QlikView Interview Questions

 Q.Explain Qlikview architecture? Ans: QlikView deployments have three main infrastructure components: 1.QlikView Developer :  Is a Windows-based desktop tool that is used by designers and developers to create

  1. a) a data extract and transformation model and
  2. b) to create the graphical user interface (or presentation layer).

2.QlikView Server (QVS) : Handles the communication between clients and the QlikView applications. It loads QlikView applications into memory and calculates and presents user selections in real time. 3.QlikView Publisher: Loads data from different data sources (oledb/odbc, xml, xls), reduces the QlikView application and distributes to a QVS. Because QlikView Server and Publisher have different roles and handle CPU and memory differently it’s considered a best practice to separate these two components on different servers. Q.Set analysis in qlikview ? Ans:  Used for set of groups .. mostly used in arrgeted function like sum (year) used    sales of current year VS last year. Q.What is Synthetic key and how to avoid it in QlikView? Ans:  It is undesirable to have multiple common keys across multiple tables in a QlikView data structure. This may cause QlikView to use complex keys (a.k.a. synthetic keys) to generate the connections in the data structure. Synthetic keys are generally resource heavy and may slow down calculations and, in extreme cases, overload anapplication. They also make a document harder to understand and maintain. Thereare some cases where synthetic keys cannot be avoided (e.g. Interval Match tables),but, in general, synthetic keys should always be eliminated, if possible.

  1. comment the fileds in load script
  2. rename the fileds in load script
  3. rename the fileds using UNQUALIFY operator;

