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Top 100 Tableau Questions and Answers for Job Interview

1)What is Tableau?

Answer: Tableau is business intelligence software that allows anyone to connect to data in a few clicks, then visualize and create interactive, sharable dashboards with a few more. It’s easy enough that any Excel user can learn it, but powerful enough to satisfy even the most complex analytical problems. Securely sharing your findings with others only takes seconds. The result is BI software that you can trust to actually deliver answers to the people that need them.

2) What do you mean by Data Visualization?

Answer: Data visualization can be defined as the process of describing information through visual rendering. Humans have been using visualizations to explain the world around them for millions of years. Data visualization allows for universal and immediate insight by tapping into our mind’s powerful visual processing system.

3) Mention the importance of data visualization.

Answer: Technological advances have made data visualization more prevalent and powerful than ever before and hence have caused an increase in the importance of business intelligence. Tableau leads the world in making the data visualization process available to business users of every background and industry. Businesses around the globe realize that the ability to visualize data effectively leads directly to better understanding, insight and better business decisions. Tableau is a piece of Software that enables businesses to keep pace with the evolving technology landscape and outperform competitors through an adaptive and intuitive means of visualizing their data.

4) What do you know about the Tableau Desktop?

Answer: Tableau Software provides software applications for fast analytical and rapid fire business intelligence. The Tableau Desktop is a data visualization application that lets the user analyze virtually any type of structured data and produce highly interactive, beautiful graphs, dashboards, and reports in just minutes. After a quick installation, user can connect to virtually any data source from spreadsheets to data warehouses and display information in multiple graphic perspectives. Designed to be easy to use, the user will be working faster than ever before. Tableau Server is a business intelligence solution that provides browser-based visual analytics anyone can use at just a fraction of the cost of typical BI software. With just a few clicks, user can publish or embed live, interactive graphs, dashboards and reports with current data automatically customized to the needs of everyone across your organization. It deploys in minutes and users can produce thousands of reports without the need of IT services — all within the inbuilt IT infrastructure. Tableau Reader is a free viewing application that lets anyone read and interact with packaged workbooks created specifically by the Tableau Desktop.

5) How does one create a dashboard in Tableau? What is the life cycle of a dashboard?

Answer: A dashboard can be defined as a collection of several worksheets and supporting information shown in a single place so that user can compare and monitor a variety of data simultaneously. For example, there may be a set of views that user has to review every day. Rather than flipping through each worksheet, user can easily create a dashboard that displays all the views at once.

Creating a dashboard is similar to the creation of a new worksheet. Follow the given to create one of your own:

Select Dashboard > New Dashboard. Alternatively, click the New Dashboard tab along the bottom of the workbook. A new tab for the dashboard is added along the bottom of the workbook. Switch to the new dashboard to add views and objects. When the user opens a dashboard the Dashboard window replaces the Data window on the left side of the workbook. The Dashboard window lists the worksheets that are currently in the workbook. As user creates new worksheets, the Dashboard window updates so user always have all worksheets available when adding to a dashboard it. After a view is added to the dashboard, the worksheet is marked with a check mark in the Dashboard window. Any legends or quick filters that are turned on for the sheet are automatically added to the dashboard. By default, dashboards use a Tiled layout, which means that each view and object is arranged into a single layered grid. User can change the layout to Floating to allow views and objects to overlap.

6) How to reschedule reports in Tableau?

Answer: Schedules are used when user publishes workbooks that connect to extracts that user specifically schedules to the extracts to be refreshed automatically. That way the user doesn’t have to republish the workbook every time the underlying data has updated and he/she can still get the performance of a data extract. For example, there is a workbook that connects to a large data warehouse that is updated weekly. Instead of publishing a workbook that queries the live data, user can simply create an extract including just the data necessary. This increases performance and avoids queries to the live database. Then the user can add that workbook to a schedule so that the extract is refreshed at regular intervals with updated data from the data warehouse. Schedules are created and managed on the server by an administrator. However, an administrator can allows the users to add a workbook to a schedule when they are publishing using the Tableau Desktop. As users are publishing a workbook, in the Publish Workbook to Tableau Server dialog box, one must click the Scheduling & Authentication. In the Scheduling & Authentication dialog box, the user can select a schedule for the workbook according to choice. All data sources that require authentication must have an embedded password so that the extract can be refreshed. This includes data sources that are not extracts.

7) When a user exports a worksheet into the Tableau server how does he/she give a connection to database to run that report in the server?

Answer: When the user publishes workbooks that connect to extracts he/she can schedule the extracts to be refreshed automatically. That way one doesn’t have to republish the workbook every time the underlying data has updated and user can still get the performance of a data extract.

For example, consider a workbook that connects to a large data warehouse that is updated weekly. Instead of publishing a work-book that queries the live data, the user can create an extract including just the data that is necessary. This increases performance and avoids queries to the live database. Then the user can add that workbook to a schedule so that the extract is refreshed at regular intervals with updated data from the data warehouse. Schedules are created and managed on the server by an administrator. However, an administrator can allow the user to add a workbook to a schedule when he/she is publishing from.

8) Mention the differences between the 7.0 and 8.0 versions of Tableau.

Answer: New visualizations have been introduced in Tableau 8.0 such as tree map, bubble chart and box and whisker plot. The user can simply copy worksheet directly from one workbook to another workbook. The introduction of the R script in tableau 8.0 was also a great addition. All these facilities enhanced Tableau 7.0 and caused the birth of Tableau 8.0.

9) What do you mean by parameters in Tableau? When do you use parameters in Tableau?

Answer: In Tableau, parameters are dynamic values that can replace constant values in calculations. The user can create parameters in 3 ways:

  • Filters
  • Reference lines
  • Calculate Field

10) Tableau has a major disadvantage due to its slow processing speed. What are the major issues that might cause a problem of this nature?

