The popular etl testing questions for interviews need now

The below 10 etl questions identified in my analysis and useful for ETL developers and testers.

ETL 10 interview Questions
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  1. What is source identification?
    1. The database/files where they located for etl processing is called identifying source
  2. what is the method of extractions?
    1. For each requirement weather the method is manual or Tool based. If it is tool based, need to identify which tool to be used
  3. What is frequency of extraction?
    1. The frequency can be hourly, weekly, daily quarterly , monthly….
  4. What is job dependency?
    1. Need to identify the dependent jobs for a given job to do extraction process
  5. What happens when there are different sources are present?
    1. You need to choose relevant data source
  6. What is immediate data extraction?
    1. This is called real time data extraction also called on the fly extraction
  7. What are the data transformation techniques?
    1. Either you select only selected columns from the source
    2. By method of splitting and joining
    3. Selecting data by summarization
  8. What is full refresh?
    1. The full refresh is similar to the initial load
  9. What is update in data loading?
    1. Something like reload of specified intervals. also, incremental changes
  10. What are Type-1, TYpe-2 and Type-3 changes or loading?
    1. Type-1 is overwrite old value
    2. Type-2 is creating a new dimension record
    3. Type-3 is push down changed value to ‘old’ attribute
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Author: Srini

Experienced software developer. Skills in Development, Coding, Testing and Debugging. Good Data analytic skills (Data Warehousing and BI). Also skills in Mainframe.