Q.Difference between keep and joins ? Ans : Left Keep and Left join gives the same output. The only difference is that Left Keep keeps the Table separate in Data Model, whereas Left join merges the Tables that are joined. Q.Difference between Straight table and pivot table ? Ans:  Pivot Table – 1) A pivot table is better at grouping: you can easily see which group a specific row belongs to, and a group can have a subtotal. 2) You can also display a pivot table like a cross table (one or several horizontal dimensions). 3) But when you sort a pivot table, you have to sort it first according to the first dimension, then according to the next, etc. You cannot sort it any way you want. Straight Table- A straight table is better at sorting than a pivot table: you can sort it according to any column. But it is not so good at grouping. Subtotals are not possible, for instance. Q.Which graph will you used for two years difference sale ? Ans:  BAR Graph Q.What is Incremental Load in qlikview? Ans:  As BI apps are expected to deal with larger and larger amounts of data the amount of time that it takes to retrieve that data becomes a serious issue.  This could be due to shear volume of data or the need for frequent refreshes. Either way, you do not want to be pulling all of the data all of the time. What you want to be able to do is just pull the data that has changed, append to that the data that you stored away previously and then get back to the business of analyzing.  This will reduce load on the source database, the network infrastructure and your QlikView server. Q.Whta is Inline memory in QlikView ? Ans:  Create table or add field to table . Q.what is Set and let in QlikView and difference between it? Ans:    SET or a LET statement is often usedTo define the variable. The SET statement is used when you want a variableto hold the string or numeric value that is to the right of the Equal (=) sign. The LET statement is used when you need to evaluate what is to the right of the Equal sign e.g set myVar=5*2   the result is “5*2″ Let myVar=5*2   the result is “10″ Q.Explain QlikView Resident Load? Ans:  Create a new logical table in QlikView, based on a previously loaded (resident) table. Q.What is Apply Map (Mapping Tables)? Ans:  Sometimes you need to add an extra field to a table to use a combination of fields from different tables, or you want to add a field to clean up the data structure. Qlik- View has an effective way to add single fields to a table called mapping tables.  syntax — mapping ( load statement | select statement ) applymap( ‘mapname’, expr, ) Q.What is Dimensions ( What is difference between Expression and Dimension)? Ans:  Each data warehouse consists of dimensions and measures. Dimensions allow data analysis from various perspectives. For example, time dimension could show you the breakdown of sales by year, quarter, month, day and hour. Product dimension could help you see which products bring in the most revenue. Supplier dimension could help you choose those business partners who always deliver their goods on time. Customer dimension could help you pick the strategic set of consumers to whom you’d like to extend your very special offers. Q.Explain about Normalized Data? Ans:  Well Structured Form of Data, which doesnt have any repetition or redundancy of data. Its a kind of Relational data. Its mainly used in OLTP kind of stuffs Denormalized Data – Its a whole bunch of data without any relationship among themselves, with redundancy of data. Its mainly used in OLAP kind of stuffs. Q.What Is Star Sechma ? Ans:  A star schema is the simplest form of dimensional model, in which data is organized into facts and dimensions.  A fact is an event that is counted or measured, such as a sale or login.  A dimension contains reference information about the fact, such as date, product, or customer. A star schema is diagramed by surrounding each fact table with its associated dimensions table. The output diagram resembles a star. Star Schema Definition : A means of aggregating data based on a set of known dimensions. It stores data multidimensionality in a two dimensional Relational Database Management System (RDBMS), such as Oracle. Q.What is Snowflaking Schema ? Ans:  Snowflake Schema: An extension of the star schema by means of applying additional dimensions to the Dimensions of a star schema in a relational environment. Snowflaking is a form of dimensional modeling; dimensions are stored in multiple relational dimension tables.  A snowflake schema is a variation of the star schema. Snowflaking is used to improve the performance of specific queries.  