Answer: There are a number of reasons behind the poor performance of Tableau in terms of processing a result:

  • During the processing of a query, filters may not be defined appropriately at report level due to which the entire data set is pulled from the query. This might cause computational delay as the searching of the entire data set might not be required at all.
  • Creating a query that returns a large number of records from the underlying table, when a smaller number of aggregated records would have sufficed. This small feature can be checked by looking at the lower-left corner of the Tableau Desktop work space and looking at the number of marks. If this number is very large, the user is potentially pulling a large amount of data from the database
  • Use of native drivers is another common problem behind the slow processing of Tableau Queries. Tableau will recommend or require the user to create a data extract to continue working with a particular driver. Usage of native driver is recommended in the case instead of ODBC connections as the former will generally provide better performance.
  • A good way to determine if a slow workbook is being caused by a slow query is to test the same query in another tool, such as Microsoft Access or Microsoft Excel. This not only helps in judging the process speed but also helps in cross-checking the result.
  • The proper use of extracts helps in solving speed issues. Create a tableau extract if there are constant performance issuesThese extract files can include performance-oriented features such as pre-aggregated data for hierarchies and pre-calculated calculated fields. All these facilities prove to be beneficial in reducing the amount of work required to render and display the visualization.

The following methods can be used to handle this slow processing:

  • Tuning of indexes:
  1. The user must make certain that he/she has indexes on all columns that are part of table joins.
  2. Then it has to be make certain that he/she has indexes on any column used in a filter.
  3. Explicitly define primary keys.
  4. Explicitly define foreign key relationships.
  5. For large data sets, use table partitioning.
  6. Define columns as NOT NULL where possible.
  • Using statistics productively:
  • Databases engines collect statistical information about indexes and column data stored in the database. These statistics are used by the query optimizer to choose the most efficient plan for retrieving or updating that.
  • Optimization of the data mode: This feature is beneficial to create summary tables if most of your queries only need aggregated data – not base level details records.

11) Mention the difference between connect live and import all data and importing data.

Answer: The following heads can be studied to understand the difference between the given:

Connect live – This creates a direct connect to the concerned data. The speed of the data source will determine performance.

Import all data – This imports the entire data source into Tableau’s fast data engine as an extract. The extract is saved with the workbook.

Import some data – This imports a subset of the concerned data into Tableau’s fast data engine as an extract. This option requires the user to specify what data the user wants to extract using filters.

12) Explain the concept of Ad-hoc reports in Tableau.

Answer: An Ad-hoc reports points to the spot based on the client requirement by connecting to live environment that the user can create reports. Such reports are called Ad-hoc reports in Tableau.

13) Differentiate between a Quick Filter and a Normal Filter in Tableau.

Answer: In Tableau, a Quick filter is used to view the filtering options and can be used to select the option. Similarly, a Normal filter is something that the user can limit the options from the list or use some conditions to limit the data by filed or value.

14) How does Tableau work on a Mac?

Answer: Macintosh users can view the Tableau Public content in their browser. Tableau Desktop Public Edition used for authoring content is a Windows application only. If the user is using a Macintosh computer that has an Intel processor, he/she can use virtualization software such as VMware Fusion or Parallels Desktop to install Windows and run Tableau Desktop Public Edition. Alternatively, a user can use a built-in utility called Boot Camp to install Windows and run the Tableau software.

15) Does Tableau allow the automation of reports?

Answer: Yes. In order to automate any report in Tableau, the user needs to publish the concerned report to the Tableau server. While publishing, the user will find one option to schedule reports. Here, the user just needs to select the time when he/she wants to refresh the concerned data values.

16) What are the components if the dashboard in Tableau?

Answer: Some of the components of a dashboard in Tableau are Horizontal, Vertical, Text, and Images.

17) How is Tableau able to process so fast when used along with databases?

Answer: Tableau compiles the elements of the user’s visual canvas into a SQL or MDX query for the remote database to process. Since a database typically runs on more powerful hardware than the laptops / workstations used by analysts, the user should generally expect the database to handle queries much faster than most in-memory BI applications limited by end-user hardware. Tableau’s ability to push computation, queries in case of a database, close to the data is increasingly important for large data sets, which may reside on a fast cluster and may be too large to bring in-memory. Another factor in performance relates to data transfer, or in Tableau’s case result set transfer. Since Tableau visualizations are designed for human consumption, they are tailored to the capabilities and limits of the human perception system. This generally means that the amount of data in a query result set is small relative to the size of the underlying data, and visualizations focus on aggregation and filtering to identify trends and outliers. The small result sets require little network bandwidth, so Tableau is able to fetch and render the result set very quickly. Tableau will cache query results for fast reuse. The last factor as mentioned by Eriglen involves Tableau’s ability to use in-memory acceleration as needed. Tableau’s Data Engine uses memory-mapped I/O, so while it takes advantage of in-memory acceleration it can easily work with large data sets which cannot fit in memory. The Data Engine will work only with the subsets of data on disk which are needed for a given query, and the data subsets are mapped into memory as needed.

18) What do you mean by the Tableau Desktop?

Answer: Tableau Desktop is a data visualization application that lets the user analyze virtually any type of structured data and produce highly interactive, beautiful graphs, dashboards, and reports in just minutes. After a quick installation, the user can connect to virtually any data source from spreadsheets to data warehouses and display information in multiple graphic perspectives. Designed to be easy to use, the user is able to work faster than ever before.

19) What do you mean by the Tableau reader?

Answer: Tableau Reader is a free viewing application that lets anyone read and interact with packaged workbooks created by Tableau Desktop.

20) Mention the working steps of Tableau.

Answer: While Tableau lets the user analyze databases and spreadsheets like never before, he/she doesn’t need to know anything about databases to use Tableau. In fact, Tableau is designed to allow business people with no technical training to analyze their data efficiently. Tableau is based on three simple concepts:

Connect – Connect Tableau to any database that the user wants to analyze. Note that Tableau does not import the data. Instead it queries to the database directly.

Analyze – Analyzing data means viewing it, filtering it, sorting it, performing calculations on it, reorganizing it, summarizing it, and so on. Using Tableau the user can do all of these things by simply arranging fields of your data source on a Tableau worksheet. When the user drops a field on a worksheet, Tableau queries the data using standard drivers and query languages (like SQL and MDX) and presents a visual analysis of the data.

