Mphasis Datastage Developer Interview Questions and Answers

Q1. Difference between join and lookup
Ans. 
Join is used to combine rows from two or more tables based on a related column, while lookup is used to retrieve data from a reference table based on a matching key.
• Join combines rows from multiple tables based on a related column

• Lookup retrieves data from a reference table based on a matching key

• Join can result in duplicate rows if there are multiple matches, while lookup returns only the first matching row

• Join is use...read more
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Q2. Diffrence between fact table and dimension table
Ans. 
Fact table contains quantitative data and measures, while dimension table contains descriptive attributes.
• Fact table contains numerical data that can be aggregated (e.g. sales revenue, quantity sold)

• Dimension table contains descriptive attributes for analysis (e.g. product name, customer details)

• Fact table is typically normalized, while dimension table is denormalized for faster queries

• Fact table is usually larger in s
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Q3. Sed command to display last before line
Ans. 
Use sed command to display the line before a specific pattern
• Use 'sed -n '/pattern/{g;1!p;};h' file.txt' to display the line before the pattern

• Replace 'pattern' with the specific pattern you are looking for

• This command will display the line before the pattern in the file
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Q1. Discuss 4 case study related to supply chain management.
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Round duration - 140 minutes
Round difficulty - Medium

Test timing was at 2:00 pm , it was conducted in a college and the environment was good for the test. Camera was a primary part of test, so no suspicious activity.

Q1. 
Sum of Two Numbers Represented as Arrays
Given two numbers in the form of two arrays where each element of the array represents a digit, calculate the sum of these two numbers and return this sum as an ar...read more
Ans. 
Given two numbers represented as arrays, calculate their sum and return the result as an array.
• Iterate through the arrays from right to left, adding digits and carrying over if necessary

• Handle cases where one array is longer than the other by considering the remaining digits

• Ensure the final sum array does not have any leading zeros
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Round duration - 20 minutes
Round difficulty - Easy

The round was conducted at around 12 p.m. I was called at the college location and then it was conducted. The interviewer was quite polite and frank.

Round duration - 8 minutes
Round difficulty - Easy

This round was conducted right after finishing and clearing the technical round at the same place and on the same day.