topic Delta table definition - Identity column in Get Started Discussions

Delta table definition - Identity column

oleprince — Sat, 14 Oct 2023 16:03:23 GMT

Hello,

Would anyone know if it is possible to create a delta table using Python that includes a column that is generated by default as identity (identity column for which the value inserted can be manually overriden)?

There seems to be a way to create an identity column using Python (through Delta Lake api, using the DeltaTableBuilder) that is generated always as identity (using option "generatedAlwaysAs") but I havent found the equivalent "generatedByDefaultAs" option).

So far, the only way I've found in order to create a column that is generated by default as identity is through Spark SQL.

thanks

Re: Delta table definition - Identity column

gmiguel — Thu, 17 Oct 2024 16:29:22 GMT

Hi @oleprince ,

As far as I know, it's not possible yet to create tables with Identity columns using pyspark (DeltaTable api). You can create generated columns, but Identity columns are not allowed.
The only way to achieve this is through Spark Sql.

Re: Delta table definition - Identity column

Malthe — Mon, 28 Jul 2025 12:39:59 GMT

There is a `generatedByDefaultAs` option now, see https://github.com/delta-io/delta/pull/3404.