Share – The user can share results with others either by sharing workbooks with other Tableau users, by pasting results into applications such as Microsoft Office, printing to PDF or by using Tableau Server to publish or embed the user’s views across his/her organization.

21) Mention the cases when the horizontal and vertical components are used in Tableau.

Answer: Any user can use the horizontal and vertical components when he/she wants to have all sheets or filter to move in single shot. However, Tableau allows user to still create the dashboard without this also. This allows the users to make our work simple

22) What do you know about table calculations?

Answer: Table calculations are inbuilt calculations exclusively available in Tableau which the user normally uses to calculate the percentage from or to perform the YTD operation and other calculations like the measure across table, below table and etc.

23) How can the user find the Tableau Report Rendering Time?

Answer: The following formula can be used to find the Tableau Report Rendering Time:

Report rendering time=Network time(request from URL to Report server) +Query execution time + Network time(response from SQL Server)+calculations(table column)+time taken to display the report in desired format(HTML/ pdf/ excel)

24) What do you know about VizQL?

Answer: VizQL is a visual query language that translates specifically drag-and-drop actions into data queries and then expresses that data visually. VizQL delivers dramatic gains in people’s ability to see and understand data by abstracting the underlying complexities of query and analysis. The result is an intuitive user experience that lets people answer questions as fast as they can think of them. We believe that VizQL represents a foundational advancement in the area of data analysis and visualization.

25) Mention the advantages of Tableau for which it is used commonly.

Answer: There are many reasons that specify why one should use Tableau:

  • It is very easy to use:
  • The user doesn’t need to know programming of any sort to handle Tableau. All that the user needs is some data and Tableau to create reports that are visually enchanting and which tells a story which the user needs or wants to tell his/her managers or impress his/her professor in class.
  • With its revolutionary drag and drop feature the user can easily create stories or reports using external peripherals like the mouse and a little imagination. All this is possible due to the revolutionary VizQL a visual query language.

26) What are the various types of filters available in Tableau?

Answer: In Tableau, there are three types of filters. More explicitly, there are three different ways to limit the data that is displayed by your graph. Each of these filters has its own strengths and weaknesses. These types are:

Custom SQL Filters: Custom SQL Filter is a WHERE clause that is placed in the SQL that queries the data to be used in the workbook. Filter is a Tableau term that technically applies only to Context and Traditional Filters. However, the Custom SQL Filter emulates the behavior of a global Context Filter, so it is usually referred to it as such. By construction, Custom SQL Filters are always global. The most common reason for using a Custom SQL Filter is to limit the size of a data extract. The smaller is the size of data extract, the more quickly the concerned charts will load. In other words, the user can make more complex charts without sacrificing efficiency. One of the ways to create a Custom SQL Filter is during the Server Connection process.

Context Filters: A Context Filter is a filter in Tableau that affects the data that is transferred to each individual worksheet. Context Filters are great when the user wants to limit the data seen by the worksheet. When a worksheet creates a query from the concerned data source, it creates a temporary, flat table that is used to compute the chart. This temporary table includes all values that are not filtered out by either the Custom SQL or the Context Filter. Just like with Custom SQL Filters, the user’s goal is to make this temporary table as small as possible. Context Filters have a few advantages over Traditional Filters. First, they execute more quickly than Traditional Filters. They are also executed before Traditional Filters and can be executed all at once, which further improves efficiency. However, they do have one drawback. It takes time for the filter to be placed into context. A rule of thumb, from Tableau’s Knowledge Base, is to only place a filter into context if it reduces the data by at least 10%. A Context Filter is created by dragging a field onto the “Filters” Shelf and editing the filter. Then, the user can Right-Click the field on the shelf and select “Add to Context.” If he/she has multiple context filters, you can CTRL-Select them all and add them to context in a batch. This will improve the efficiency of your filter.

Traditional Filters: Traditional Filter is exactly what most people think of when they think of filters. When Tableau is creating the visualization, it will check to see if a value is filtered out by a Traditional Filter. Since this is not performed at the table level, it is the slowest of all filter types. However, it does have the advantage of being performed after the Context Filters. This is a necessity if you are dealing with complex “Top N” filters. A Traditional Filter can be created by simply dragging a field onto the “Filters” Shelf.

27) How can one improve performance in Tableau?

Answer: The following features can be used by the user to improve the performance in Tableau:

  1. Use an extract: There is nothing else that comes close to the efficiency gained using an extract. If the user doesn’t absolutely need live data, extracting is the best bet.
  2. Limit your dashboard to fully answering only one scenario: At it’s simplest, a dashboard should be able to fully explore a single scenario. If the user dashboard has six sheets, five actions, and 3 quick filters, the user might not be looking at only one scenario. Remember, no matter how elegant and comprehensive the user’s solution is, if it doesn’t run as quickly as the user would like it to, he or she will not use it. It is not recommended to butcher your dashboard so heavily that it cannot fully handle a scenario. If the user has to go somewhere else to find the answer, there is absolutely no reason to use your dashboard at all.
  3. Limit the data being introduced to each worksheet: If the user is not planning on using a set of rows, he/she should filter them out of the data set as early as possible. If the user’s table contains all sales, and the user only want to look at US sales, create a Custom SQL query that filters it out. If the filter is worksheet dependent, try using a Context Filter. The user can also click the Down Arrow beside the word “Dimension” and Select “Hide All Unused Fields” to hide any fields that the user is not using in any of your worksheets. I’m not sure if this improves efficiency; but I’d have to imagine that it does, less data should always improve performance.
  4. Remove components that add no value: While aesthetics are very important to building a usable dashboard, unimportant objects aren’t worth losing efficiency over. In fact, it is advised to the user that they would be better off adding more functionality than they would by adding a purely aesthetic object.
  5. Any non-essential components from the visualization: This refers to values that would appear on the Pages, Filters, and Level of Detail Shelves. If they are purely there for the user to see if they scroll over a point, then they aren’t adding any value to the initial glance. In most cases, a little forethought can save the user from a lot of heartache when he/she is creating dashboards. The user must decide exactly what story he/she wants to tell, and tell only that. It is much easier to add functionality to a small dashboard, than to butcher a large one.

28) What do you know about Tableau Public?

