DEA-C01 Practice Question 41: Glue ResolveChoice Ambiguous Type

resolveChoice "resolves a choice type within this DynamicFrame and returns the new DynamicFrame", and the action chosen decides the shape of the result. The cast:{type} action "attempts to cast all values to the specified type", so cast:double converts the quoted strings into doubles and leaves the already-numeric values alone. The result is a single order_total column typed double, exactly what the curated Parquet table and the Athena schema require.

Option B produces the wrong shape. make_cols "converts each distinct type to a column with the name {columnName}_{type}", so the output would carry order_total_double and order_total_string side by side. The ambiguity is flattened rather than resolved, and every downstream query would have to coalesce two columns.

Option D has the same problem in a different form. make_struct "resolves a potential ambiguity by using a struct to represent the data"; each row gets a structure containing both an int/double and a string member. That is one column, but it is a struct, not a double.

Option A changes only metadata. The Data Catalog would claim the column is double, while the underlying files still contain quoted values and the DynamicFrame still reads a choice type. The job keeps failing, and if it did not, Athena would return nulls or errors for the quoted rows. (resolveChoice does offer a match_catalog action that casts each ChoiceType to the catalog's type, but that is a transformation on the data, not a crawler setting.)

Reference: DynamicFrame class - resolveChoice