Cyber Security Infotech Ethical Hacking Trainer Interview Questions and Answers

Common validation techniques in ETL testing include data completeness, data accuracy, data transformation, and data quality checks.

• Data completeness validation ensures that all expected data is loaded into the target system.

• Data accuracy validation involves verifying that the data is correctly transformed and loaded without any errors.

• Data transformation validation checks if the data is transformed according to the bus...read more

Use SQL query with ORDER BY and LIMIT to fetch 5th highest salary.

• Use ORDER BY clause to sort salaries in descending order

• Use LIMIT 1 OFFSET 4 to fetch the 5th highest salary

Filter stage is used in ETL processes to selectively pass or reject data based on specified criteria.

• Filter stage helps in removing unwanted data from the input dataset.

• It can be used to apply conditions like filtering out duplicate records, selecting specific columns, or excluding certain values.

• For example, a filter stage can be used to only pass records where the sales amount is greater than $1000.

Transform stage is used in ETL process to apply business rules, clean and enrich data before loading into target database.

• Transform stage is used to apply business rules to the data.

• It is used to clean and standardize data before loading into the target database.

• Transform stage can also be used to enrich data by combining multiple sources or adding calculated fields.

• Examples include converting data types, removing dupl

Sort stage is used in ETL processes to sort data based on specified criteria before loading it into the target system.

• Sort stage helps in arranging data in a specific order for better analysis and reporting

• It can be used to remove duplicates from data before loading

• Sorting can be done based on multiple columns or expressions

• Example: Sorting customer data based on their purchase amount before loading into a data warehou

To create a parallel job, use parallel processing techniques to divide tasks into smaller subtasks that can be executed simultaneously.

• Identify tasks that can be executed independently and in parallel

• Use parallel processing techniques such as multi-threading or distributed computing

• Implement parallel job using ETL tools like Informatica or Talend

• Monitor and optimize parallel job performance to ensure efficient executio

SCD stands for Slowly Changing Dimension, a technique used in data warehousing to track changes in dimension attributes over time.

• SCD is used to maintain historical data in a data warehouse

• There are different types of SCDs - Type 1, Type 2, and Type 3

• Type 1 SCD overwrites old data with new data

• Type 2 SCD creates a new record for each change and maintains history

• Type 3 SCD keeps a limited history by adding columns to tr

The SQL query to find records that never contain flag 0 in the critical column.

• Use the NOT EXISTS operator to check if there are no records with flag 0 for each distinct value in the critical column.

• Write a subquery to select distinct values from the critical column.

• Join the main table with the subquery using the critical column.

• Filter the result by checking if there are no records with flag 0 for each distinct value i

To validate between two integers, compare each corresponding digit and check if they are equal.

• Convert both integers to strings

• Pad the source integer with leading zeros to match the length of the target integer

• Compare each digit of the source and target integers

• If any digit is not equal, the validation fails

The question is asking to rearrange the numbers so that 100 is at the first row and the rest are below it.

• Create an array of strings to store the numbers

• Assign the value '100' to the first element of the array

• Use a loop to assign the numbers 1 to 99 to the remaining elements of the array

Set and join are operations used in database management systems.

• Set is used to perform mathematical set operations like union, intersection, and difference on two or more sets.

• Join is used to combine rows from two or more tables based on a related column between them.

• Set operations do not require a common column, while join operations do.

• Set operations return a result set with unique values, while join operations retur...read more

The output for inner join will be the rows where both col1 and col2 have non-null values.

• Inner join returns only the matching rows from both tables.

• In this case, the output will be the rows with non-null values in both col1 and col2.

• Rows with null or blank values in either col1 or col2 will be excluded from the output.