Answer: The free version of Tableau Public is for people. This includes writers, bloggers, students, professors, hobbyists, journeymen, critics, citizens and more. It can be easily used by organizations, but only as an introductory service. If a certain organization wants to put data online for the public, the company is welcome to use this as an introductory service.

29) Can Tableau be used to share data on a private blog or website?

Answer: Yes, Tableau can be used to share data on a private blog or website. The Tableau Public is to be used to share data and insights with the personal fanbase or community. Embed the content in the respective blog or website, or share it via links on web pages or in emails.

30) Does Tableau have a limit on storage space of data?

Answer: Yes, Tableau has a limit of 1 gigabyte on storage space for data. For the vast majority of users, it is expected that 1 GB will be more than enough space required.

31) Can Tableau be used to share a lot of data with the public?

Answer: Yes, Tableau can be used to share data from an organization to the public. This is applicable as long as the user and all other employees at the concernec organization together uses less than 50 megabytes of space. Tableau Public gives the respective organizations the freedom of only 50 MB unless an authorized version is purchased.

32) Mention the limitations on Tableau Public.

Answer: Tableau Public can connect to Microsoft Excel, Microsoft Access, and multiple text file formats. It has a limit of 1,000,000 rows of data that is allowed in any single file.

33) Does a user need the free desktop product if he/she already owns a commercial version of the Tableau Desktop?

Answer: No, such an arrangement does not need to be carried out. Tableau Desktop comes in three editions: Professional Edition ($1,999), Personal Edition ($999) and Public Edition (free). If any user already has Professional or Personal Edition, he/she will find that your latest upgrade includes the ability to publish to the Tableau Public servers. There is nothing in Public Edition that is included in the latest versions of the paid products.

34) Can any user set permissions or protect the data that has been saved to Tableau Public?

Answer: All content saved to Tableau Public is accessible to everyone on the internet. As the author, only the concerned user is the only one who can delete his/her own content, but anyone on the internet can view it. In addition to viewing it, anyone can download a copy of the respective workbook (including the underlying data) as well, which will let them work with and build upon the original.

35) Does data become public if published on Tableau Public?

Answer: Yes, any data on Tableau Public be default becomes accessible on the world-wide web and can be downloaded by anyone. It is strongly suggested that any user only publishes data that they are willing to share with anyone.

36) How can any internet surfer find the visualizations that have been saved to Tableau Public by a remote user?

Answer: Once the remote user saves his/her work to Tableau Public, it may be shared (by emailing a link or embedding the work in the blog, wiki, or website). If the user embeds the work onto a web page, anyone who visits the page will see the live interactive view. If the user emails a link, just by clicking the link will open a browser page with the view loaded.

37) What do you know about the Download Link in Viz?

Answer: Any Tableau Public in Viz can be downloaded by pressing the download link in the lower right corner. It saves to the user’s computer as a TWBX file. Anyone with Tableau Desktop (Professional, Personal or Public Edition) can open the file and review or extend the work that was behind the original posting.

38) What happens if a workbook is deleted from a Tableau Public and there are links to it in blogs or other web locations?

Answer: Once a workbook or view is deleted from Tableau Public, it cannot be retrieved from Tableau Public by anyone. All links or other references to it that may have been shared will not be able to load the concerned Viz application and will display an error message on the page.

39) What is the DIBO feature of Tableau?

Answer: DIBO is an acronym for Data In Brilliance Out in Tableau. This is the future vision for Tableau Public. It captures both goals of making Tableau incredibly easy to use and spectacularly powerful

40) What do you mean by a KPI in Tableau?

Answer: We can easily create a view that shows Key Progress Indicators (KPIs). To do this, copy the given steps:

  • Create the base view with the fields that need to be measured.
  • Build a calculated field that establishes the figure from which the progress will be measured for the data being measuring.
  • Use shapes that Tableau provides that are designed specifically for KPIs.
  • This example shows how to build a KPI view that shows a green check mark for any sales figure over $125,000, and a red X for any sales figure under $125,000.

Next up data needs to be prepared for Tableau. To do that, follow the given steps:

  • Cleanup dimensions and measure names.
  • Set attribute aliases.
  • Set default colors
  • Set default measure aggregations.
  • Create calculated fields

41) Mention the criteria to blend the data from multiple data sources.

Answer: There should be a common dimension to blend the data source into single worksheet. When a user is blending Actual and Target sales data, the two data sources may have a Date field in common. The Date field must be used on the sheet. Then when the user switches to the secondary data source in the Data window, Tableau automatically links fields that have the same name. If they don’t have the same name, the user can define a custom relationship that creates the correct mapping between fields.

42) Can the user make use of Sets and Groups in calculation fields? Mention the difference between the mentioned.

Answer: No, we cannot use Groups in calculation fields. Yes, we can use Sets in calculation fields.

Groups are used to combine dimension members into higher level categories.

Sets are used to create a custom field based on existing dimensions that can be used to encode the view with multiple dimension members across varying dimension levels.

 

43) What do you know about a context filter?

Answer: A context filter is applied to the data source first, and then the other filters are applied only to the resulting records. This sequence avoids applying each filter to each record in the data source. If the user is applying filters to a large data source, he/she can improve performance by setting up context filters.

44) How to create a context filter?

Answer: The user can create a context filter in more than one way:

  • Improve performance – If the user sets a lot of filters or makes a workbook that has a large data source, the queries can be slow. In such a case, the user can set one or more context filters to improve performance.
  • Create a dependent numerical or top N filter – The user can set a context filter to include only the data of interest, and then set a numerical or a top N filter.

 

45) What do you know about the Dual Axis?

Answer: The user can compare multiple measures using dual axes, which are two independent axes that are layered on top of each other. Dual axes are useful when the user has two measures that have different scales. For example, let us consider a view which shows Dow Jones and NASDAQ close values over time. To add the measure as dual axis drag the field to the right side of the view and drop it when a black dashed line is seen by the user. The user can also select Dual Axis on the field menu for the measure.

46) What do you know about Page Shelf?

Answer: The Pages shelf is a powerful part of Tableau that allows the user to control the display of output as well as the printed result of that output.

