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Questions and Answers
In DynamoDB, what is the primary purpose of the partition key in both a simple primary key and a composite key?
In DynamoDB, what is the primary purpose of the partition key in both a simple primary key and a composite key?
- To uniquely identify each item in the entire table.
- To distribute data across different partitions for scalability. (correct)
- To define the order in which items are stored within a partition.
- To provide an alternative identifier for querying items.
A DynamoDB table uses UserID as the partition key. Which of the following scenarios warrants the addition of a sort key to form a composite key?
A DynamoDB table uses UserID as the partition key. Which of the following scenarios warrants the addition of a sort key to form a composite key?
- When the table size is expected to exceed DynamoDB's partition limit.
- When all items in the table must be uniquely identifiable by `UserID` alone.
- When frequent range-based queries on `UserID` are required.
- When multiple items can have the same `UserID`, requiring further differentiation. (correct)
When designing a DynamoDB table to store user activity logs, where each user can have multiple log entries, which key structure is most appropriate?
When designing a DynamoDB table to store user activity logs, where each user can have multiple log entries, which key structure is most appropriate?
- Simple primary key using a timestamp as the partition key.
- Composite key with timestamp as the partition key and `UserID` as the sort key.
- Simple primary key using `UserID` as the partition key.
- Composite key with `UserID` as the partition key and timestamp as the sort key. (correct)
Consider a DynamoDB table with a composite key consisting of GameID (partition key) and Score (sort key). How does DynamoDB ensure uniqueness in this table?
Consider a DynamoDB table with a composite key consisting of GameID (partition key) and Score (sort key). How does DynamoDB ensure uniqueness in this table?
In DynamoDB, what is a key difference in how data is stored and accessed when using a simple primary key versus a composite key?
In DynamoDB, what is a key difference in how data is stored and accessed when using a simple primary key versus a composite key?
A developer needs to store configuration settings for multiple applications in DynamoDB. Each application has a unique ID, and settings are versioned. Which key structure should they use?
A developer needs to store configuration settings for multiple applications in DynamoDB. Each application has a unique ID, and settings are versioned. Which key structure should they use?
You are designing a DynamoDB table for an e-commerce platform to store product reviews. Each product can have multiple reviews. Which key structure is most suitable?
You are designing a DynamoDB table for an e-commerce platform to store product reviews. Each product can have multiple reviews. Which key structure is most suitable?
In DynamoDB, you define a table with a composite key where CustomerID is the partition key and OrderDate is the sort key. What type of queries can be efficiently performed?
In DynamoDB, you define a table with a composite key where CustomerID is the partition key and OrderDate is the sort key. What type of queries can be efficiently performed?
Flashcards
Primary Key
Primary Key
Identifies items in a DynamoDB table, can be simple or composite.
Simple Primary Key
Simple Primary Key
Primary key using only a partition key (hash key).
Partition Key (Hash Key)
Partition Key (Hash Key)
The main key, its value must be unique across the table, and its value determines the item's partition.
Composite Key
Composite Key
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Sort Key (Range Key)
Sort Key (Range Key)
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Simple Key Use Case
Simple Key Use Case
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Composite Key Use Case
Composite Key Use Case
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Simple Key Example
Simple Key Example
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Study Notes
- Primary Key and Composite Key are used in AWS DynamoDB to uniquely identify items in a table
Primary Key
- Can be either simple or composite
- Simple Primary Key consists of a partition key (hash key)
- Each item in the table has a unique value for the partition key
- DynamoDB uses the partition key to distribute data across different partitions
- Partition Key (hash key) is the main key, and must be unique across the table
- DynamoDB uses the partition key to compute the partition where the item is stored
- Example:
UserID
Composite Key
- Is a type of primary key that consists of two attributes - partition key and sort key
- Partition Key is the hash key
- Sort Key (range key) helps to uniquely identify items within the same partition
- Items with the same partition key can have different sort key values
- Allows for more complex querying and sorting
- The partition key and sort key combination creates a unique key for each item in the table
- Able to have multiple items with the same partition key but a different sort key
- Example:
UserID(Partition Key) andOrderID(Sort Key)
Key Differences
- Simple Primary Key uses only the partition key (hash key) to uniquely identify each item
- Use case: Simple tables where each item needs unique identification via a single key (e.g., user ID)
- Composite Key uses both a partition key (hash key) and a sort key (range key) to uniquely identify each item
- Use case: When storing multiple items with the same partition key but needing an additional level of uniqueness (e.g., storing multiple orders for the same user)
Example Use Case
- Primary Key (Simple): Storing user details in a table, where
UserIDis the partition key. - Composite Key: Storing orders placed by a user, where
UserIDis the partition key andOrderIDis the sort key, allowing multiple orders for each user.
Summary
- Primary Key (simple) = Partition Key
- Composite Key = Partition Key + Sort Key
- If there is a composite key, then the simple primary key can have duplicates
- Keys are only defined at the creation of the table
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Description
The primary key in DynamoDB can be simple (partition key) or composite (partition and sort key). The partition key distributes data across partitions, while the sort key helps to uniquely identify items within the same partition, enabling complex queries.
