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