The schema is diagramed with each fact surrounded by its associated dimensions as in a star schema, and those dimensions are further related to other dimensions, branching out into a snowflake pattern. Q.What is Central Link Table? Ans:  In the event of multiple fact tables QlikView In-Memory Technology allows us to create a central link table that only contains the existing data combinations. Instead of Joining the tables the event dimensions can be merged (CONCATENATED) in to one central Link table. This link table can then be linked back to the event measures one side and the dimension tables on the other. Q.What is binary load ? Ans:   Binary load is loading data from another QV file.  For example, you have application A.qvw.  You can create another application B.qvw with script binary A.qvw. binary file  where: file ::= filename Examples: Binary customer.qvw; Binary c:\qv\customer.qvw; The path is the path to the file, either absolute, or relative to the .qvw file containing this script line. Q.What is Container ? Ans:  A container object can be used to hold multiple charts.  You can use a container object to put multiple charts in the same box. All charts will appear in the same window but only one chart will appear active at a given time. You can click the chart title to switch or toggle between charts. A word of advice: Use containers with caution. They form linked objects and might affect the properties of all linked objects. Q.What is a synthetic key? Ans:  It is a field that contains all possible combinations of common fields among tables. Q.What kind of chart we use in Qlikview? Ans: We generally uses bar chart, line chart, combo chart, scatter chart, grid chart, etc. Q.Explain Set analysis in qlikview ?? Ans: It is used for set of groups. Mostly used in arrgeted function like sum (year)etc. Q.Define Trellis chart? Ans: In Trellis chart we can create array of chart based on first dimension. Bitmap chart are also made of trellis display. Q.Explain Mini Chart?.What do you mean by sub reports and how we can create them? Ans: With the help of Mini Chart we can set type of modes instead of values in table mode. We can also change the colors. Q.What is Pivot Table? Ans: Pivot Table: A pivot table is better at the time of grouping. We can also show pivot table like a cross table which is a beneficial feature. But there is one disadvantage of it which is if we have to sort a pivot table than we have to sort it first according to the first dimension then to the next. Q.Which graph we will use for two years difference sale ? Ans: BAR Graph we will use. Q.What is Straight Table? Ans: A straight table is much better at the time of sorting as compared to the pivot table as we can sort it according to any column as per our choice. But it is not good for grouping purpose. Q.How many dimensions we can use in Bar chart? Ans: We can use only two dimension Q.Which Qlikview object has only expression and no dimension? Ans: Gauge chart and list box have only expression and no dimension. Q.How we can use Macros in our application? Ans: We can use macros for various purposes like for reloading the application and to create a object. Q.What do you understand by layers in Qlikview? Ans: The layer are basically set on the sheet object properties layout where bottom, top, normal respective to the number -1,0 and 1. Q.What is Dimensions? Ans: Dimensions allow data examination from various perspectives. Q.Explain about Normalized Data? Ans: Well Structured Form of Data, which doesnt have any repetition or redundancy of data. Its a kind of Relational data. Its mainly used in OLTP kind of stuffs Denormalized Data – Its a whole bunch of data without any relationship among themselves, with redundancy of data. Its mainly used in OLAP kind of stuffs. Q.What Is Star Sechma ? Ans: The simplest form of dimensional model, in which data is prearranged into facts and dimensions is known as Star schema. Q.What is Snowflaking Schema ? Ans: A snowflake schema is a difference of the star schema. Snowflaking is used to improve the presentation of particular queries. Q.Explain interval match? Ans: The internal match is prefixes with the load statement which is used for connecting different numeric values to one or more numeric interval. Q.Explain internal match function()? Ans: Internal match fuction is used to generate data bucket of different sizes. Q.What is Container ? Ans: A container object is used to keep multiple charts. We can use a container object to keep many charts in the same box. Q.What do you understand by extended interval match function()? Ans: Extended interval match function() is used for slowly changing the dimensions. Q.what are the new features in QV 11? Ans: Container Object;Granular Chart Dimension Control; Actions like, clear filed; meta data,etc are the new features in QV 11. Q.Explain joins and its types? Ans: Join is used to convert the given data and whenever we are using joins for converting data its is known ad Data Merging. It has many types:

