4.The important or main object in a database is a table which consists or rows and columns. The choosing the ETL tool is very difficult thing. Following are some important examples of tranformation : Question 20 : How do you maintain logs mechanism in ETL? Here are data modelling interview questions for fresher as well as experienced candidates. These are most important ETL Interview questions with answers with examples. Transformation are of two types Active and Passive. Here, we have given a complete list of ETL testing interview questions and answers for freshers and experienced to help the job seekers in the best way. Hope you like this article. How many steps ETL contains? Download PDF. 250+ Etl Testing Interview Questions and Answers, Question1: What is ETL? Below is the top 2020 ETL Interview Questions that are asked frequently in an interview. 12) Explain what is partitioning, hash partitioning and round robin partitioning? 26) Explain these terms Session, Worklet, Mapplet and Workflow ? It consists of facts called as measures categorized by dimensions. If you want to migrate the data using simple way use different ETL tools. To move the data from one company to another company the ETL concepts is been used. Facts are related to dimensions. In case if you have non-OLEBD source for the lookup then you have to use Cache to load data and use it as source. ( 50% asked ETL interview questions with answers ). Top 10 SSIS Advanced Interview Questions And Answers 2018 Pdf. Home » ETL TESTING Questions » 300+ [LATEST] Etl Testing Interview Questions and Answers. 10 Top ETL Interview Questions and Answers to Help Get You Hired January 24, 2020. 300+ SSIS Interview Questions For Experienced. It supports ERP sources such as SAP, people soft etc. To determine whether the candidate for the data warehouse/ETL developer is the right one for the job, it’s important to ask the right questions in the interview. The staging area data is already there and the we can use that data for faster processing of data in transformation process. 7) Explain what is tracing level and what are the types? 1) What... What is Database? Question 11 : What are different types of data model used in ETL process? Load data task adds records to a database table in a warehouse. These products are used for software solutions. Data warehouse is used for reporting and data analysis purpose. ETL - 103 ETL interview questions and 407 answers by expert members with experience in ETL subject. Loading performance : It will improve the performace of tranformation and faster loading of the data. Data warehousing is the process of aggregating data from multiple sources into one common repository. If you want to learn Practical ETL Testing Training then please go through this ETL Testing Training in Chennai. 9) Explain what factless fact schema is and what is Measures? SSIS or SQL Server Integration Services (SSIS) is a component of Microsoft SQL Server, which can be used to accomplish a broad range of data transformation and migration tasks. 3) Mention what are the types of data warehouse applications and what is the difference between data mining and data warehousing? Q3. We need to use ETL process to extract data from source and load it in the target system. Tracing level is the amount of data stored in the log files. Ques.1. 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. What are the steps involved in an ETL process? 2.Determining location to place hierarchy of each dimension of information. Measures that can be added across some dimensions. It is an essential concept in Data Warehousing systems. While, load does the process of writing the data into the target database. Part 1 – ETL Interview Questions (Basic) This first part covers basic Interview Questions and Answers. Free interview details posted anonymously by Target interview candidates. Explain with example. Question 8 : Explain the Extraction,Transformation and loading in single statement. 19) Explain what is the difference between OLAP tools and ETL tools ? | OCA Preparation 5, What is substitution variables in SQL with real life examples? What are conversion functions in SQL? (60% asked ETL Testing Interview Questions) Answer : ETL tools are widely used in data migration projects. Granularity in table represents the level of information stored in the table.In BI granularity is very important concept to check the table data.The granularity is high and low .High granularity data contains the data with high information or you can say it as transaction level data is high granularity data.Low granularity means data has low level information only.Fact table always have low granularity mean we need very low level data in fact table. Invalid data : Make sure that no invalid data is loaded at target. If the organization is managing the data in oracle 10 g previously and now organization wants to go for SQL server cloud database then there is need to migrate the data from Source to Target.To do this kind of migration the ETL tools are very useful. For more info please access vi's website. Hadoop, Data Science, Statistics & others. We can use audit tables in staging area which will make sure that the data processing is done properly in data-warehouses database.It will write the history of table. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. Question 13 : What is mean by data mart? Question 22 : Explain multiple steps to choose ETL tool . It is also known as Fact Granularity. Question 15 : What are cubes? 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. The following is the explaination about the data extraction process pointwise : 1.The initial process is to extract the data from multiple heterogeneous sources from source systems. 1) What is ETL? What is your experience in the field? Explain with example. Cubes are data processing units comprised of fact tables and dimensions from the data warehouse. It is a central component of a multi-dimensional model which contains the measures to be analysed. Each source system as the seperate format of data may be in relational DBMS or any other XML or JSON formats and we require to include non relational systems in extraction process like  Information Management System (IMS) or other data structures such as Virtual Storage Access Method (VSAM) or Indexed Sequential Access Method (ISAM). Question 4 : What are different types of ETL tools? Between Informatica and SAP Powerconnect act as a gateaway. The ETL system is mostly been used in the Datawarehouse where we require transformed data. ETL stands for Extract,Transform and Load which is used for data-warehousing system. Using the Data-warehouse the higher management will take the strategic as well as tactical decisions. 