In other words, a data warehouse contains a wide variety of data that supports the decision-making process in an organization. It has no specification to convert local into global repository, Source data extraction and data transformation ( restructuring ), Data transformation (data cleansing, value transformation ), Mapplet : It arranges or creates sets of transformation, Worklet: It represents a specific set of tasks given, Workflow: It's a set of instructions that tell the server how to execute tasks, Session: It is a set of parameters that tells the server how to move data from sources to target. A data warehouse is often built to enable Data Analytics. It can view the number of occurring events. Data analytics (DA) is the science of examining raw data with the purpose of drawing conclusions about that information. A list of frequently asked ETL Testing Interview Questions and Answers are given below. The numeric data based on columns in a fact table is known as Measures, A transformation is a repository object which generates, modifies or passes data. Click below to consent to the use of the cookie technology provided by vi (video intelligence AG) to personalize content and advertising. The 3 Biggest Issues with Data Warehouse Testing. List the types of Data warehouse architectures. ITEM KEY will be present in Fact table. If Company head wants transactional report of all Employees In – Out time. So, the basic testing questions will also remain same. 14) Using SSIS ( SQL Server Integration Service) what are the possible ways to update table? Data Warehousing - 3842 Data Warehousing interview questions and 10294 answers by expert members with experience in Data Warehousing subject. Schema objects includes tables, views, sequence synonyms, indexes, clusters, functions packages and database links. Part 1 – Data warehouse Interview Questions … Fact table is central table found in star schema or snowflakes schema which is surrounded by dimension tables.Fact table contains numeric values that are known as measurements.Fact table has two types of columns: The measures in a fact table are of three types : Measures that can be added across any dimension, Measures that can not be added across any dimension. Once all the data is gathered from all its raw data via multiple sources, the data is processed using ETL into practical information which the business users can then apply various business rules to determine the … Partioning enables Informatica Server for creating of multiple connection to various sources. The main objective of ETL testing is to identify and mitigate data defects and general errors that occur prior to processing of data for analytical reporting. 20.What is mean by additive,semi-additive and non-additive measures? In Diagram i shown the snowflake schema where sales table is a fact table and all are dimensions.Store table is further normalized in to different tables name city,state and region. The term Data Warehouse provides the user with the data and tool to answer the questions which are important to run the business or part of business.In short,the Data warehouse is used for reporting the specified data of any business which is very important and using which  the higher management of the business will take the decisions for growth of business.Now a days Business Intelligence is demanding technology to analyse the business and its history.In this article i will try to explain 20 Most important Data warehouse Interview Questions.I have explained about SQL interview questions in other articles.These questions are helpful to BI developers as well as Data warehouse people to crack the Data warehouse interviews: 1.What is OLAP(Online Analytical Processing)? It comes with a conformed dimensions along with a standardized definition of information. SUM(), AVG() etc.). Sum is meaningless on rate; however, average function might be useful. To improve performance, transactions are sub divided, this is called as Partitioning. It is an integral part of any effective business intelligence initiative. On either side of this middle system are the end users and the back-end data … The fact table contains the foreign keys,time dimensions,product dimension,customer dimension,measurement values.Following are some examples of common facts : No of unit sold,Margin,Sales revenue and the dimension tables are customer,time and product e.t.c. The advantage of using the DataReader Destination Adapter is that it populates an ADO recordset (consist of records and columns) in memory and exposes the data from the DataFlow task by implementing the DataReader interface, so that other application can consume the data. Data Warehousing Interview Questions and Answers for Experienced. Data warehousing is the process of aggregating data from multiple sources into one common repository. These support transaction processing of high-volume. 10.What is mean by Fact Tables?Explain with example. In the image i have explained which are fact and which are dimension tables. If you have attended DWBI interviews in the recent past, we encourage you to paste additional questions in the comments tab. Let’s say account balance. 11) Explain the use of Lookup Transformation? According to research ETL Testing … A data warehouse is a huge store of data accumulated from a broad range of sources within an organization and used to guide business decisions. What Is A Three Tier Data Warehouse? (100 % Asked Data warehouse Interview Questions ). Postgresql Interview Questions | Postgresql Intereview Questions with Answers, PL SQL Developer Roles and Responsibilities | Resume of PL SQL Developer, What are features of single row functions? If table contains the data of year 2016 and 2017 ,User wants a actual count of records in the table monthly,Quarterly and yearly.Then We need to make aggregate table which contains count of records  monthly,For Quarterly we need to create other table and push the quarterly count in that table.And we need to use that tables in the reports so that report performance will improve drastically. It provides multi-dimensional analysis. These Objective type Data Warehouse Questions are very important for campus placement test and job interviews. Data and information are extracted from heterogeneous sources as they are generated....This makes it much easier and more efficient to run queries over data that originally came from different sources. Online Analytical Processing, a category of software tools which provide analysis of data... What is Data? Example, 5% profit margin, revenue to asset ratio etc. In this article, we will provide the 50 most common questions, including some with sample answers, to help you prepare for your data warehousing interview. | OCA Preparation -1. The next step is to generate the ABAP code for the mapping then only informatica can pull data from SAP, To connect and import sources from external systems Power Connect is used. 1) Data transformation Testing: Verify that data is transformed correctly according to various business requirements and rules.. 2) Source to Target count Testing: Make sure that the count of records loaded in the target is matching with the expected count.. 3) Source to Target Data Testing: Make sure that all projected data is loaded into the data warehouse … Today we often call this whole process of reporting data from data warehouses as “Data Analytics”. Careful preparation will enable you to make the best impression on the interviewer. (100 % asked BI Interview Question). If you're looking for ETL Testing Interview Questions & Answers for Experienced or Freshers, you are at right place. In this Software Testing interview questions article, I have collected the most frequently asked questions by interviewers. OBIEE BMM(Business model) Layer always follows star schema. Data Warehouse is a repository of integrated information, available for queries and analysis. Data warehousing is a system which is used for reporting purpose as well as data analysis purpose where data is coming from multiple heterogeneous sources whether it is  oracle, sql server, postgres,simple excel sheet.Data warehousing is specially used for reporting historical data.Data warehousing is core component of Business Intelligence.In Data warehouse there is one central mechanism called as repository using which one can fetch the historical reports.In Data warehouse user can store current data as well as historical data on single place called as repository.Data warehouse provides generalized data and consolidated data in multidimensional view.Data warehouse provides Online Analytical tools to analyse the data and reporting purpose. It supports ERP sources such as SAP, people soft etc. Operational or Transactional database have insert,update privileges as the data processing and updation needed. Data Warehousing Interview Questions and Answers will guide now that Data warehouse is a repository of an organizations electronically stored data. e.g. Data Mart is a simplest set of Data warehouse which is used to focus on single functional area of the business.We can say Data Mart is a subset of Data warehouse which is oriented to specific line of business or specific functional area of business such as marketing,finance,sales e.t.c. For a long time in the past and also even today, Data warehouses are built to facilitate reporting on different key business processes of an organization, known as KPI. Any numeric aggregation function like sum ( ), AVG ( ).... Log files which stores historical information also of dimensions table and added measures for,. Keys from dimension tables that qualifies the data warehouse database contains transactional as well experienced ETL and. Using historical or current data ) is the process of aggregating data from a database verified... 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