  1. Left join
  2. Right join
  3. Inner join, etc

Q.What is Left Join? Ans: Left join specifies that the join between the two tables should be left join, it uses before the word join. The resulting table only contain the combination among two tables with the full data set from the first table. Q.Define right join? Ans: Right join specifies that the join between the two tables should be right join, it uses before the word join. The resulting table only contain the combination among two tables with the full data set from the second table. Q.Explain Inner Join? Ans: Inner join specifies that the join between the two tables should be inner join. The resulting table should contain the full data set from both the sides. Q.What are modifiers? Ans: Modifiesr deals with the Fields name. For example: sum({$}Sales) Returns the sales for current selection, but with the selection in “Region” is removed. Q.Explain Identifiers Syntax?

  1. 0- Represents the empty set
  2. 1- Represents the full sets of records
  3. $-Represents the record of current selection
  4. $1-Represents the previous selection
  5. $_1-Represents the next selection
  6. Bookmark01-Represents the Bookmark name

Q.Explain 3-tier architecture of Qlikview Application? Ans: 1-tier: Raw data is loaded and we create QVD 2-tier: QVD is converted in business login and the requirement of business and data model is created. 3-tier: Reading all QVD from 2-tier and we make a single QVW. Q.How does Qlikview stores the data internally? Ans: Qlikview stores the data in QVD as QVD has data compression capability. Qlikview has better performance than other BI because of its memory analytics approach. Q.Explain the restrictions of Binary load? Ans: Binary Load can be used for only one application means we can only read the data from one QVW application and moreover set scripts is also a restriction. Q.Differentiate betwwen subset Ratio and Information Density. Ans: Subset Ratio: It is used for easily spot problem in key field association.it is only relevant for key fields since they are present in multiple tables and do not share the same value. Information Density: It is the field which contain the percentage of row which contain the non-null value. Q.what is the use of Optimized Load? Ans: Optimized load is much faster and preferable especially for large set of data. It is possible if n o transformation are made at the time of load and no filtering is done. Q.Differentiate between keep and joins? Ans: Keep and joins do the same functions but in keep creates the two tables whereas join only creates the one table. Keep is used before the load or select statements. Q.Define synthetic Key? Ans: Synthetic key is the key where two or more tables consists more than one common column between them is called as synthetic key. Q.What is incremental load in Qlikview? Ans: Incremental load is nothing but loading new or changed records from the database. With the help of QVD files we can use incremental Load. Q.Differentiate between set and let option in Qlikview?? Ans: Set: it assigns the variable without assesses the expression. Let: it assigns the variable with assesses the expression. Q.Define Qlikview Resident Load. Ans: Resident load is a part of loading data in Qlikview application. It is used for loading data in tables which is already loaded in Qlikview application. Q.How we can optimize QV application? Ans: It can be optimized by creating the data into qvds. When complete qvw application is changed into qvd than this qvd will be store in the RAM. Q.What is mapping load? Ans: Mapping load is used to create the mapping table that can be used for replacing field value and field names. Q.Define apply map. Ans: apply map is used to add fields to the tables with the help of other tables. It can be used as joins. Q.What is concatenation? Ans: It means sequence of interconnected things i.e. any column or row which is related to each other can be connected through concatenation. Q.Define NoConcatenation. Ans: NoConcatenation prefix is used to forced the identical tables as two separate internal tables. Q.Define connect statement. Ans: It is used to establish a connection the connection to database with the help of ODBC or OLEDB interface. Q.What do you understand by Fact constellation Schema? Ans: It is a logical database structure of data Warehouse . It is design with the help of De Normalized Fact.. Q.What do you mean by RDBMS? Ans: It stands for relational Database management System. It arrange the data into respective column and rows. Q.What do you understand by the term CAL in Qlikview? Ans: Every client need a CAL to get connected with Qlikview Server. The CALS are taken up with Qlikview Server and tied with the server serial number. Q.Differentiate between QV server and publisher? Ans: QV Server is a program that is installed on computer with various CALS which allow user to access QV Files on the server. Publisher is a program which manages centralized control on our QV files and manages them how and when the are loaded and distributed. Q.What do you understand by snapshot view of the table? Ans: By this option we can see number o tables and related associations. Q.How we can bring data into qv? Ans: We use ODBC, OLEDB, SAP connectors kind of data connections. Q.How we can handle Early Arriving Facts. Ans: We can load data from ODBC, OLEDB, SAP connectors , by select statements and we can also load files like excel, word, etc. by using Table Syntax. Q.What type of data we generally use? Ans: We use flat files, excels, QVDs, etc ad data. Q.Explain about QlikView? Ans: QlikView is the Business Intelligence tool used by the University of St Andrews. Data from different University systems is combined and presented in a single dashboard in an easy and understandable way. QlikView dashboards at the University of St Andrews are built on the following principles:

  • Dashboards must be effective to use
  • Dashboards must support users in carrying out their tasks
  • Dashboards must provide the right kind of functionality
  • It must be easy to learn how to use a dashboard
  • It must be easy to remember how to use a dashboard
  • To use QlikView, you do not need to have technical expertise in information systems, just a willingness to learn how it can support you.

Q.What are the benefits of using QlikView? Ans: As the name suggests, QlikView is a combination of quick and click and these features make it intuitive and easy to use. Users can visualize data, search multiple data sets, create ad hoc reports, and view patterns and trends in data that may not have been visible in other reports. QlikView is

  • Flexible – dashboards are web based and accessible from desktop computers and mobile devices
  • Interactive – users are able to drill down and select particular data within charts or tables
  • Usable – users can see large amounts of data effectively and efficiently
  • Scalable – useful for multiple business processes at analytical, operational and strategic levels

Q.How is QlikView 11 different from QlikView 10? Ans: QlikView 11 brings new levels of capability and manageability to the QlikView Business Discovery platform. In this release, we focused our investments on five value propositions:

  • Improve collaborative decision making with Social Business Discovery
  • Gain new insights into opportunities and threats and relative business performance with comparative analysis
  • Expand QlikView usage to additional devices, including smartphones, with mobile Business Discovery
  • Enable a broad spectrum of users to jointly develop QlikView apps with QlikView’s rapid analytic app platform capabilities
  • Improve the manageability and performance of QlikView with new enterprise platform capabilities.

