Data-Engineer-Associate Amazon Web Services AWS Certified Data Engineer - Associate (DEA-C01) Free Practice Exam Questions (2026 Updated)

Option A is the correct answer because it meets the requirements with the least operational overhead. Creating an S3 event notification that has an event type of s3:ObjectCreated:* will trigger the Lambda function whenever a new object is created in the S3 bucket. Using a filter rule to generate notifications only when the suffix includes .csv will ensure that the Lambda function only runs for .csv files. Setting the ARN of the Lambda function as the destination for the event notification will directly invoke the Lambda function without any additional steps.

Option B is incorrect because it requires the user to tag the objects with .csv, which adds an extra step and increases the operational overhead.

Option C is incorrect because it uses an event type of s3:*, which will trigger the Lambda function for any S3 event, not just object creation. This could result in unnecessary invocations and increased costs.

Option D is incorrect because it involves creating and subscribing to an SNS topic, which adds an extra layer of complexity and operational overhead.

AWS Certified Data Engineer - Associate DEA-C01 Complete Study Guide, Chapter 3: Data Ingestion and Transformation, Section 3.2: S3 Event Notifications and Lambda Functions, Pages 67-69

Building Batch Data Analytics Solutions on AWS, Module 4: Data Transformation, Lesson 4.2: AWS Lambda, Pages 4-8

AWS Documentation Overview, AWS Lambda Developer Guide, Working with AWS Lambda Functions, Configuring Function Triggers, Using AWS Lambda with Amazon S3, Pages 1-5

Problem Analysis:

The company uses AWS Glue for ETL pipelines and must enforce data quality checks during pipeline execution.

The goal is to implement quality checks with minimal implementation effort.

Key Considerations:

AWS Glue provides an Evaluate Data Quality transform that allows for defining quality checks directly in the pipeline.

DQDL (Data Quality Definition Language) simplifies the process by allowing declarative rule definitions.

Solution Analysis:

Option A: SQL Transform

SQL queries can implement rules but require manual effort for each rule and do not integrate natively with Glue.

Option B: Evaluate Data Quality Transform + DQDL

AWS Glue’s built-in Evaluate Data Quality transform is designed for this use case.

Allows defining thresholds and rules in DQDL with minimal coding effort.

Option C: Custom Transform with PyDeequ

PyDeequ is a powerful library but adds unnecessary complexity compared to Glue’s native features.

Option D: Custom Transform with Great Expectations

Similar to PyDeequ, Great Expectations adds operational complexity and external dependencies.

Final Recommendation:

Use the Evaluate Data Quality transform with DQDL to implement data quality rules in AWS Glue pipelines.

AWS Glue Data Quality

DQDL Syntax and Examples

AWS Glue Studio Documentation

The company wants to ensure that no customer records are deleted or modified for 7 years, and even the root user should not have the ability to change the data. S3 Object Lock in Compliance Mode is the correct solution for this scenario.

Option B: Enable compliance mode on the S3 bucket. Use a default retention period of 7 years.In Compliance Mode, even the root user cannot delete or modify locked objects during the retention period. This ensures that the data is protected for the entire 7-year duration as required. Compliance mode is stricter than governance mode and prevents all forms of alteration, even by privileged users.

Option A (Governance Mode) still allows certain privileged users (like the root user) to bypass the lock, which does not meet the company ' s requirement. Option C (legal hold) and Option D (setting retention per object) do not fully address the requirement to block root user modifications.

The correct answer is to configure AWS Glue triggers to run the ETL jobs every hour and use AWS Glue connections to establish connectivity between the data sources and Amazon Redshift. AWS Glue triggers are a way to schedule and orchestrate ETL jobs with the least operational overhead. AWS Glue connections are a way to securely connect to data sources and targets using JDBC or MongoDB drivers. AWS Glue DataBrew is a visual data preparation tool that does not support MongoDB as a data source. AWS Lambda functions are a serverless option to schedule and run ETL jobs, but they have a limit of 15 minutes for execution time, which may not be enough for complex transformations. The Redshift Data API is a way to run SQL commands on Amazon Redshift clusters without needing a persistent connection, but it does not support loading data from AWS Glue ETL jobs. References:

AWS Glue triggers

AWS Glue connections

AWS Glue DataBrew

[AWS Lambda functions]

[Redshift Data API]

A data mesh approach in AWS typically uses Lake Formation for domain-level access control and Athena for cross-domain querying through federated views. CloudTrail ensures auditing.

