AWS Certified Developer - by Christophe Limpalair

Question 1

Do partition keys always have to be unique?

Answer 1

Only for simple primary keys (when we only have a partition key and no sort key). If we have a composite key (partition + sort key), then the partition key does not have to be unique as long as the sort key is.

Question 2

When can DynamoDB secondary indexes be created?

Answer 2

Local secondary indexes must be created at table creation, while Global secondary indexes can be created on a table that already exists.

Question 3

What request is required to put all parts of a file together when using multi-part upload?

Answer 3

The “complete” request

Question 4

What three different versioning states can a bucket have?

Answer 4

Unversioned (the default)
Versioning-Enabled
Versioning-Suspended

Question 5

Can we enable versioning for specific objects?

Answer 5

No, object versioning is done at the bucket level, not the object level.

Question 6

How can you give your code permissions to query AWS services when running outside of the AWS environment?

Answer 6

Access keys (access key ID and secret access key)

Question 7

What are some main differences between Local Secondary Indexes and Global Secondary Indexes?

Answer 7

LSIs share read/write capacity with the parent table. They also use the same partition key, but give the ability to have different sort keys. LSIs support strongly consistent reads.

GSIs have separate read/write capacity than the parent table. They provide the ability to have different partition keys AND sort keys. GSIs do not support strongly consistent reads, only eventually consistent.

Question 8

Can versioning be enabled on buckets that already have objects in them?

Answer 8

Yes. Those objects already in the bucket will receive a Version ID of null.

Question 9

How can we set the Version ID for objects in S3?

Answer 9

We don’t. This is automated by S3. In fact, we can’t even edit the Version ID.

Question 10

What happens if you delete a versioned object?

Answer 10

You will get a 404 Not Found error if you try to retrieve it, but you can still specify an existing Version ID to retrieve specific versions.

Question 11

What happens if you delete a specific version of an object with its Version ID?

Answer 11

That version is no longer in your bucket but you can still access the latest version without receiving a 404 Not Found error.

Question 12

What are some key characteristics of local secondary indexes?

Answer 12

Local secondary indexes have the same partition key as the parent table, but different sort keys. LSIs share read/write capacity units with the parent table.

Question 13

What is the best way to give your code permissions to access other AWS services when running on EC2 instances?

Answer 13

IAM roles

Question 14

In DynamoDB, what are the two different kinds of primary keys?

Answer 14

• Partition key (Simple primary key)
• ## Partition key and sort key (Composite key)Previously known as (but could still be on the exam):
• Hash key
• Hash key and range key

Question 15

Each AWS accounts can own how many buckets?

Answer 15

100

Question 16

To enable encryption at rest on Amazon S3, we must use keys created and managed by AWS.

Answer 16

False. We also have the option to create and manage our own keys.

Question 17

At what size file should you use multi-part upload?

Answer 17

100mb

Question 18

What is true about DynamoDB?

Answer 18

DynamoDB uses optimistic concurrency control, and DynamoDB uses conditional writes for consistency.

Question 19

Can you completely disable versioning once it’s enabled?

Answer 19

No, you can only suspend versioning. This will make it so that any newly uploaded object will receive a Version ID of null. Other versions will remain in the bucket.

Question 20

What are some key characteristics of global secondary indexes?

Answer 20

Global secondary indexes can be created on tables that already exist. They can have different partition keys and sort keys. GSIs have separate read/write capacity units.