1. What are the different data types supported by Tableau?
- Text values such as strings.
- Date values.
- Date and time values.
- Numerical values.
- Boolean values of relational data.
- Geographical values which are used with maps.
2. What are Measures and Dimensions?
- These are the numeric metrics or measurable quantities of the data, it cannot be analyzed by a dimension table.
- Measures are stored in a table that contains foreign keys which refer uniquely to the associated dimension tables.
- The table supports data storage at the atomic level and hence it allows more number of records to be inserted at one time.
Example: A sales table can have a product key, customer key, promotion key, items sold, which refers to a specific event.
- These are the descriptive attribute values for multiple dimensions of each attribute that define multiple characteristics.
- A dimension table, having reference to a product key form the table, can consist of product name, product type, size, colour, description, etc.
3. What is the difference between .twb and .twbx extension?
A “.twb” is an XML document which contains all the selections and layout which are made in your Tableau workbook. It does not contain any data.
A “.twbx” is a zipped archive that contains a “.twb” and any external files such as extracts and background images.
4. What is the difference between Tableau Worksheet, Dashboard, Story, and Workbook?
Tableau Worksheet: Tableau uses a workbook and sheet file structure which is much similar to Microsoft Excel.
Workbook: A workbook contains sheets, which can be a worksheet, dashboard, or a story. It contains a single view along with shelves, legends, and the Data pane.
Dashboard: It is a collection of views from multiple worksheets.
Story: It contains a sequence of worksheets or dashboards that work together to convey information.
5. What are the different connections you can make with your dataset?
Ans: You could connect to live to the data set or extract data into Tableau.
- Connecting live to a data set leverages its computational processing and storage.
- New queries will be passed to the database and will be reflected as new or updated within the data.
- 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 through the Tableau server.
The benefit of Tableau extract over a live connection is that extract can be used anywhere without any connection and you can build your own visualization without connecting to the database.
6. What are the Filters? Name the Different Filters in Tableau.
Ans: Filters in Tableau is a way of restricting the content of the data that may enter a Tableau workbook, dashboard, or view. The different types of Tableau Filters are.
- Extract filters.
- Context filters.
- Data source filters.
- Filters on measures.
- Filters on dimensions.
- Table calculation filter.
7. What are Extracts and Schedules in Tableau server?
- 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 data extraction, 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.
8. What are Treemaps?
Ans: A treemap is used for representing the hierarchical data. The space in the view is divided into rectangles that are sized and ordered by a measure. There are two measures that are distinguished in Treemaps.
- Scenario: Displays sales and profit in all regions for different product categories and sub-categories.
- Analysis: The larger the size of the node, the higher the profit in that category. Similarly, the darker the node, the more sales in that category.
Apply the following steps to test the scenarios.
- Select two dimensions “Category” and “Sub-Category”.
- Select two measures “Sales” and “Profit” from the data pane.
- Use the Show-me tool and then select tree-map.
9. What are Heat maps?
Ans: A heap map is used for comparing the categories by applying the colour and size. These are two measures that are also distinguished in Heat maps.
- Scenario: Displays the sales and profit in all regions for different product categories and sub-categories.
- Analysis: Profit is represented by colour and ranges from orange for loss to blue for profit. The total sales are represented by size.
A heat map is not only defined by colour, but you can also use its size. Apply the following steps to test the scenarios.
- Drag Region field to Columns shelf, and Category and Sub-Category fields in Rows shelf.
- Use the ShowMe tool and select the Heat Map.
- Observe the hotter and colder regions in the heat map that is produced.
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10. Name the components of a Tableau Dashboard.
Ans: Tableau Dashboard comprises these five components.
- Horizontal: The horizontal layout container allows the designer to group worksheets and dashboard components from left to right across the page and edits all the elements of height at once.
- Vertical: The vertical containers allow the user to group worksheets and dashboard components from top to bottom down your page and edit the width of all elements at once.
- Text: This involves all textual fields.
- Image Extract: This component is used for extracting the images in Tableau. A Tableau workbook is in XML format. In order to extract 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 resources outside of a Tableau.
- The URL actions are used to link for more information about your data that may be hosted outside of your data source.
- To make the link relevant to your data, you can substitute field values of a selection into the URL as parameters.