Q.What is QlikView comparative analysis? Ans: Business users can quickly gain new kinds of insight when analyzing information in QlikView, with new comparative analysis options. App developers can now create multiple selection states in a QlikView app; they can create graphs, tables, or sheets based on different selection sets. Q.What mobile device platforms does QlikView 11 support? Ans: QlikView 11 delivers mobile functionality for Apple iOS and Android tablets and smartphones. QlikView supports Android tablets when the following conditions are met:

  • QlikView Server version 10 SR3 or later
  • The native browser, not a downloaded one
  • Currently our HTML5 web apps support only Apple and Android handhelds. Because many Black Berry are older devices that don’t fully support HTML5 (and many are non-touch), we don’t have a web-based solution for them at this time.

Q.What is document-level auditing in QlikView 11? Ans: New optional settings within QlikView Management Console enable administrators to more effectively audit user interactions. Administrators can audit QlikView usage not only at the system level (the entire QlikView Server), but down to the document level. Q.What are the key differences between QlikView and any other standard statistical software package (SAS, SPSS)? Ans: Key difference is in terms of the database used. QlikView offers a quite simple visualization that matches the MS excel filtering. SAS is useful in case of Meta data while SPSS is good for analysis. In comparison of the above three, QlikView is most user friendly and fast in terms of generating diverse dashboards/templates. In terms of calculations, advanced statistics options are limited in QlikView. For market research and analysis SPSS has direct facility algorithms. Q.What are QlikView annotations? Ans: With the new annotations collaboration object QlikView users can engage in threaded discussions about QlikView content. A user can create notes associated with any QlikView object. Other users can then add their own commentary to create a threaded discussion. Users can capture snapshots of their selections and include them in the discussion so others can get back to the same place in the analysis when reviewing notes and comments. QlikView captures the state of the object (current selections), as well as who made each note and comment and when, for a lasting record of how a decision was made. Q.What are the main features of QlikView? Ans: QlikView offers the following features:

  • Dynamic BI Ecosystem
  • Data visualization
  • Interacting with dynamic apps, dashboards and analytics
  • Searching across all data
  • Secure, real-time collaboration

Q.What are the differences among QlikView Server editions? Ans: The differences are: QlikView Server Enterprise Edition (EE) is available for customers looking to support a large number of users and integrate into enterprise environments. It includes features such as:

  • Unlimited documents
  • Integration with third party security systems
  • Server clustering
  • Small Business Edition (SBE) is designed to be used in smaller deployments.

It has the following limitations:

  • For use only with Named and Document CALs
  • Limited to 25 Named User CALs
  • Limited to 100 Document CALs
  • No support for additional servers
  • Only supports Windows Active Directory to handle security and access control

Information Access Server (IAS) is an edition of QlikView Server designed to power public Internet sites. This edition:

  • Includes the add-on QlikView Real Time Server
  • Is licensed for uncapped number of user but limited to one QlikView document
  • Must be set to anonymous mode only and authentication must be off
  • Requires that the QlikView server be on the public Internet and publicly accessible
  • Requires that the URL for accessing the site powered by the QlikView Server be publicly accessible
  • Requires that no QlikView client (e.g., QlikView Desktop, Internet Explorer plug-in, Ajax) can access the QlikView Server (all user interfaces must be built by the customer manually or with QlikView Workbench)

QlikView Extranet Server (QES) is an edition of QlikView Server designed to extend QlikView functionality to external users via an extranet. QES:

  • Requires authentication. Users must be external to the purchasing organization (customers, partners, etc.).
  • Restricts server access to the Ajax client and mobile clients
  • Provides the option to customize the QlikView application via the included QlikView Workbench
  • Supports a maximum of 3 QlikView documents
  • Supports session CALs and usage CALs only

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