“For data mesh architectures, use AWS Lake Formation for fine-grained access control and Athena views for cross-domain analysis. Enable CloudTrail to audit access.”

– Ace the AWS Certified Data Engineer - Associate Certification - version 2 - apple.pdf

This ensures scalability, security, and compliance across domains.

To optimize joins between large tables, Redshift recommends using KEY distribution on a common, high-cardinality join key to ensure co-location of data blocks. The Amazon Redshift Advisor identifies performance bottlenecks and provides recommendations for distribution and sort keys.

“Use KEY distribution when joining large tables on a common high-cardinality column. Use Redshift Advisor to identify query optimization opportunities.”

Problem Analysis:

The company uses AWS Glue for ETL pipelines and requires automatic data quality checks during pipeline execution.

The solution must integrate with existing AWS Glue pipelines and evaluate data quality rules based on predefined thresholds.

Key Considerations:

Ensure minimal implementation effort by leveraging built-in AWS Glue features.

Use a standardized approach for defining and evaluating data quality rules.

Avoid custom libraries or external frameworks unless absolutely necessary.

Solution Analysis:

Option A: SQL Transform

Adding SQL transforms to define and evaluate data quality rules is possible but requires writing complex queries for each rule.

Increases operational overhead and deviates from Glue ' s declarative approach.

Option B: Evaluate Data Quality Transform with DQDL

AWS Glue provides a built-in Evaluate Data Quality transform.

Allows defining rules in Data Quality Definition Language (DQDL), a concise and declarative way to define quality checks.

Fully integrated with Glue Studio, making it the least effort solution.

Option C: Custom Transform with PyDeequ

PyDeequ is a powerful library for data quality checks but requires custom code and integration.

Increases implementation effort compared to Glue ' s native capabilities.

Option D: Custom Transform with Great Expectations

Great Expectations is another powerful library for data quality but adds complexity and external dependencies.

Final Recommendation:

Use Evaluate Data Quality transform in AWS Glue.

Define rules in DQDL for checking thresholds, null values, or other quality criteria.

This approach minimizes development effort and ensures seamless integration with AWS Glue.

AWS Glue Data Quality Overview

DQDL Syntax and Examples

Glue Studio Transformations

DynamoDB Time to Live (TTL) automatically expires and deletes items based on a timestamp attribute — it requires minimal setup and runs without additional infrastructure.

The engineer only needs to define a TTL attribute (e.g., expiration_time) and set its epoch value when items are inserted.

“To automatically delete old items from a DynamoDB table, enable TTL and define a timestamp attribute. Items are removed automatically after the specified time with no extra maintenance.”

– Ace the AWS Certified Data Engineer - Associate Certification - version 2 - apple.pdf

This is serverless, free, and requires no scheduling or code-based cleanup.

AWS Lake Formation is specifically designed to simplify fine-grained access control for data lakes stored in Amazon S3. By using Lake Formation tag-based access control (LF-TBAC), administrators can define access policies once and apply them dynamically based on tags rather than managing individual IAM policies.

LF-Tags can be assigned to databases, tables, and columns in the AWS Glue Data Catalog. Departments are granted permissions based on tags, ensuring that each department can access only the data it is authorized to view. This approach scales efficiently as datasets and departments grow, which is critical for data lakes ingesting millions of records daily.

Managing IAM policies per department is operationally complex and error-prone. Redshift-based access centralization limits flexibility and introduces unnecessary infrastructure. Syncing data into an RDS database adds cost, latency, and maintenance overhead.

Lake Formation provides centralized governance, auditing, and least-privilege enforcement with minimal administrative effort, making it the optimal solution.

AWS Glue Data Catalog stores metadata about data stored in Amazon S3, including table schemas and partitions. If new partitions are added to S3 and the Glue Data Catalog is not updated—either through crawlers or explicit API calls—query engines such as Amazon Athena and AWS Glue will not be aware of the new data.

This leads to analysis results that appear incomplete or outdated, even though the underlying data exists in S3. This is a common issue in time-sensitive analytics workloads where data arrives frequently and partitions change often.

IAM permission issues would typically cause access failures rather than missing records. S3 versioning affects object history, not query visibility. Overlapping Glue job schedules could cause processing delays but would not directly cause missing data during query time.

