Cast Nested Column

It lets the user cast the data type of any nested or struct type column from one type to another.

This transformation expects user to provide below inputs:

Input Arguments	Mandatory	Default Value	Description
column-name	Yes	-	The name of the nested or struct column
ddl	Yes	-	The new Data Definition Language (DDL) for the column

For example, consider we have below restonomer response in json:

{
  "col_A": "val_A",
  "col_B": {
     "col_C": "val_C",
     "col_D": 5
  }
}

Now, there is no direct way to cast the data type of col_D from Long to String. But it can be easily done using the CastNestedColumn transformation.

User can configure the CastNestedColumn transformation in the below manner:

{
  type = "CastNestedColumn"
  column-name = "col_B"
  ddl = "col_C STRING, col_D STRING"
}

The transformed response will now have the data type of col_D as String:

{
  "col_A": "val_A",
  "col_B": {
     "col_C": "val_C",
     "col_D": "5"
  }
}