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Sunday, October 4, 2015

QlikView Interview Questions (QlikView FAQ'S) - Part 2

QlikView Interview Questions (QlikView FAQ'S) - Part 1

 What is the difference between ODBC, OLE DB & JDBC?
o    ODBC : will use to connect to RDBMS databases
o    OLEDB : will use to connect to RDBMS databases and physical files as well
o    JDBC :
77. What is the use of Crosstable prefix in QlikView Load Script?
o    Crosstable : used to convert columns data to rows data

78. What is Mapping Load & ApplyMap() ?
79. What is the difference between Map Using and Mapping Load?
o    Mapping table used to create mapping data whenever different types of input data expected
§  U.s, u.s.a, united states à U.S.A
o    Data cleansing performed by using Map using
80. Synthetic Keys in QlikView and how & when to avoid them?
o    Synthetic keys are generated whenever you are joining two tables which are having 2 or more common key columns then Synthetic table going to be created based on common key columns.
o    These keys are referenced in related tables.
o    Avoid Synthetic keys by using below ways:
§  Renaming field names
§  Dropping/commenting field names which are not required
§  Qualify and Unqualify options
§  Joins
§  Concatenation
81. Different flavors of Joins in QlikView?
o    Inner Join
o    Left Join
o    Right Join
o    Outer Join (or Join ) à Default join
82. Different flavors of KEEP in QlikView?
o    Inner Keep
o    Left Keep
o    Right Keep
83. What is the difference between Join & Keep?
o    Join : combines the results based on key column and generates single output
o    Keep : combines the results based on key column and generates individual tables
84. Difference between Join and Concatenate?
o    Join : will combines the data horizontally
o    Concatenate : will combines the data vertically
85. How do you use Having clause (SQL Equivalent) along with Groupby in QlikView?
86. What is Peek, Previous, Apply map, Interval Match
87. Explain IntervalMatch function in QlikView?
A special case is when you need to generate all combinations between a numeric field, e.g. the date of an event or a transaction and numeric intervals defined in another table. In SQL, you would solve this by joining the two tables and use a BETWEEN condition:

SQL SELECT Events.Date, Intervals.BeginDate, Intervals.EndDate FROM Events, Intervals
WHERE Events.Date BETWEEN Intervals.BeginDate AND Intervals.EndDate;

In QlikView you would normally use the IntervalMatch prefix to solve this problem. The general structure of the script would be to first load the events table and the intervals table as they are, and then generate a third table defining a bridge between the two.

Load TransactionID, Date, <OtherEventFields> From Events;
Load IntervalName, BeginDate, EndDate, <OtherIntervalFields> From Intervals;

IntervalMatch (Date)
Load distinct BeginDate, EndDate Resident Intervals;

88. Explain Concatenation, No Concatenation & Auto Concatenation?
o    Concatenation :  forcible concatenation
o    No Concatenation : to stop automatic concatenation will use NoConcatinate qualifier
o    Auto Concatenation : whenever tables are having same no. of columns with same name then automatic concatenation going to happen
89. Explain how to implement Incremental Load?
90. How can you implement SCD in QlikView? Explain in Detail?
91. Binary Load, Preceding Load, Partial Load
92. What is Circular Loop and how do you avoid it?
93. Explain Exists() function in QlikView and when do you use this function?
94. What is Generic Load in QlikView?
95. How many ways you can maintain to store the QVD’s
o    Using Store
o    Using Buffer
o    Export option from Layout window
96. What is use of BUFFER Keyword in Qlikview ?
o    Buffer is used to generate .qvd files from QV document with buffer default location.
97. Can you store specific fields from loaded table to QVD?
o    Yes
98. What is Fuzzy search
99. What is Link Table and when is this used?
100.       What is subfield() and if we use that on several fields what is the result ?What is Substring?