47) What are the new features that have been implemented in Tableau 8.0 regarding the Tableau server performance improvement?

Answer: The following features have been introduced and implemented in Tableau 8.0 which have shown a considerable improvement in performance as compared to Tableau 7.0:

  • Use an extract
  • Limit the dashboard to fully answering only one scenario
  • Limit the data being introduced to each worksheet
  • Remove components that add no value
  • Eliminate any non-essential components from the visualization

48) How can one improve the Tableau Report Performance?

Answer: If a user is not planning on using a set of rows, he/she should filter them out of the data set as early as possible. If the concerned table contains all sales, and the user only wants to look at US sales and create a Custom SQL query that filters it out. If the filter is worksheet dependent, one must try using a Context Filter.

49) What do you mean by Data Blending? When is it used in Tableau?

Answer: Data blending is the process when the user decides to blend data from multiple data sources on a single worksheet. The data is joined on common dimensions. Data Blending does not create row level joins and is not a recommended way to add new dimensions or rows to the concerned data. It is generally used only when we want to fetch data from different sources and make use in single worksheet.

50) What kind of join is used in Data Blending?

Answer: There won’t be any joins as such in Data Blending in Tableau but we have tried to give the column references like primary and foreign key relation.

51) What do you know about a Tableau Server?

Answer: Tableau Server is a business intelligence solution that provides browser-based visual analytics anyone can use at just a fraction of the cost of typical BI software. With just a few clicks, the user can publish or embed live, interactive graphs, dashboards and reports with current data automatically customized to the needs of everyone across the user’s organization. It deploys in minutes and users can produce thousands of reports without the need of IT services — all within the concerned IT infrastructure.

52) Differentiate between Connect Live and Import all data and Import some data.

Answer: The following points can be considered while differentiating between the given:

Connect live – Creates a direct connect to the concerned data values. The speed of the concerned data source will determine performance.

Import all data – Imports the entire data source into Tableau’s fast data engine as an extract. The extract is saved with the workbook.

Import some data – Imports a subset of the concerned data into Tableau’s fast data engine as an extract. This option requires the user to specify what data he/she wants to extract using filters.

53) What does Tableau actually do?

Answer: The primary goal of the developers of Tableau is to help people see and understand data. The software products put the power of data into the hands of everyday people, allowing a broad population of business users to engage with their data, ask questions, solve problems and create value.

54) Who is the stipulated customer of the Tableau software?

Answer: All the software products concerned with Tableau are used by people of diverse skill levels across all kinds of organizations, including Fortune 500 corporations, small and medium-sized businesses, government agencies, universities, research institutions and non-profits. Organizations employ these products in a broad range of use cases such as increasing sales, streamlining operations, improving customer service, managing investments, assessing quality and safety, studying and treating diseases, completing academic research, addressing environmental problems and improving education.

55) When was Tableau founded and by whom?

Answer: Tableau was founded in 2003 by a team comprising Christopher Stolte, Patrick Hanrahan and Christian Chabot.

56) When Tableau was made public and where does the software stock trade?

Answer: Tableau Software is traded on NYSE under the ticker symbol DATA. The company went public on May 17, 2013 at an initial public offering price of $31 per share.

57) Mention the features of the software Tableau.

Answer: Tableau was provided with the given features:

  • Reporting & Dashboard
  • Data Analytics
  • Analytics
  • Business Intelligence
  • Ad Hock Query
  • Data Hierarchy
  • Data Mining
  • Multi-Dimensional Analytics
  • ODBC
  • OLAP
  • Analytics on Share Point, the iPad, Android tablets

58) What are the benefits of using Tableau?

Answer: Using Tableau has the following advantages:

  • Tableau Software is faster than other solutions.
  • Tableau Software is an intuitive, drag-and-drop tool that lets the user see every change as it is being made.
  • With Tableau Software the user can build smart, fit and beautiful dashboards.
  • In Tableau the user can connect directly to databases, cubes, data warehouses, files and spreadsheets.

59) What do you know about Parameters and their working in Tableau?

Answer: Tableau parameters are dynamic variables/values that are used to replace the constant values in data calculations and filters. A user is allowed can create a calculated field value returning true when the score is greater than 80, and otherwise false. Using parameters, one can replace the constant value of 80 and control it dynamically in the formula.

60) What are the differences between parameters and field in Tableau?

Answer: The difference between parameters and fields lies in the application. Parameters allow users to insert their values, which can be integers, float, date, string that can be used in calculations. However, filters receive only values that have been chosen by the users to ‘filter by’ the list, which cannot be used to perform calculations. Users can dynamically change measures and dimensions in parameter but filters do not approve of this feature.

61) What do you know about Quick Filters in Tableau?

Answer: Global quick filters are a way to filter each worksheet on a dashboard until each of them contains a dimension. They are very useful for worksheets using the same data source, which sometimes proves to a disadvantage and generate slow results. Thus, parameters are more useful and are preferred over Quick Filters.

62) What do you know about Aggregation and Disaggregation in Tableau?

Answer: Aggregation and disaggregation in Tableau are the ways to develop a scatterplot to compare and measure data values. As the name suggests, aggregation is the calculated form of a set of values that return a single numeric value. For instance, let us consider a measure with values 1,3,5,7 returns 1. The user can also set a default aggregation for any measure, which is not user-defined. Tableau supports various default aggregations for a measure like Sum, average, Median, Count and others. Disaggregating data refers to viewing each data source row, while analyzing data both independently and dependently.

63) What do you know about Context Filter?

Answer: The concept of a context filter in Tableau makes the process of filtering very smooth and straight forward. It establishes a filtering hierarchy where all other filters present refer to the context filter for their subsequent operations. The other filters now process data that has been passed through the context filter. Creating one or more context filters improves performance as users do not have to create extra filters on large data source, reducing the query-execution time. The user can create a context filter by dragging a filed into ‘Filters’ tab and then, Right-Click that field and select ‘’Add to Context”.

64) Mention the disadvantages of using a Context Filter.

Answer: Tableau takes time to place a filter in context. When a filter is set as context one, the software creates a temporary table for that particular context filter. This table will reload each time and consists of all values that are not filtered by either Context or Custom SQL filter.