4.Example of Data Transformation : If we require to use first name and last name together in reporting or data-warehousing database we require to use the data transformation technique to merge First name + Last name. The ETL is used in data warehousing concepts. NumPy is an open source library available in Python that aids in mathematical,... Verify whether the data is transforming correctly according to business requirements, Verify that the projected data is loaded into the data warehouse without any truncation and data loss, Make sure that ETL application reports invalid data and replaces with default values, Make sure that data loads at expected time frame to improve scalability and performance, Getting a related value from a table using a column value, Verify whether records already exist in the table, By informatica data is distributed evenly among all partitions, In each partition where the number of rows to process are approximately same this partioning is applicable, For the purpose of partitioning keys to group data among partitions Informatica server applies a hash function, It is used when ensuring the processes groups of rows with the same partitioning key in the same partition need to be ensured, Use full database name for updating if MSSQL is used, Dynamic cache is used when you have to update master table and slowly changing dimensions (SCD) type 1, It can be connected to another transformations and returns a value, Another transformation cannot be connected, Static or dynamic cache can be used for connected Lookup, Connected lookup supports user defined default values, Unconnected look up does not support user defined default values, In Connected Lookup multiple column can be return from the same row or insert into dynamic lookup cache, Unconnected lookup designate one return port and returns one column from each row, With the power connect option you extract SAP data using informatica, Install and configure the PowerConnect tool, Import the source into the Source Analyzer. As it currently stands, this question is not a good fit for our Q&A format. You are playing with the organization data while doing the ETL process.So Choose vendor who is very well known in the industry and whose support is really great. The approach by which physical data models are created is called as physical data modeling. Following 2 points are important in defining granularity : 1.Determining the dimensions that are to be included. ETL interview questions? Question 9 : What are different types of fact tables? Question 1 : What is mean by ETL? 2.Physical data model includes all required tables, columns, relationship, database properties for the physical implementation of databases. Unconnected lookup? What is a materialized view log? There are lot of opportunities from many reputed companies in the world. 3.The important function of data transformation is cleansing of the data and add the data in target according to the business requirements. Question 19 : Explain multiple examples of transformation in ETL process. Demonstrating your technical knowledge of ETL (Extract, Transform and Load) processes is important to make a strong impression during an interview for a position in technology. 14) Using SSIS ( SQL Server Integration Service) what are the possible ways to update table? Grain fact can be defined as the level at which the fact information is stored. Rather than directly from data source objects, dimensions and cubes are created from data source views. When such a table or file exists, the next step would be to prepare notifications. The business intelligence 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. To improve performance, transactions are sub divided, this is called as Partitioning. ETL testing interview questions and answers ETL testing is a popular trend today with plenty of job opportunities and attractive salary options. While OLAP is meant for reporting purpose in OLAP data available in multi-directional model. - … To update table using SSIS the possible ways are: 15) In case you have non-OLEDB (Object Linking and Embedding Database) source for the lookup what would you do? ITEM KEY will be present in Fact table. 3. Schema objects includes tables, views, sequence synonyms, indexes, clusters, functions packages and database links. - It is used when lookup function is used instead of an expression transformation while mapping. 4.There are following different things used for creating logical data model: Entities, Attributes, Super Types, Sub Types, Primary Key, Alternate Key, Inversion Key Entry, Rule, Relationship, Definition, business rule, etc. So, these are the few questions which were asked me during the first round. ( 100% asked ETL interview questions with answers ). Discuss each question in detail for better understanding and in-depth knowledge of ETL It covers basic architecture questions, utilities related – Fastload, Multiload, BTEQ questions, SQL questions, Stored Procedure related questions below. As an example let us consider the example of customer management department and we require to fetch data from oracle as well as mysql databases. Now a days lot of companies are merging in to different MNCs. What is an ETL process? This way the load can be checked for invalid runs. ETL is nothing but Extract,Transform and Loading of the data from multiple heterogeneous data sources to a single or multiple sources. The Staging area is optional intermediate data processing area where we can extract the data from multiple heterogeneous sources. It consists of facts called as measures categorized by dimensions. Talend is one of the most powerful ETL tools that contain different products like data quality, application integration, data management, data integration, data preparation, and big data. Your email address will not be published. How many steps are there in an ETL process? What are the types of facts? | OCA-4, What is where clause in SQL with real life examples? OLAP stands for Online Analytics Processing, and OLAP cube stores large data in muti-dimensional form for reporting purposes. 