101.       How to develop master templates (Common header and footer)
102.       Explain Aggr Function?
103.       What is Alt() function and its usuage?
104.       What is the use of FirstSortValue in QlikView?
105.       What are Set Modifiers and Set Identifiers?
106.       What is P() & E() and where do you use them?
107.       What is Partial Reload? and why do you use “ONLY” Qualifier?
108.       What is the difference between Cyclic Group & Drilldown Group?
109.       Explain alternate states and where do you use them?
110.       How many dimensions are used in Guage Chart
111.       Have you Create Ad hoc reports in your project And how
112.       Any knowledge about Data Island
113.       Conditional enabling of controls
114.       String Functions
115.       How many dimensions can be used in Bar chart?
o    2
116.       Which QlikView object has only expression, no dimension?
o    ListBox
o    Guage chart
117.       What is Comparitive analysis?
118.       What is Mekko chart and what is the difference between bar and Mekko chart?
119.       What is the difference between Pivot, Straight and Table box?
120.       How to refresh dashboards periodically?
121.       How you optimize QlikView dashboards?
122.       How you test your Dashboard?
123.       What’s the difference between the following expressions:
vVariable, $(vVariable) and $(=vVariable) ? Which one to use when?
124.       What’s considered “Safe” vs. “Unsafe” use of AGGR within a chart?
125.       What’s the difference between DISTINCT and NODISTINCT AGGR?
126.       How is AGGR different from TOTAL?
127.       Imagine you are displaying KPI results, color-coded with Red, Yellow and Green. Can you count the number of Red results, vs. Yellow, vs. Green, and show the totals in a summarized table?
128.       If you are using Set Analysis in a nested aggregation with AGGR, where do you need to place the Set Analysis condition?
129.       What’s the best way to visualize variance from average, along with standard error? How does average differ from median?
130.       How do you create a chart with a dynamic callout on a specific Dimensional Value?
131.       What is FieldValue() ? What is the restriction on this function?
132.       Have you plotted the Trellis Bar Chart and Stacked Bar Charts?
133.       How many maximum Dimensions we can use in Different Charts?
134.       limits of different chart types:
135.       Describe Section Access architecture?
136.       What is the difference between Authentication & Authorization in QlikView? And how to implement them?
137.       What is the difference between File System Security vs. Section Access?
138.       Explain “Strict Exclusion” while implementing Section Access and what are the implications of not using this option?
139.       How do you implement Section Access on hierarchy based data?
140.       DMS authorization
141.       Section Access
142.       Types of authorization in QlikView?
143.       What are the different types of CALs available?

144.       What are the multiple protocols defined for client communication with QVS?
145.       Explain different communication encryptions for Windows Client & AJAX Client?
146.       What is the use of Anonymous User Account in QVS?
147.       What are the different types of CALs and explain them?
148.       What are the different editions of QlikView Server?
149.       Different types of deployment of QV Reports?
150.       What are the different formats supported while doing export?
151.       How to change the paths of physical data files, database connections after deployment?
o    SIT, UAT and Production
152.       How to perform unit testing? Do we have any framework support?
153.       How to handle exception handling, logging.
154.       How to get the data from web services or Sales force or SharePoint?
155.       Do we have any restrictions on data sources?
156.       How to calculate the RAM size which is required for the project?
157.       How many ways we can share the reports with business users?
158.       Do we need to take extra precautions while deploying to mobile device? How to support mobile device?
159.       Default document settings for viewing the reports properly on IE or pdf….?

QlikView Interview Questions (QlikView FAQ'S) - Part 1

Qlikview developer, Designer and admin interview questions

(Qlikview developer, Designer and admin FAQ’S)

1. Difference between Set and Let?

Set : used to assign/concatenate text values
Let : used to assign expressions

2. Difference between Sum() and RangeSum()?
Sum : Sum(field name)
RangeSum :
 RangeSum(expr1 [ , expr2, ... exprN ]) Returns the sum of a range of 1 to N arguments.
 As opposed to the + operator, rangesum will treat all non-numeric values as 0. The argument expressions of this function may contain Chart Inter Record Functions with a third optional parameter, which in themselves return a range of values.
 RangeSum (1,2,4) returns 7
 RangeSum (1,'xyz') returns 1
 RangeSum (null( )) returns 0
 RangeSum (above(count(x),-1,3)) returns the sum of the three results of the count(x) function evaluated on the row below the current row, the current row and the row above the current row.
 RangeSum(Above(Sum(Amount),0,RowNo()))  In this your accumulation starts from 1st value which it writes as it is. because you write the 0 for that value and then for others value in row it accumulates.
 RangeSum(Above(Sum(Amount),1,RowNo()))  in this your cumulative starts from 2nd row and it will make first row as zero.
 RangeSum(Above(Sum(Amount),-1,RowNo()))  in this case it pick up 2nd value for accumulation means takes two values to be accumulated in my example first it take 20 then 20+30 acc. to condition and add 20 above gives 70 then it gives you then it takes 70 accumulate then 30 and 50 gives you 150 and then gives 110 because of adding 50 and 60 and then 60 so on…

3. Difference between Info Load and Bundle Info?

Info Load: used to link the external resources (Ex: Images, media files…) to the Internal data table.
Bundle Info: Purpose is same as Info Load
Preferred when changes are expected at external files location
1st time link the data from external files location and next time onwards it will refer from memory

4. Difference between Internal Table Viewer and Source Table Viewer
o Internal Table View is the default view. It shows the data tables as QlikView stores them. Composite synthetic keys are formed in tables that share more than one field. Synthetic tables are used to link them. This view offers the best understanding of the QlikView logic and also provides a very clean layout where each pair of tables has a maximum of one connector between them.
o Source Table View shows data tables as QlikView reads them. Here there are no synthetic fields or synthetic tables. Composite keys are represented by multiple connectors between tables.
5. Difference between Recno() and Rowno()?

