Assumes that the table is a char field, but when the new is not allowed to repeat,

I can check the first, whether to have new record of "ABC", is not new, have jumped over, but the data more efficiency is very low, so is there a contact database only once judgment will be finished after the new method?

CodePudding user response:

AddOrUpdate

CodePudding user response:

Meger Oracle SQL server is available, EF if not write their own one