Post by account_disabled on Mar 11, 2024 23:33:13 GMT -5
Below are some questions for intermediate level ETL developers. Use them for recruiting for mid-level positions where candidates already have hands-on experience using ETL. Intermediate ETL Developer Interview Questions 9. How is data analyzed in ETL? Example answer : Once the data has been successfully transported to the data warehouse, analysts typically use third-party business intelligence (BI) applications, such as Tableau, to convert the raw data into graphs and charts, based on which decisions can be made. business. Some of the newer ETL tools are equipped with their own data analysis mechanisms. 10. What are some of the most common types of ETL tests? Example answer : There are several ETL testing methods, each serving a specific purpose at different points in the ETL process. Some of the most common types of ETL tests are: Production validation: Data from the target system is compared to that from the sources for validity. Source to destination count tests: The number of records loaded into the data warehouse is checked to be consistent with the expected record count.
Performance Testing: The upload process is tested to ensure that it occurs within the expected time frames. Data transformation testing: Data in the target system is checked to verify that it has been successfully Bahamas Mobile Number List transformed according to business requirements. 11. What are snapshots in ETL? Example answer : Snapshots are read-only copies of the master table data. Before a change is made to the data store, a snapshot is taken and stored locally for reference. This is to preserve the records as they were before the change was made. Each snapshot has three components: The time it was taken. A key to identify the snapshot. The data related to the key. 12. What is data profiling in ETL? Example answer : Data profiling is the process of reviewing source data to identify its structure, quality, and interrelationships. It is an important precursor to the analysis phase as it ensures that the appropriate source data is loaded into the data warehouse and transformed according to business requirements. 13. What are the most common ETL errors? Example answer : ETL testing can reveal a wide variety of problems.
Some of them are: Data loss between the source and destination system. Lack of consistency between data sets. Long query processing. System crashes due to data warehouse scale. Aesthetic errors related to font, color or alignment. 14. What does ETL three-tier architecture mean? Example answer : Most data warehouses comprise three separate areas. These are: The staging area , where data is extracted from various sources and processed. The data integration area , where data is transformed from the staging area (sometimes called OLAP server). The access area , where the transformed data is retrieved by users for analysis. 15. Why is the staging area important in the ETL process? Example answer : The staging area is the landing zone for data extracted from sources and sits between the source and target in the ETL process. Here data is cleaned and modified before being transferred to the data warehouse. This is a more efficient alternative to transforming data in the target system itself. 16. What is the difference between an initial load and an incremental load in the ETL process? Example answer.
Performance Testing: The upload process is tested to ensure that it occurs within the expected time frames. Data transformation testing: Data in the target system is checked to verify that it has been successfully Bahamas Mobile Number List transformed according to business requirements. 11. What are snapshots in ETL? Example answer : Snapshots are read-only copies of the master table data. Before a change is made to the data store, a snapshot is taken and stored locally for reference. This is to preserve the records as they were before the change was made. Each snapshot has three components: The time it was taken. A key to identify the snapshot. The data related to the key. 12. What is data profiling in ETL? Example answer : Data profiling is the process of reviewing source data to identify its structure, quality, and interrelationships. It is an important precursor to the analysis phase as it ensures that the appropriate source data is loaded into the data warehouse and transformed according to business requirements. 13. What are the most common ETL errors? Example answer : ETL testing can reveal a wide variety of problems.
Some of them are: Data loss between the source and destination system. Lack of consistency between data sets. Long query processing. System crashes due to data warehouse scale. Aesthetic errors related to font, color or alignment. 14. What does ETL three-tier architecture mean? Example answer : Most data warehouses comprise three separate areas. These are: The staging area , where data is extracted from various sources and processed. The data integration area , where data is transformed from the staging area (sometimes called OLAP server). The access area , where the transformed data is retrieved by users for analysis. 15. Why is the staging area important in the ETL process? Example answer : The staging area is the landing zone for data extracted from sources and sits between the source and target in the ETL process. Here data is cleaned and modified before being transferred to the data warehouse. This is a more efficient alternative to transforming data in the target system itself. 16. What is the difference between an initial load and an incremental load in the ETL process? Example answer.