65) Differentiate between .twb and .txb.

Answer: The .twb extension is the most common file extension used in Tableau, which presents an XML format file and comprises all the information present in each dashboard and sheet like what fields are used in the views, styles and formatting applied to a sheet and dashboard. But this workbook does not contain any data. The Packaged workbook merges the information in a Tableau workbook with the local data available (which is not on server). The .twbx serves as a zip file, which will include custom images if any.

66) How does a user make use of a Group in a Calculated Field?

Answer: The user can make use of Group in a Calculated Field by adding the same calculation to ‘Group By’ clause in SQL query or by creating a Calculated Field in the Data Window and using that field whenever the user wants to group the fields.

  • Using groups in a calculation. The user cannot reference ad-hoc groups in a calculation.
  • Blend data using groups created in the secondary data source: Only calculated groups can be used in data blending if the group was created in the secondary data source.
  • Use a group in another workbook. The user can easily replicate a group in another workbook by copy and pasting a calculation.

67) How is the “Remove All” option used in the Tableau Auto-Filter Feature?

Answer: The auto-filter provides a feature of removing all the added options by simply clicking the down arrow in the auto-filter heading. The user can scroll down to ‘Customize’ in the dropdown and then uncheck the ‘Show “All” Value’ attribute. It can be activated by checking the field again.

68) How to add Custom Color in Tableau?

Answer: Adding a Custom Color refers to a power tool in Tableau. Restart the Tableau desktop once the .tps file has been saved. From the Measures pane, drag the one to which color has to added to Color. From the color legend menu arrow, select Edit Colors. When a dialog box opens, select the palette drop-down list and customize as per requirement.

69) What do you know about a TDE File in Tableau?

Answer: TDE is a Tableau desktop file that contains a .tde extension. It refers to the file that contains data extracted from external sources like MS Excel, MS Access or CSV file. There are two aspects of TDE design that make them ideal for supporting analytics and data discovery.

  • TDE is a columnar store.
  • They are structured in a unique way which impacts how they are loaded into memory and how they are used by Tableau. This is an important aspect of how TDEs are “architecture aware”. Architecture-awareness means that TDEs use all parts of the computer memory, from RAM to hard disk, and put each part to work what best fits its characteristics.

70) Can a user create Relational Joins in Tableau without creating a New Table?

Answer: Yes, a user can freely create relational joins in Tableau without creating a New Table.

71) What do you mean by ARI in Tableau?

Answer: ARI is the acronym for Assume Referential Integrity. In some cases, the user can improve query performance by selecting the option to Assume Referential Integrity from the Data menu. When the user makes use of this option, Tableau will include the joined table in the query only if it is specifically referenced by fields in the view.

72) What do you know about Default Data Blending Join?

Answer: Data blending is the ability to bring data from multiple data sources into one Tableau view, without the need for any special coding. A default blend is equivalent to a left outer join. However, by switching which data source is primary, or by filtering nulls, it is possible to emulate left, right and inner joins.

73) What do you know about the Drive Program Methodology?

Answer: Tableau Drive is a methodology used for scaling out self-service analytics. Drive is based on best practices for successful enterprise deployments. The methodology relies on iterative, agile methods that are faster and more effective than traditional long-cycle deployment. A cornerstone of this approach is a new model of partnership between business and IT.

74) How good of a software is Tableau for Strategic Acquisition?

Answer: Tableau is an amazing software that can be used for Strategic Acquisition. It gives the user a deep data insight to the extent that other tools can’t. Moreover, it also helps the user to plan and point the anomalies and improvise the entire process for betterment of his/her company.

75) How is performance testing done in Tableau?

Answer: Performance testing is an extremely important part of implementing tableau. This can be done by loading Testing Tableau Server with TabJolt, which is a “Point and Run” load generator created to perform QA. While TabJolt is not supported by tableau directly, it has to be installed using other open source products.

76) What do you know about Dual Axis in Tableau?

Answer: Dual Axis is an excellent phenomenon supported by Tableau that helps users view two scales of two measures in the same graph. Many websites like Indeed.com and other make use of dual axis to show the comparison between two measures and their growth rate in a septic set of years. Dual axes let you compare multiple measures at once, having two independent axes layered on top of one another.

77) Elaborate on the various components of a Dashboard in Tableau.

Answer: The following are the components of any elementary dashboard in Tableau:

  • Horizontal –Horizontal layout containers allow the designer to group worksheets and dashboard components left to right across your page and edit the height of all elements at once.
  • Vertical –Vertical containers allow the user to group worksheets and dashboard components top to bottom down your page and edit the width of all elements at once.
  • Text
  • Image Extract: –A Tableau workbook is in XML format. In order to extracts images, Tableau applies some codes to extract an image which can be stored in XML.
  • Web [URL ACTION]:-A URL action is a hyperlink that points to a Web page, file, or other web-based resource outside of Tableau. The user can use URL actions to link to more information about the concerned data that may be hosted outside of the data source. To make the link relevant to the concerned data, the user can substitute field values of a selection into the URL as parameters.

78) Are parameters allowed to have their own dropdown menus?

Answer: Yes, parameters do have their independent dropdown lists enabling users to view the data entries available in the parameter during its creation.

79) Elaborate on the various products of Tableau.

Answer: These are the various Tableau products:

  1. Tableau Desktop:

It is a self-service business analytics and data visualization that anyone can use. It translates pictures of data into optimized queries. With tableau desktop, the user can directly connect to data from the data warehouse for live up to date data analysis. The user can also perform queries without writing a single line of code. Import all the data into Tableau’s data engine from multiple sources & integrate altogether by combining multiple views in an interactive dashboard.

  1. Tableau Server:

It is more of an enterprise level Tableau software. The user can publish dashboards with Tableau Desktop and share them throughout the organization with web-based Tableau server. It leverages fast databases through live connections.

  1. Tableau Online:

This is a hosted version of Tableau server which helps makes business intelligence faster and easier than before. The user can publish Tableau dashboards with Tableau Desktop and share them with colleagues.