Therefore, the most likely cause is that the Glue Data Catalog metadata is not synchronized with the latest S3 partitions.

To prevent unintentional file deletions and meet the requirement with minimal operational overhead, enabling S3 Versioning is the best solution.

S3 Versioning:

S3 Versioning allows multiple versions of an object to be stored in the same S3 bucket. When a file is deleted or overwritten, S3 preserves the previous versions, which means you can recover from accidental deletions or modifications.

Enabling versioning requires minimal overhead, as it is a bucket-level setting and does not require additional backup processes or data replication.

Users can recover specific versions of files that were unintentionally deleted, meeting the needs of the data engineer to avoid accidental data loss.

The correct answer is D: Enable native Amazon RDS database audit logging with CloudWatch and CloudTrail integration.

Native RDS database audit logging captures SQL-level activities, including which user is modifying data, which is essential for meeting audit requirements.

Amazon CloudWatch Logs can be used to centralize and store logs.

CloudTrail logs API calls related to instance-level changes, ensuring all modifications are traceable.

This approach provides a comprehensive audit trail and supports compliance with security governance policies.

“Enable and configure native Amazon RDS database audit logging. Enable Amazon CloudWatch Logs. Configure metric filters and alarms. Configure AWS CloudTrail audit logging.”

Problem Analysis:

The company uses DynamoDB for gaming data storage and needs to ingest data into Amazon OpenSearch Service in near real time.

Data updates must propagate quickly to OpenSearch for analytics or search purposes.

Key Considerations:

DynamoDB Streams provide near-real-time capture of table changes (inserts, updates, and deletes).

Integration with AWS Lambda allows seamless processing of these changes.

OpenSearch offers APIs for indexing and updating documents, which Lambda can invoke.

Solution Analysis:

Option A: Step Functions with Periodic Export

Not suitable for near-real-time updates; introduces significant latency.

Operationally complex to manage periodic exports and S3 data ingestion.

Option B: AWS Glue Job

AWS Glue is designed for ETL workloads but lacks real-time processing capabilities.

Option C: DynamoDB Streams + Lambda

DynamoDB Streams capture changes in near real time.

Lambda can process these streams and use the OpenSearch API to update the index.

This approach provides low latency and seamless integration with minimal operational overhead.

Option D: Custom OpenSearch Plugin

Writing a custom plugin adds complexity and is unnecessary with existing AWS integrations.

Implementation Steps:

Enable DynamoDB Streams for the relevant DynamoDB tables.

Create a Lambda function to process stream records:

Parse insert, update, and delete events.

Use OpenSearch APIs to index or update documents based on the event type.

Set up a trigger to invoke the Lambda function whenever there are changes in the DynamoDB Stream.

Monitor and log errors for debugging and operational health.

Amazon DynamoDB Streams Documentation

AWS Lambda and DynamoDB Integration

Amazon OpenSearch Service APIs

For near real-time processing of new files in S3, event-driven ingestion is optimal. S3 Event Notifications can trigger AWS Lambda to immediately load data into Amazon Redshift, eliminating latency associated with batch scheduling.

“Event-based triggers using S3 notifications and Lambda functions are effective for near real-time ingestion pipelines into Amazon Redshift.”

– Ace the AWS Certified Data Engineer - Associate Certification - version 2 - apple.pdf

Option C (Glue bookmarks) is best for batch jobs, and zero-ETL applies to Aurora to Redshift, not S3.

Option A (AWS DMS): Lets you replicate only selected tables from Aurora to Redshift. It supports ongoing replication (CDC) and reduces unnecessary data transfers.

Option C (Zero-ETL with Aurora to Redshift): This new integration allows real-time, serverless, and low-maintenance data replication. It ' s designed to reduce operational overhead drastically.

Other options introduce manual processing or inefficient query access (Option D). Glue workflows (Option E) add unnecessary complexity and lag for near-real-time needs.

“Zero-ETL integration between Amazon Aurora and Redshift enables real-time analytics without building complex pipelines.”

The optimal solution for near-real-time querying and visualization of logs is to integrate Amazon CloudWatch Logs with Amazon OpenSearch Service using subscription filters, which stream the logs directly into OpenSearch for querying and dashboarding:

“Use OpenSearch Service with CloudWatch Logs and create a subscription filter to stream log data in near real time into OpenSearch. Then use OpenSearch dashboards for visualization.”

