CompTIA Data+ (DA0-002)Data MiningMedium
A data engineer is designing an ETL process for a new enterprise data warehouse. The source system contains customer data from various legacy applications, each with slightly different data formats and schemas. The engineer needs to ensure that customer records from all sources are merged into a single, consistent format before being loaded into the data warehouse. Which phase of the ETL process is primarily responsible for unifying these disparate data structures and preparing them for the target system?
- ATransformation
- BValidation
- CLoading
- DExtraction
Show answer & explanationAnswer & explanation
Correct answer: A. Transformation
The Transformation phase of ETL is where data from various sources is cleaned, standardized, aggregated, and converted into a format suitable for the target data warehouse. This includes handling schema differences and ensuring data consistency.
Why the other options are wrong
- B. Validation is a quality assurance step that can occur at various points, but it's not the primary phase for structural unification.
- C. Loading involves writing the transformed data into the target system, not the actual modification of data format.
- D. Extraction is focused on retrieving data from source systems, not on changing its format or structure.
ETL Transformation
The second phase of the ETL (Extract, Transform, Load) process, where raw data is cleaned, standardized, aggregated, and converted into a format suitable for the target data store.
- Handles data cleansing, standardization, and deduplication.
- Performs data type conversions and schema mapping.
- Aggregates and calculates new metrics from raw data.
Memory trick: ETL: Extract, Transform, Load – the data journey's road.