As part of your migration to BigQuery, you are tasked with deciding on the optimal data model for a table that stores transactional purchase information across multiple store locations. This table includes columns for the time of the transaction, items purchased, store ID, and the city and state in which the store is located. You often query this table to analyze the number of each item sold over the past 30 days and to examine purchasing trends broken down by state, city, and individual store. What data modeling approach would you take to ensure the best query performance for these types of analyses?