– Ace the AWS Certified Data Engineer - Associate Certification - version 2 - apple.pdf

This approach offers low latency and avoids batch exports, unlike the scheduled Athena + S3 pattern.

Amazon Athena charges per amount of data scanned by each query. When the same query with identical parameters is executed multiple times, re-scanning the data repeatedly increases both cost and execution time. Athena provides query result reuse, which allows previously computed query results to be reused when an identical query is rerun within a configurable time window.

By enabling query result reuse at the Athena workgroup level, Athena automatically returns cached results instead of re-reading data from Amazon S3. This significantly improves query performance while reducing data scan costs. This feature is specifically designed for workloads where analysts frequently rerun complex queries with the same parameters, which directly matches the scenario.

Converting data to JSON would degrade performance because JSON is not a columnar format and increases scan size. Using Amazon EMR introduces unnecessary infrastructure management and cost for a query optimization problem that Athena already solves natively. Amazon Redshift Spectrum is intended for querying S3 data from within Redshift and does not address repeated-query optimization in Athena.

Therefore, configuring query result reuse in the Athena workgroup is the most cost-effective and operationally efficient solution.

AWS Glue is a fully managed service that provides a serverless data integration platform for data preparation, data cataloging, and data loading. AWS Glue Studio is a graphical interface that allows you to easily author, run, and monitor AWS Glue ETL jobs. AWS Glue Data Quality is a feature that enables you to validate, cleanse, and enrich your data using predefined or custom rules. AWS Step Functions is a service that allows you to coordinate multiple AWS services into serverless workflows.

Using the Detect PII transform in AWS Glue Studio, you can automatically identify and label the PII in your dataset, such as names, addresses, phone numbers, email addresses, etc. You can then create a rule in AWS Glue Data Quality to obfuscate the PII, such as masking, hashing, or replacing the values with dummy data. You can also use other rules to validate and cleanse your data, such as checking for null values, duplicates, outliers, etc. You can then use an AWS Step Functions state machine to orchestrate a data pipeline to ingest the data into the S3 data lake. You can use AWS Glue DataBrew to visually explore and transform the data, AWS Glue crawlers to discover and catalog the data, and AWS Glue jobs to load the data into the S3 data lake.

This solution will meet the requirement with the least operational effort, as it leverages the serverless and managed capabilities of AWS Glue, AWS Glue Studio, AWS Glue Data Quality, and AWS Step Functions. You do not need to write any code to identify or obfuscate the PII, as you can use the built-in transforms and rules in AWS Glue Studio and AWS Glue Data Quality. You also do not need to provision or manage any servers or clusters, as AWS Glue and AWS Step Functions scale automatically based on the demand.

The other options are not as efficient as using the Detect PII transform in AWS Glue Studio, creating a rule in AWS Glue Data Quality, and using an AWS Step Functions state machine. Using an Amazon Kinesis Data Firehose delivery stream to process the dataset, creating an AWS Lambda transform function to identify the PII, using an AWS SDK to obfuscate the PII, and setting the S3 data lake as the target for the delivery stream will require more operational effort, as you will need to write and maintain code to identify and obfuscate the PII, as well as manage the Lambda function and its resources. Using the Detect PII transform in AWS Glue Studio to identify the PII, obfuscating the PII, and using an AWS Step Functions state machine to orchestrate a data pipeline to ingest the data into the S3 data lake will not be as effective as creating a rule in AWS Glue Data Quality to obfuscate the PII, as you will need to manually obfuscate the PII after identifying it, which can be error-prone and time-consuming. Ingesting the dataset into Amazon DynamoDB, creating an AWS Lambda function to identify and obfuscate the PII in the DynamoDB table and to transform the data, and using the same Lambda function to ingest the data into the S3 data lake will require more operational effort, as you will need to write and maintain code to identify and obfuscate the PII, as well as manage the Lambda function and its resources. You will also incur additional costs and complexity by using DynamoDB as an intermediate data store, which may not be necessary for your use case. References:

AWS Glue

AWS Glue Studio

AWS Glue Data Quality

[AWS Step Functions]

[AWS Certified Data Engineer - Associate DEA-C01 Complete Study Guide], Chapter 6: Data Integration and Transformation, Section 6.1: AWS Glue