Hello There!
First of all, thank you very much for the library.
I have found the following problem in file Dapper.Oracle/BulkSql/BulkOperation.cs:
line 79: var dbType = map.DbType ?? OracleMapper.GuessType(obj.First().GetType());
In the above line OracleMapper.GuessType(obj.First().GetType()) does not work as expected, because obj.First().GetType() returns generic class type in place of property type. I think, it should be changed from "obj.First().GetType()" to "obj.Select(map.Property).ToArray().First().GetType()" which returns the required property type.
Thanks & Regards