  1. Tableau Reader:

It’s a free desktop application that enables the user to open and view visualizations that are built in Tableau Desktop. He/she can filter, drill down data but cannot edit or perform any kind of interactions.

  1. Tableau Public:

This is a free Tableau software which the user can use to make visualizations with but the user needs to save the workbook or worksheets in the Tableau Server which can be viewed by anyone.

80) Differentiate between Dimensions and Measures.

Answer: Measures are the numeric metrics or measurable quantities of the data, which can be analyzed by dimension table. Measures are stored in a table that contain foreign keys referring uniquely to the associated dimension tables. The table supports data storage at atomic level and thus, allows more number of records to be inserted at one time. For instance, a Sales table can have product key, customer key, promotion key, items sold, referring to a specific event.

Dimensions are the descriptive attribute values for multiple dimensions of each attribute, defining multiple characteristics. A dimension table ,having reference of a product key form the table, can consist of product name, product type, size, color, description, etc.

81) Mention the different connections that can be made by a user using a dataset.

Answer: The user can either connect live to other data set or extract data onto Tableau.

  • Live: Connecting live to a data set leverages its computational processing and storage. New queries will go to the database and will be reflected as new or updated within the data.
  • Extract: An extract will make a static snapshot of the data to be used by Tableau’s data engine. The snapshot of the data can be refreshed on a recurring schedule as a whole or incrementally append data. One way to set up these schedules is via the Tableau server.

The benefit of Tableau extract over live connection is that extract can be used anywhere without any connection and the user can build your own visualization without connecting to database.

82) What do you mean by a hierarchical field?

Answer: A hierarchical field in Tableau is used for drilling down data. It means viewing the data at a more granular level.

83) What do you mean by a Tableau Data Server?

Answer: Tableau server acts as an intermediate between Tableau users and the data. Tableau Data Server allows the user to upload and share data extracts, preserve database connections, as well as reuse calculations and field metadata. This means any changes the user makes to the data-set, calculated fields, parameters, aliases, or definitions, can be saved and shared with others, allowing for a secure, centrally managed and standardized dataset. Additionally, he/she can leverage the server’s resources to run queries on extracts without having to first transfer them to the local machine.

84) What do you know about TDE?

Answer: Tableau Data Engine is one of the most useful features in Tableau. It is an analytical database designed to achieve instant query response, predictive performance, integrate seamlessly into existing data infrastructure and is not limited to load entire data sets into memory. If the user works with a large amount of data, it does takes some time to import, create indexes and sort data but after that everything speeds up. Tableau Data Engine is not really in-memory technology. The data is stored in disk after it is imported and the RAM is hardly utilized.

85) Differentiate between a tree map and a heat map.

Answer: A heat map can be used for comparing categories with color and size. With heat maps, you can compare two different measures together. A tree map also does the same except it is considered a very powerful visualization as it can be used for illustrating hierarchical data and part-to-whole relationships.

86) What do you know about Extracts and Schedules in Tableau?

Answer: Data extracts are the first copies or subdivisions of the actual data from original data sources. The workbooks using data extracts instead of those using live DB connections are faster since the extracted data is imported in Tableau Engine. After this extraction of data, users can publish the workbook, which also publishes the extracts in Tableau Server. However, the workbook and extracts won’t refresh unless users apply a scheduled refresh on the extract. Scheduled Refreshes are the scheduling tasks set for data extract refresh so that they get refreshed automatically while publishing a workbook with data extract. This also removes the burden of republishing the workbook every time the concerned data gets updated.

87) How does one view underlying SQL queries in Tableau?

Answer: Viewing underlying SQL Queries in Tableau can be done in any two ways:

  • Create a Performance Recording to record performance information about the main events you interact with workbook. Users can view the performance metrics in a workbook created by Tableau.
    Help -> Settings and Performance -> Start Performance Recording
    Help -> Setting and Performance -> Stop Performance Recording.
  • Reviewing the Tableau Desktop Logs located at C:\Users\\My Documents\My Tableau Repository. For live connection to data source, the user can check log.txt and tabprotosrv.txt files. For an extract, check tdeserver.txt file.

88) How is performance testing in Tableau?

Answer: Performance testing is an important part of implementing Tableau. This can be done by loading Testing Tableau Server with TabJolt, which is a “Point and Run” load generator created to perform QA. While TabJolt is not supported by tableau directly, it has to be installed using other open source products.

89) What do you mean by a Blended Axis in Tableau?

Answer: In Tableau, measures can share a single axis so that all the marks are shown in a single pane. Instead of adding rows and columns to the view, when the user blends measures there is a single row or column and all of the values for each measure is shown along one continuous axis. We can blend multiple measures by simply dragging one measure or axis and dropping it onto an existing axis.

90) What do you understand by a story in Tableau?

Answer: A story is a sheet that contains a sequence of worksheets or dashboards that work together to convey information. The user can create stories to show how facts are connected, provide context, demonstrate how decisions relate to outcomes, or simply make a compelling case. Each individual sheet in a story is called a story point.

91) Differentiate between discrete and continuous in Tableau.

Answer: There are two types of data roles in Tableau – discrete and continuous dimension.

  • Discrete data roles are values that are counted as distinct and separate and can only take individual values within a range. Examples: number of threads in a sheet, customer name or row ID or State. Discrete values are shown as blue pills on the shelves and blue icons in the data window.
  • Continuous data roles are used to measure continuous data and can take on any value within a finite or infinite interval. Examples: unit price, time and profit or order quantity. Continuous variables behave in a similar way in that they can take on any value. Continuous values are shown as green pills.

92) Mention the steps that need to be followed to create a story in Tableau.

Answer: There are many ways to create a story in Tableau. Each story point can be based on a different view or dashboard, or the entire story can be based on the same visualization, just seen at different stages, with different marks filtered and annotations added. The user can use stories to make a business case or to simply narrate a sequence of events.