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11. What are Dimensions and Facts?
- Dimensions are nothing but the descriptive text columns.
Example: product name, city, etc.
- Facts are the measures that include numerical values.
Example: sales, profit, etc.
12. How Can You Optimize the Performance of a Dashboard?
Ans: The performance of a dashboard can be optimized in multiple ways.
- Maximize the number of fields and records. You can exclude the unused fields from your visualization or use the extract filters.
- Limit the number of filters that are used by avoiding quick filters and use the action and parameter filters rather. These filters reduce query loads.
- Use Min/Max instead of Average because average functions require more processing time than Min/Max.
- Use boolean or numerical calculations more than string calculations. Computers process integers and boolean types much faster than strings.
Boolean > int > float > date-time > string
13. Which visualization will be used in the given Scenarios? To show aggregated sales totals across a range of product categories and subcategories. To show the duration of events or activities. To show quarter wise profit growth.
Ans: The following visualisations are used for the given scenarios.
- Gantt chart
- Waterfall chart
14. How can you schedule a workbook in Tableau after publishing It?
- After signing in to Tableau Server, navigate to Content -> data sources or Content -> Workbooks, depending on the type of content which you want to refresh.
- Select the checkbox for the data source or workbook which you want to refresh, and then select Actions -> Extract Refresh.
- In the Refresh Extracts dialogue, select Schedule a Refresh, and complete the following steps:
- Select the schedule you want.
- If available, specify whether you want a full or incremental refresh.
15. What is the blended axis?
- It is the place where multiple measures are displayed over a single axis and all the marks are displayed in a single pane.
- You can blend multiple measures by simply dragging one measure or axis and dropping it onto an existing axis.
- Follow the below steps for applying the blending measures.
- Drag a dimension in a column.
- Drag the first measure in the column.
- Drag the second measure in the existing axis.
16. How to create filled maps?
Ans: Filled maps are created by implementing the following steps.
- Build a Map View and then double-click on a geographic field such as State, Area Code, Zip Code, etc.
- Select the Filled Map Mark Type. The Automatic mark type will then display this type of view as circles over a map. On the Marks card, select Filled Map to colour the geographic areas.
- Drag a field to the Color shelf, define how the locations are coloured by dragging another field to the Color shelf.
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17. What are the products offered by Tableau? Explain a few things about them.
Ans: Tableau mainly consists of four products.
- Tableau Prep: It is responsible for preparing data for analysis. This tool provides three coordinated views that provide a complete picture of data.
- Tableau Desktop: It is a container where the analysis takes place. It has a powerful drag and drops analytics which is very easy to use. Through the desktop, you get your data insights quickly.
- Tableau Online: It is a secure and scalable self-service analytics cloud tool. It can be used anywhere, anytime. It has eliminated the complexities of IT.
- Tableau Server: It is used for fulfilling the BI requirements from small to large scale enterprises. It provides an on-premise solution. This tool can take data from anywhere and is shared across the organization through desktop or mobile browsers.
18. What is the difference between Traditional BI Tools and Tableau?
- The architecture of BI has hardware limitations.
- It doesn’t support in-memory, multi-thread, and multi-core computing.
- It has a predefined view of data.
- It requires a sound knowledge of BI and skills.
- It provides data security.
- It will not have any dependencies.
- When advanced technologies are used then tableau supports the memory.
- It applies the predictive analysis for various business operations.
- It is easy to work and easily understandable without having any knowledge of BI and skills.
- It provides data security for the professional version but not for the public.
19. How to create a calculated field in Tableau?
Ans: The following steps are applied to create a calculated field.
- Select Analysis -> in the dropdown -> Select create calculated field.
- Calculation Editor Box will open, give the name to the calculated field.
- Enter a formula in the calculation editor.
Example: Sum(Profits)/Sum(Sales). (Calculation Editor validates the formula)
- Click, Ok.
Now, the new calculated field will be added to the data pane.
20. How to create stories in Tableau?
Ans: In a Tableau, the stories can be created in many ways. Each story point is based on a different view or dashboard. The entire story can be based on the same visualization applied at different stages, with different marks filtered and annotations added. You can use stories for making a business case or for narrating a sequence of events.
The following steps are applied for creating the stories in Tableau.
