QlikView Interview Questions and Answers – Clear Basic Concept
1. Top Most QlikView Interview Questions and Answers
We have learned all QlikView Basic Interview Questions in part-1. In this part, we will cover all basic concepts with all these QlikView Interview Questions and Answers. This article helps you to crack QlikView developer interview and many other.
No one can crack the Interview without knowing the basic concepts, through this QlikView Interview Questions and Answers, you can get all the basic and necessary information.
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2. Commonly Asked QlikView Interview Questions and Answers
Following are the top QlikView Interview Questions and Answers, let’s discuss them:
Q.1. What are Aggregate functions?
Aggregation functions are the functions that aggregate or bundle your data present in the rows of the table. You can apply mathematical or statistical operations collectively on large data chunks using aggregate functions.
Q.2. What are the 6 different types of Aggregate functions?
Six types or categories of aggregate functions are; Basic, String, Counter, Advanced, Statistical and Financial Aggregate Functions.
Q.3. Explain min() and max() aggregate functions.
The min() aggregate function returns the minimum numeric value from the set of values evaluates.
On the contrary, max() function returns the maximum numeric value from the set of data values evaluates.
Q.4. What is the difference between the string aggregate functions MinString(), MaxString() and FirstValue(), LastValue()?
All four of these functions apply on the string values. The MinString() function returns the first text value form a column/field irrespective of the order in which it loads. Similarly, MaxString() returns the last text value form a field irrespective of the load order. Like if the field in Months, then MinString() returns January and MaxString() returns December.
Whereas, FirstValue() returns the first value that was loaded (i.e. it follows the load order) and LastValue() returns the last value in load order.
Q.5. What do you understand by Kurtosis() and Skew() functions?
Kurtosis() and Skew() are a type of statistical aggregate functions. Kurtosis() measures the peak of a frequency distribution curve. Whereas, Skew() measures the symmetry in a statistical distribution curve.
Q.6. What does QlikView Aggr() function do?
The Aggr() or Aggregation function will aggregate over the set of possible records defined by the selection and returns a value resulting from the calculation performed on the data set.
Q.7. Explain QlikView IntervalMatch() and Match() functions.
QlikView IntervalMatch() function matches a value from one table with an interval or time value in another table. That is, you can compare the difference in time values in two tables.
QlikView Match() function matches a string expression value with other relevant values. It is more like an advanced search which uses for filter the required data through script command.
Q.8. What are the two types of Match() function?
QlikView Match() function is of two types; Match() and Wildmatch().
The difference between both is that in Match() function the entire string has to type as it is for the system to search it. Like, if you want to search the data in the filed Regions, then you must type the expression like,
Match(Regions, ‘Europe’,‘South Asia’).
But in the case of Wildmatch() full strings aren’t to type, instead of wild characters can use for searching.
Wildmatch(Regions, ‘Eu*’,‘S* As*’)
Q.9. What do you understand by Rangesum() function? How is it different from the Sum() function?
Rangesum function is used to calculate the sum of a selected set of data or a range of data. The Sum() function can’t apply on a selected lot of data values but the whole of it. Whereas Rangesum() can use according to your preferred set of data and can apply within other function expression and can return the sum of the expression as well.
Q.10. Discuss one scenario where you can use Rank() function.
Let us suppose that a car company wants to know the performance of countries in sales. For this, they would want to rank the countries based on sales occurred in them. For this we will use Rank() function on the total of sales amount for each country. The expression would look something like this, Rank(sum(Sales_in_country)). This would rank the countries from highest to lowest based on total sales value for each. If Australia had sales of 10,00,000 it will rank 1st. Then if the USA had sales of 9,80,000 then it will rank 2nd and so on.
We recommend you to read QlikView Interview and Answer Part – 3
3. Scenario-Based QlikView Interview Questions and Answers
These are the latest QlikView Interview Questions and Answers, helps you to get updated.
Q.11. What is ETL?
ETL is short for a data processing method i.e. Extract, Transform and Load. Data is extracted from the data source, transformed into user files and then finally loaded into QlikView for the users to use them.
Q.12. What is the difference between a list box and a multi box?
A list box displays all the values of a single table field in the form of a list. It is used to make selections of data values convenient. Whereas, a multi-box is a compressed table showing only the fields on display. You need to click on the Add sign to view data values of each field. So, the main difference between the two is that in list box you can only get one field displayed but in a multi-box all the fields can display.