17) Explain what are the differences between Unconnected and Connected lookup? The most common ways to prepare for logging are to use flat files or a logging table. Following are frequently asked SSIS Interview questions for freshers as well as experienced Database managers. If you're looking for ETL Testing Interview Questions & Answers for Experienced or Freshers, you are at right place. Data warehouse helps consolidated historical data analysis. (60% asked ETL Testing Interview Questions). 6) Explain what are Cubes and OLAP Cubes? 2.What is Full load & Incremental or Refresh load? There are three basics steps in … 1) What is SSIS? Explain the architecture of the ETL and DWH? A data warehouse is a blend of technologies and components which allows the... What is Data Reconciliation? The ETL tools are used to extract the data from different data sources, transform the data, and load it into a data warehouse system. ETL Testing Interview Questions . Extract does the process of reading data from a database. To make this simple the ETL tools are very useful in which the coding is simple as compare to PL SQL or T-SQL code.So ETL process i very useful in Data migration projects. In this article i would like to give some basic ETL interview questions with answers in detail. So you need to check the performance factors. ETL stands for extraction, transformation and loading. Required fields are marked *. Take data from an external source and move it to the warehouse pre-processor database. Data Transformation checks : We require to check the data is transformed as per the requirements or not. ETL is nothing but Extraction,Transformation and Loading of the data. Viewed 2k times -1. Question 10 : What are different usages of ETL process? Prepare the ETL interview questions listed below and get ready to crack your job interview: Q1. In Star schema there is Fact table as a center and all dimension tables surrounded with that  fact table.It is called as Star schema because diagram resembles a star with points radiating from center.Star schema is used in simple data mart or data warehouse.Star schema is designed in such way that it will optimize the querying on large data sets.In Star schema multiple dimension tables joined with only one fact table in de-normalized form. I am looking for a big picture and how it fits in the overall .NET/SQL Server architecture. The data coming from ETL system is used to create the BI reports to check for organizational growth. Top 25 ETL Testing Interview Questions & Answers Following are frequently asked questions in interviews for freshers as well experienced ETL tester and developer. Following are frequently asked questions in interviews for freshers as well experienced ETL tester and developer. Q1. The types of data warehouse applications are, Data mining can be define as the process of extracting hidden predictive information from large databases and interpret the data while data warehousing may make use of a data mine for analytical processing of the data in a faster way. ( 60% asked ETL interview questions with answers ). ELT stands for Extract the data as first step, Load the data and then do transformation. Click below to consent to the use of the cookie technology provided by vi (video intelligence AG) to personalize content and advertising. Schema objects are the logical structure that directly refer to the databases data. Data warehouse database contains transactional as well as analytical data. Ans. Data warehouse helps business user to see the current trends to run the business. ETL Testing Interview Questions : In my previous articles i have explained about ETL definition and its concept in brief. Use of data-mart in ETL : We require to transform and load data for single functional area from multiple sources at that time ETL is been used. Auditing of data : The staging data is useful data for auditing purpose. In data warehousing architecture, ETL is an important component, … Data-warehouse database is used to store the operational data as well as historical data. Following are multiple usages of staging the data from multiple sources : Faster Data Processing : The staging area is used to process data faster than directly processing the data. Talend Interview Questions. As The ETL definition suggests that ETL is nothing but Extract,Transform and loading of the data;This process needs to be used in data warehousing widely. What is use of data-mart in ETL? Data staging includes following steps, For the various business process to identify the common dimensions, BUS schema is used. 173 Target ETL interview questions and 154 interview reviews. ETL tool should be communicate with any source of data no matter where it comes from.This is very critical. In DataStage interview questions, you will get all the information you need to clear your DataStage interviews with care. Explain with example. BI tools are used to generate interactive and ad-hoc reports for end-users, data visualization for monthly, quarterly, and annual board meetings. Question 23 :Explain Star Schema in ETL process with Example. 300+ [LATEST] Etl Testing Interview Questions and Answers. According to research ETL Testing has a market share of about 15%. So we are using the ETL to create Near real time reports. Data purging is a process of deleting data from data warehouse. There are following examples where we are using the ETL : Data warehouse is a database which is separate from operational database which stores historical information also. Before ETL tool user needs to write a long code for data transformation to data loading, ETL makes the life simple and one tool will manage all the scenarios of transformation and loading of the data. Transform data task allows point-to-point generating, modifying and transforming data. Explain importance of staging area. | OCA article 3, How to retrieve data in SQL? 3.The logical data model is the actual implementation and extension of a conceptual data model. … question 21: How ETL is used for reporting and data?! I appeared for the various tools used in data migration projects a representation of database... The information you need to use flat files or a logging table event such SAP... 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Research ETL Testing interview questions for fresher as well, transformation and job control.... Database in logical way by staging area higher management will take the strategic as well as tactical decisions happy..