 The RecNo() function will return an integer for the record currently being read from the source table starting with number one. The RowNo() function also returns an integer but it represents the position of the row in the resulting QlikView internal table.
 So while RecNo() counts from the source table, RowNo() counts from the resulting table.
 The RecNo field indicated the order in which the records were read from the source table and the RowNo field indicates the position of the record in the internal table.

6. Difference between P() and E()?

o Both functions p () and e () have the same syntax:
o p () returns the possible values, the other e () returns the excluded values.

7. Difference between ApplyMap() and Lookup()?

8. Difference between ValueList() and ValueLoop()?

9. Difference between Peek(),Pick() and Previous?

10. Difference between Pick and Match?

o The Pick function will return the expression/value corresponding to the expression that matches the first parameter. For example, Pick(2, ‘A’, ‘B’, ‘C”) will return B because B is the second expression and Pick(Number, Sum(1+1), Sum(2+2), Sum(3+3), Sum(4+4), Sum(5+5)) will return 6 if Number = 3. This function is excellent when you want to generate a random field value, e.g.

11. Ragged Hierarchies in Data warehousing
12. What are slowly changing dimensions?

13. Have you used Alternate states and why?
• Most businesses need comparative analysis to identify the state of the business. QlikView Alternate States was introduced in version 11 to facilitate comparative analysis such as year-over-year sales comparison where users want to see how current year sales compares to the previous year or current quarter compares to the same quarter a year ago.
• Most of the cases using only Line chart or bar chart using QV.

14. What is Set Analysis (benefits of using it)? Why it’s called Set Analysis

15. How to connect to Database?

o By using Connect button (under Data tab) from script window using ODBC/OleDb connector
o Select DSN (data source name)
o Select button to load the tables from database

16. What are the various data sources for QlikView?

o Database
 RDBMS – MS Access, Sql Server, Oracle….
 DB2,
o Data Files
 Raw data files : .xlsx,.xls, .csv,.txt, .xml
 QlikView files : .qvd
o Web Files : Web services…
o Salesforce,... using third party connectors

17. What is partial reloading?
18. What care should be taken while designing a data model?
19. What are the two main techniques of combining Fact Tables, and the differences between the two?
20. How can you work with Slowly Changing Dimensions in QlikView?
21. How can you organize an efficient Delta Load, in a variety of data scenarios?
22. How should you structure your code using subroutines and functions?
23. Where do you create Dimension and Measure tags? How are they useful?
24. What is concept of Alternate States? Syntax for using in Set Analysis?
25. What are the different File Functions and QVD functions?
26. What are Value List and Value Loops?Tell me with scenarios?
27. What is Rand() ,Autonumber() and Autogenerate()?
28. What are Circular References?How do you avoid them?
29. What are Information Density and Subset Ratio?
30. Explain me with scenarios of Primary Key and Perfect Key?
31. What is First Value and FirstSorted Value()?
32. Tell me how to use Qualify and UnQualify?
33. What are the different Error Modes? What are the different Script Errors?
34. Have you Used Bubble Sort? In which scenario we should use?
35. What is Aggr() and Dual() ?
36. Why Sum() is better than Count()?
37. List some Better Practices that you have used in your Work?
38. Have you worked on reading Done Files? How do we handle them?
39. Tell me how can we work Insert, Update and Delete on Incremental Loads?
40. What is 3 Value Logic in QlikView? Can you elaborate in Detail?
41. Have you used Include and Config files? Can you write sample scripts for each?
42. Explain about the Section Access in brief and important setups we need to do?
43. What is Custom Sort and have you ever tried to implement?
44. What is the RAM Size and Processor of your RAM? What is the Application Size?
45. Have you implemented Waterfall Chart? How do we implement them?
46. Explain me how do we connect to OLEDB Connection?
47. What is Custom Format in QlikView?
48. If I Want to Skip specific rows in Excel during Load how do we need to do that?
49. Brief me about Set Analysis? Tell me script to compare the Sales of this year to Last Year?
50. Explain me about Source and User Documents in QMC?
51. Explain me some steps to improve Performance in Scripting and GUI?