Q.13. What is a text box used for?
A text box is used to display descriptive text to give information related to the data user is working with.
Q.14. What is a Mekko chart? Which sector are they most useful in?
Mekko charts represent data in the form of colored bars of varying sizes or width (according to the magnitude of data value it is representing). Such charts are used in business sectors specifically in market analysis.
Q.15. What is the fundamental difference between a block chart and a mekko chart?
Mekko charts represent data values as bars of varying sizes and width whereas block charts represent data values as blocks od varying areas.
Q.16. Explain Gauge charts.
A gauge chart in QlikView is used to display information like in a meter gauge. You can decide the highs and lows of values by looking at the gauge needle. Gauge charts display single expression or data value and not the entire dimension. You can put in different expressions for calculating percentage etc. The needlepoint of the gauge changes as soon as you make any selection in the table.
Q.17. What is a QlikView Dashboard?
QlikView’s dashboard is a document/sheet or collection of them consisting of different kinds of sheet objects containing the loaded data in QlikView. A user can conduct analysis on the data by representing and visualizing it in different ways and types of sheet objects on the dashboard.
Q.18. What are the different components of a dashboard?
Charts, Input Boxes, Selection Boxes, Buttons, Texts or list box Objects, Notes & Comments.
Q.19. What is the difference between SELECT and LOAD statements?
Both the statements are used to load data from external sources into QlikView. However, they are fundamentally different and are used in different situations.
LOAD statement used to load data from all sorts of files, from previously loaded data, inline data, autogenerated data. Whereas, SELECT statement use to load data from ODBC or OLE DB data sources. The statements using SELECT are not evaluated by QlikView but evaluates by the ODBC drivers or OLE DB providers.
Q.20. What are the operations that could perform on the data in a Transformation Wizard?
Data can transform in five ways in a transformation wizard,
Garbage, Fill, Column, Unwrap, Rotate.
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4. Advance QlikView Interview Questions and Answers
These are the QlikView Interview Questions and Answers for Experienced.
Q.21. What does the Garbage tab do in a transformation wizard?
The garbage tab, use to delete the unwanted rows in a table.
Q.22. What function must you choose to add columns in a table?
This can be done from the ‘Column’ function of the transformation wizard. Using this function, a new column can add into the table and values from pre-existing fields can enter in the newly added column.
Q.23. What does the Unwrap function do?
The Unwrap function undo the operations performed by the Wrap function. The wrap function takes the bottom half of a table and puts it adjacent (on the right section) of the first half. Whereas, the unwrap function takes this right section of the table and puts it back below the upper section of the table.
Q.24. What are the Dimensions?
In a table, Dimensions are always the descriptive text values. The fields with informative values like ID, product name, country, category are all Dimensions.
Q.25. What are Measures?
Measures are all the numerical values or fields in the table upon which mathematical calculations can perform.
Q.26. What is a Star Schema?
A star schema is a way of representing a data model which has a central fact table to which individual dimension tables link. It is a relational database model which represents a multi-dimensional database. It calls as a star schema because the entity relationship diagram of the fact table and dimension table looks like a star.
Q.27. Why is the formation of a Synthetic key considered bad in QlikView?
In QlikView, if there are several fields in common between two or more than two tables then a table containing the set of composite keys is made. This table is identified by a synthetic key ($Syn key).
However, this approach by QlikView to manage overriding fields consider as a sign of poorly designed data model. The user must check for logical errors that in turn reflects into the script not making a good data model.
Q.28. How can data generate automatically in QlikView?
QlikView provides a feature called Autogenerate which use for generate data using system’s programming.
Using Autogenerate, QlikView’s software creates data automatically following a few commands. Such data which autogenerate create not load from an external source but create unique. Autogenerate might generate data like 20 random numbers, dates of 15th week of the year, date and days from the current date to the last of the year etc.
Q.29. What are the different types of tables in QlikView?
There are different types of tables which can use to represent data in a tabular structure. The types of tables available in QlikView are; Straight table, Pivot table, Mapping table, Cross table and a simple table sheet object.
Q.30. What is a cross table? How is it different from transposing a table using a Rotate function?
In a cross table, the rows and column switch places from the state they originally were in. In such a table the data values of rows/records repeat themselves for each corresponding column value (if needed). This is not so in the case when we transpose a table using a Rotate option in the Transformation Wizard.
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QlikView Interview Questions Part – 5