storedKeyColumns

The primary table's key columns (partitionKeyColumns + clusteringKeyColumns) that the lookup table stores as plain columns next to indexColumn, in that order. When the indexed column is itself one of those key columns (@LookupIndex on a @ClusteringKey or @PartitionKey), it is already the lookup table's own key and is left out here, so the lookup DDL and INSERT name it once. GH #187: listing it twice produced CREATE TABLE ... (request_id UUID, user_id UUID, request_id UUID, ...), which the database rejects.