+++
title = "Retail Cart References"
chapter = false
weight = 1
+++


## How to tackle this challenge

**What are the access patterns?**

The access patterns in the scenario are:

1. Insert and update items placed in a cart by users.
2. Return items related to a user (*AccountID*), sorted by *CreateTimestamp*, and scoped to a specific *Status*.
3. Return items across user by *ItemSKU*, sorted by *CreateTimestamp*, and scoped to a specific *Status*.
4. Offline ad hoc queries for Business Intelligence team.

Identify possible partition keys to fulfill the primary access pattern:

- What item attribute scales in volume along with higher access?
- What is a natural organization for the related data items (so as to return collected items relative to the access patterns above)?
- Consider the dimension of access: both reads and writes.

When determining how to organize items related to the primary access pattern:

- What organization needs to be written to return items in sorted order (sort by)?
- What is the hierarchy of the relationships (most general to more specific)?

Fulfilling the second, third, and fourth access patterns:

- The second and third access patterns are OLTP access patterns and can be modeled directly in DynamoDB.
- The fourth access pattern is OLAP and does not need to be fulfilled directly on DynamoDB, or in your solution for that matter.

#### Helpful references

Given the above, see below for some helpful references.
- **[Best Practices for Using Sort Keys to Organize Data](https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/bp-sort-keys.html)**
- **[Working with Queries in DynamoDB](https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Query.html)**
- **[Using Global Secondary Indexes in DynamoDB](https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/GSI.html)**
- **[How to perform advanced analytics and build visualizations of your Amazon DynamoDB data by using Amazon Athena](https://aws.amazon.com/blogs/database/how-to-perform-advanced-analytics-and-build-visualizations-of-your-amazon-dynamodb-data-by-using-amazon-athena/)**