if we can raise the priority if this is critical for your app.
By the way, the reverse scenario already works - which is registering via some social network and after that registering in Backendless. In this case the accounts will be merged properly and the user will be able to login both ways afterwards. So probably you could use this workaround for now instead.
Thank you for your answer, unfortunately it’s enough important for my application.
If I understand correct I’ll need to take off “identity” for “email” field in user table then I will be able save two account with one email…
Can you say how I can create field with autoincrement?
The only way to implement autoincrement is to have a beforeCreate handler which would do that programatically. You’ll need to have a counter incremented in the code and set to the ID column of your choice.