Column type non-native after concatenation and thus "Output type mapping is missing for column" issue in DB Write node


I concatenated 2 data sets. In the 1st data set I have a column A with the type integer but in the 2nd set this column A is empty and thus identified as string. Unfortunately after the concatenation of the 2 data sets the column A has the type non-native [interface] and thus I got an error message when I tried to write these data in a database table.

Is there a way to solve my issue perhaps to automatically get the column type integer for my column A (in my 2nd data set the column is empty and thus every column type would be fine) or can I set all the column of non-native type to string (the most generic type) after a concatenation.

Is non-native the default column type in case of type conflict in the concatenation node?

Thank you for your help and best regards,


Hi @claudeostermann , does your problem get resolved if you follow your Concatenation node with a Column Auto Type Cast node, and then take your dataflow from the upper output port. This node should rescan sample and try to re-determine the data types ?


Hello @claudeostermann,

No. From node description:
…if the column types differ the column type is the common base type of both input column types…

So Int and Double should result in Double while String + Numeric column should result in Non-Native.

Apart from above mentioned Column Auto Type Cast node which should convert your column A to integer you can check Table Validator (Reference) and Table Validator nodes. They can also convert your columns and make sure your table structure is as expected before any DB operation.


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Thank you for the hint about the Column Auto Type Cast node. It perfectly fits my expectations.
I will also check the Table Validator (Reference) and Table Validator nodes.

Thanks again,



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