52. What are the Data Types available in QlikView?
o There are no data types in QlikView :)
53. Functions in Qlikview

o RecNo() – the record number of the input record
o RowNo() – the record number of the output record
o Rand() – a generator of random numbers,
o Ceil() – round upwards to nearest integer,
o Pick() – pick a specific value in a list of values
o …

54. Load statement in different ways:

a) Load … From File ; (from file)
b) Load … Resident Table ; (from an already loaded table or from in-memory tables or internal tables)
c) Load … Inline InlineTable ; (from a table written in the script)
d) Load … Autogenerate Number ; (from nothing)

o But with autogenerate there is no source – the records are generated and all field values must be derived from functions like Rand() or RecNo(). The number of records is specified in the number after the Autogenerate keyword.
55. How to display a list box as a horizontal list box?

o List Box --> Properties --> Go to Presentation Tab --> UnCheck Single Column
o You can also set the number of columns you want to view horizontally buy checking the Fixed Number of Columns tab and entering a value in the associated box.
o "Order by Column" needs to be unchecked (optional)

56. QlikView vs QlikSense
o QlikView is a tool for situations where you want prepared business applications, i.e. applications created by developers who put a lot of thought into the data model, the layout, the charts and the formulae; and deliver the applications to end-users who consume the applications. We call this Guided Analytics. The end-user has total freedom to explore data, select, drill down and navigate in the information, and can this way discover both questions and answers in the data. The end-user is however limited when it comes to creating new visualizations. This type of situation will without doubt be common for many, many years to come.
o Qlik Sense is a tool for situations where you don’t want to pre-can so much. Instead you want the user to have the freedom to create a layout of his own and in it, new visualizations; charts that the developer couldn’t imagine that the user wants to see. You want Self-service data discovery, which means a much more active, modern, engaged user. In addition, Qlik Sense is much easier to use when you have a touch screen, and is adaptive to different screen sizes and form factors. On the whole, Qlik Sense is a much more modern tool.

57. Optimized and unoptimized QVD Load Situations?
58. Best data modeling techniques
59. What are the common steps in every Data Modeling process?
60. Explain 3 tier architecture implementation while deploying QlikView application?
61. Briefly explain how does QlikView storage the data internally?
62. What are the restrictions of Binary Load?
o Only one Binary statement for the script and that should be initial statement

63. How are NULLS implemented in QlikView?
64. How do you optimize QlikView Application? (What tools are used and where do you start?)
o Whenever the tables contain huge data then we have to store it into QVD files (compressed format).
o If using large data base file try to create the incremental load for the QVD or load latest data only.
o Load only the required fields into QlikView from different data sources.
o Data Model: QlikView can analyze multiple data sources but works most efficiently with Star Schema or Snow flake Schema. The Star Schema Consists of few fact tables possibly only one ,referencing any no. of dimension tables
o User Interfaces:
 Resource intensive expression like count(distinct) if() should be avoided. Set analysis should be used instead.
 Complex script should be done in script rather than in charts/tables.
 Macros should be replaced by built in QV functions.
 Expressions which are used frequently in more than one chart/table should be stored in a variable which reduces the calculation time.

65. What is the difference between Subset ratio & Information Density?
66. What type of architecture are you using in your project

67. What type of schema are you using in your project? And why
o Star schema
o Snow Flake Schema
68. How many charts are you used till now
69. Have you used macros in your project and why? No
70. Difference between QV versions?

• QMC and QEMC are taken as one QMC.
• Comparative analysis ( Alternative State)
• Expand QlikView usage to additional devices, including smart phones, with mobile Business Discovery.
• Granuler chart dimension is introduced in Qv11.
• Dimension Limits tab also included.
• QlikView 11 introduces important changes to the QlikView Publisher component.
• AccessPoint Redesign Helps IT Better Support Business Users.
• Container object enhancements
• Conditional enabling of dimensions and expressions improves the user experience.
• Annotations improve context and establish a record of how decisions were made.

71. Explain the QV Development Life Cycle till the User Visualizes the Dashboard?
72. Explain the Folder Structure we follow during the development and Folder Structure in QMC?
73. Explain EAV data modeling technique?
74. Difference between Star Schema & Snow Flake Schema?
75. Difference between RDBMS & Associative Database?

Refer for : QV FAQ's Part2

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