Data Engineers
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πŸ’» How to Become a Data Engineer in 1 Year – Step by Step πŸ“ŠπŸ› οΈ

βœ… Tip 1: Master SQL & Databases
- Learn SQL queries, joins, aggregations, and indexing
- Understand relational databases (PostgreSQL, MySQL)
- Explore NoSQL databases (MongoDB, Cassandra)

βœ… Tip 2: Learn a Programming Language
- Python or Java are the most common
- Focus on data manipulation (pandas in Python)
- Automate ETL tasks

βœ… Tip 3: Understand ETL Pipelines
- Extract β†’ Transform β†’ Load data efficiently
- Practice building pipelines using Python or tools like Apache Airflow

βœ… Tip 4: Data Warehousing
- Learn about warehouses like Redshift, BigQuery, Snowflake
- Understand star schema, snowflake schema, and OLAP

βœ… Tip 5: Data Modeling & Schema Design
- Learn to design efficient, scalable schemas
- Understand normalization and denormalization

βœ… Tip 6: Big Data & Distributed Systems
- Basics of Hadoop & Spark
- Processing large datasets efficiently

βœ… Tip 7: Cloud Platforms
- Familiarize with AWS, GCP, or Azure for storage & pipelines
- S3, Lambda, Glue, Dataproc, BigQuery, etc.

βœ… Tip 8: Data Quality & Testing
- Implement checks for missing, duplicate, or inconsistent data
- Monitor pipelines for failures

βœ… Tip 9: Real Projects
- Build end-to-end pipeline: API β†’ ETL β†’ Warehouse β†’ Dashboard
- Work with streaming data (Kafka, Spark Streaming)

βœ… Tip 10: Stay Updated & Practice
- Follow blogs, join communities, explore new tools
- Practice with Kaggle datasets and real-world scenarios

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Descriptive Statistics and Exploratory Data Analysis.pdf
1 MB
Covers basic numerical and graphical summaries with practical examples, from University of Washington.
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βœ… 15 Data Engineering Interview Questions for Freshers πŸ› οΈπŸ“Š

These are core questions freshers face in 2025 interviewsβ€”per recent guides from DataCamp and GeeksforGeeks, ETL and pipelines remain staples, with added emphasis on cloud tools like AWS Glue for scalability. Your list nails the basics; practice explaining with real examples to shine!

1) What is Data Engineering?
Answer: Data Engineering involves designing, building, and managing systems and pipelines that collect, store, and process large volumes of data efficiently.

2) What is ETL?
Answer: ETL stands for Extract, Transform, Load β€” a process to extract data from sources, transform it into usable formats, and load it into a data warehouse or database.

3) Difference between ETL and ELT?
Answer: ETL transforms data before loading it; ELT loads raw data first, then transforms it inside the destination system.

4) What are Data Lakes and Data Warehouses?
Answer:
⦁ Data Lake: Stores raw, unstructured or structured data at scale.
⦁ Data Warehouse: Stores processed, structured data optimized for analytics.

5) What is a pipeline in Data Engineering?
Answer: A series of automated steps that move and transform data from source to destination.

6) What tools are commonly used in Data Engineering?
Answer: Apache Spark, Hadoop, Airflow, Kafka, SQL, Python, AWS Glue, Google BigQuery, etc.

7) What is Apache Kafka used for?
Answer: Kafka is a distributed event streaming platform used for real-time data pipelines and streaming apps.

8) What is the role of a Data Engineer?
Answer: To build reliable data pipelines, ensure data quality, optimize storage, and support data analytics teams.

9) What is schema-on-read vs schema-on-write?
Answer:
⦁ Schema-on-write: Data is structured when written (used in data warehouses).
⦁ Schema-on-read: Data is structured only when read (used in data lakes).

10) What are partitions in big data?
Answer: Partitioning splits data into parts based on keys (like date) to improve query performance.

11) How do you ensure data quality?
Answer: Data validation, cleansing, monitoring pipelines, and using checks for duplicates, nulls, or inconsistencies.

12) What is Apache Airflow?
Answer: An open-source workflow scheduler to programmatically author, schedule, and monitor data pipelines.

13) What is the difference between batch processing and stream processing?
Answer:
⦁ Batch: Processing large data chunks at intervals.
⦁ Stream: Processing data continuously in real-time.

14) What is data lineage?
Answer: Tracking the origin, movement, and transformation history of data through the pipeline.

15) How do you optimize data pipelines?
Answer: By parallelizing tasks, minimizing data movement, caching intermediate results, and monitoring resource usage.

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