  • Click the New Story tab.
  • In the lower-left corner of the screen, choose a size for the story. Choose from one of the predefined sizes, or set a custom size, in pixels.
  • By default, the story gets its title from its sheet name. To edit it, double-click the title. You can also change your title’s font, color, and alignment. Click Apply to view your changes.
  • To start building your story, drag a sheet from the Story tab on the left and drop it into the center of the view
  • Click Add a caption to summarize the story point.
  • To highlight a key takeaway for your viewers, drag a text object over to the story worksheet and type your comment.
  • To further highlight the main idea of this story point, you can change a filter or sort on a field in the view, then save your changes by clicking Update above the navigator box.

93) Differentiate between published data sources and embedded data sources in Tableau.

Answer: The difference between published data source and embedded data source is that,

  • Published data source: It contains connection information that is independent of any workbook and can be used by multiple workbooks.
  • Embedded data source: It contains connection information and is associated with a workbook.

94) What are the different files in Tableau that you are aware of?

Answer: The different Tableau files include:

  • Workbooks: Workbooks hold one or more worksheets and dashboards.
  • Bookmarks: It contains a single worksheet and is an easy way to quickly share the work done by a user.
  • Packaged Workbooks: It contains a workbook along with any supporting local file data and background images.
  • Data Extraction Files: Extract files are a local copy of a subset or entire data source.
  • Data Connection Files: It’s a small XML file with various connection information.

95) How is a view embedded in a Webpage using Tableau?

Answer: Any user can embed interactive Tableau views and dashboards into web pages, blogs, wiki pages, web applications, and intranet portals. Embedded views update as the underlying data changes, or as their workbooks are updated on Tableau Server. Embedded views follow the same licensing and permission restrictions used on Tableau Server. That is, to see a Tableau view that’s embedded in a web page, the person accessing the view must also have an account on Tableau Server.

Alternatively, if an organization uses a core-based license on Tableau Server, a Guest account is available. This allows people in the organization to view and interact with Tableau views embedded in web pages without having to sign in to the server. Contact the server or site administrator to find out if the Guest user is enabled for the site to which the view is going to be published to.

The user can do the following to embed views and adjust their default appearance:

  • Get the embed code provided with a view: The Share button at the top of each view includes embed code that you can copy and paste into your webpage. (The Share button doesn’t appear in embedded views if you change the showShareOptions parameter to false in the code.)
  • Customize the embed code: You can customize the embed code using parameters that control the toolbar, tabs, and more. For more information, see Parameters for Embed Code.
  • Use the Tableau JavaScript API: Web developers can use Tableau JavaScript objects in web applications. To get access to the API, documentation, code examples, and the Tableau developer community, see the Tableau Developer Portal.

96) What do you know about the Tableau Repository?

Answer: Tableau Repository is the centralized part of the Tableau Desktop. It’s the situation wherever the entire info of the desktop are keeping the sort of multiple folders.

97) Mention the various types of dimensions in Tableau.

Answer: The Dimensions are divided into nine different kinds: Slowly ever-changing Dimension, Chop-chop ever-changing Dimension, Unchanged Dimension, Shrunken Dimension, Junk Dimension, Conformed Dimensional, Degenerated Dimension, Role enjoying Dimension, and Inferred Dimension.

  • Slowly ever-changing Dimension:

If the information within the dimension is ever-changing over an amount of your time then such reasonable dimension is thought as Slowly ever-changing Dimension.

  • Chop-chop ever-changing Dimension:

If the information within the dimension is ever-changing chop-chop (or) of times there such a sort of dimension is thought of as Rapidly ever-changing Dimension.

  • Unchanged Dimension:

If the information within the dimension is unchanged or the values within the Unchanged Dimension is constant. So, it’s referred to as Static Dimension.

  • Shrunken Dimension:

The set of 1 dimension is thought as Shrunken Dimension.

  • Junk Dimension:

Junk suggests that unwanted or Unrelated. If the dimension containing the unrelated info, then it’s referred to as Junk Dimension.

  • Conformed Dimension:

If one dimension is usually shared by the multiple business areas then such a reasonably dimension is thought as Conformed Dimension.

  • Degenerated Dimension:

The dimension that contains solely primary keys with none matter info is thought as Degenerated Dimension.

  • Role enjoying Dimension:

If one dimension is enjoying multiple roles within the truth table or if one dimension secret is hooked up to multiple foreign keys within the truth then such a sort of dimension is thought as “Role enjoying Dimension”.

  • Inferred Dimension:

The empty dimension is called “Inferred Dimension”. It’s usually employed in ETL. As the Inferred Dimension doesn’t contain its own primary keys, we are going to produce the synthetic primary keys called “Surrogate Keys

98) What are the different measure in Tableau?

Answer: The following types of measure exist in Tableau:

Additive Measure: If the live is supporting the aggregate with all the size then such reasonably live is thought as “Additive Measure”.

Semi-Additive Measure: If the live is supporting the aggregations solely on few of dimensions however not all of them such reasonably live is thought as semi-Additive live.

Non-Additive Measure: If the live isn’t giving the United States any long outputs when applying the aggregations with the list of all dimensions then it’s called “Non-Additive Measure”

99) What do you know about Truth Tables in Tableau?

Answer: There are three types of truth tables in Tableau:

Cumulative truth Table:

If the truth/the very fact/the actual fact table is containing solely the additive facts these such a sort of fact table is thought as Cumulative truth Table. It contains the periodic info like year wise total sales, state wise average revenues, etc.

Snapshot truth Table:

If the truth/the very fact/the actual fact table containing solely semi-additive & non-additive facts then such a sort of fact table is thought of as Snapshot truth Table. It contains instant info like day wise discounts, week wise margins etc.

Factless truth Table:

If the truth/the very fact/the actual fact table is containing solely the keys with none facts such a sort of fact tables are thought as truthless Fact Table or Factless Truth Table.

100) What do you mean by a workbook in Tableau?

Answer: In Tableau, workbook files are abundant similar to MS-Excel workbooks. The book is that the instrumentation for all add the Tableau. To create a replacement book click on file new. The workbook contains:

  1. Data section
  2. Tableau space

 

Conclusion: 

Tableau is one of most preferred interactive data visualization products focused on business intelligence. As there is more and more focus on data analytics, the demand only going to increase for data visualization tools as well to make critical decisions. 100 Top Tableau interview questions given above will help all job seekers to prepare better for the interviews.

 

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