Key-value and document store model in DynamoDB - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a key-value store in the context of databases?

A key-value store is a type of database that stores data as a collection of key and value pairs. Each key is unique and is used to retrieve the associated value quickly.

beginner

How does a document store differ from a key-value store?

A document store is a type of key-value store where the value is a complex document, often in JSON format, allowing nested data and richer queries compared to simple key-value pairs.

beginner

In DynamoDB, what is the role of the partition key?

The partition key, as part of the primary key (with an optional sort key), uniquely identifies each item in a DynamoDB table and determines the partition where the data is stored, enabling fast data retrieval.

intermediate

Why are key-value and document stores considered flexible for developers?

Because they allow storing data without a fixed schema, developers can easily add or change data structures without redesigning the database.

beginner

Give a real-life example of when to use a key-value store.

A key-value store is great for caching user session data in a web app, where each session ID (key) maps to session details (value) for quick access.

What does a key in a key-value store represent?

A A complex document with nested data

B A unique identifier to find data

C A fixed schema for data

D A type of database index

In key-value stores, the key is a unique identifier used to retrieve the associated value quickly.

Which data format is commonly used in document stores like DynamoDB?

A Plain text

B CSV

C XML

D JSON

Document stores often use JSON format to store complex, nested data structures.

What is a main advantage of using a document store over a relational database?

A Allows flexible, schema-less data

B Requires fixed schema

C Supports complex joins

D Slower data retrieval

Document stores allow flexible, schema-less data storage, making it easier to evolve data models.

In DynamoDB, what determines where data is stored?

A Sort key

B Primary key

C Partition key

D Foreign key

The partition key determines the partition where the data is stored in DynamoDB.

Which scenario best fits using a key-value store?

A Caching session tokens for quick lookup

B Maintaining relational data with foreign keys

C Running complex SQL queries

D Storing user profiles with many fields

Key-value stores are ideal for caching session tokens because they provide fast access using unique keys.

Explain the difference between a key-value store and a document store.

Think about how simple or complex the stored data is.

Describe how DynamoDB uses keys to organize and retrieve data.

Focus on the role of partition and sort keys.