- Click the New Story tab.
- In the lower-left corner of the screen, choose a size for your story. In the predefined sizes, choose one from them, or set a custom size, in pixels.
- By default, your story gets its title from its sheet name. For editing, double-click the title. You can also change your title’s font, colour, 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 centre of the view.
- Click on 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.
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21. Define shelves and sets?
- Each worksheet in Tableau has the shelves such as columns, rows, marks, filters, pages and more.
- You can build your own visualization structure by placing filters on shelves. The marks can be controlled by including or excluding data.
- The sets that are used for computing a condition on which the dataset is prepared. The data are grouped together based on a condition.
- The Fields which are responsible for grouping are called sets.
- Example: students having grades more than 70%.
22. Differentiate parameters and filters in Tableau.
- These are a very simple and straightforward feature in Tableau. Filters apply to dimension or measures directly.
Example: To display only Uttar Pradesh or Kerala in a State dimension, you can apply the filter on that.
- Multiple UI options are available in tableau. The UI options include filters like radio buttons, drop-down lists, checkboxes, sliders, and more.
- Tableau also contains the Filters on sheets.
- These are similar to variables. Parameters are complex and more powerful. Like a variable, a parameter can also be used in calculations. It allows only a single value.
- It has the same UI options except for checkboxes because checkboxes don’t have a single value.
Example: You can create a parameter for interest rate and period, and then we can use these parameters to calculate interest and principal payments.
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23. Can we create cascading filters without using context filters?
Ans: Cascading filters means filter2 values are dependent on filter1 value.
Example: filter1 is country and if we select “India” for filter1, filter2 values should display all Indian states. This feature is achieved by using the option “Only Relevant Values”.
24. What are the challenges faced when working with huge volumes of data?
Ans: The challenges include.
- View running will be slow.
- Data Extraction.
- Alignment issues with data.
- Testing Data.
25. What is a dual-axis?
Ans: Dual Axis helps users to view two scales of two measures in the same graph. Many websites like Indeed.com and others make use of dual-axis to display the comparison between two measures and their growth rate over a set of years. Dual axes let you compare multiple measures at once, having two independent axes layered on top of one another.
26. What are the different Tableau files?
Ans: Different Tableau files include.
- Workbooks: It holds one or more worksheets and dashboards.
- Bookmarks: It contains a single worksheet and it is very easy to share your work quickly.
- Packaged Workbooks: It contains a workbook along with supporting local file data and background images.
- Data Extraction Files: The extraction files are a local copy of a subset or entire data source.
- Data Connection Files: The connection file is a small XML file that contains various connection information.
27. What Are the Different Joins in Tableau?
Ans: Joining is a method of combining related data by using a common key. There are five different joins available in Tableau.
- Inner Join: The result of a table contains values that have matches in both tables.
- Left Join: The result of a table contains all values from the left table and corresponding matches from the right table.
- Right Join: The result of a table contains all values from the right table and the corresponding matches from the left table.
- Outer Join: The result of a table contains all values from both tables.
- Union Join: It is another method of combining two or more tables by appending rows of data from one table to another.
28. What is the difference between discrete and continuous in Tableau?
- Discrete data roles consist of separate and distinct values. Its roles can take individual values within a range.
Example: No. of threads in a sheet, cancer patients in the hospital, state.
- The discrete values are displayed as blue icons in the data window and blue pills on shelves.
- The discrete fields can be sorted.
- Continuous data roles consist of any value within a finite or infinite interval.
Example: age, unit price, order quantity.
- The continuous values are displayed as green icons in the data window and green pills on shelves.
- The continuous fields cannot be sorted.
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29. How to view a SQL generated by Tableau Desktop?
Ans: Tableau Desktop Log files are located in the “C:\Users\My Documents\My Tableau\” repository. If you have a live connection to the data source, you have to check the “log.txt” and “tabprotosrv.txt” files. If you are using Extract, then you have to check the “tdeserver.txt” file. The “tabprotosrv.txt” file often shows detailed information about queries.
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30. What is disaggregation and aggregation of data in Tableau?
Aggregation: The process of summarizing the data and viewing a single numeric value is called aggregation.
Example: sum/avg of salary for each employee.
Disaggregation: The process of viewing each transaction to analyze all the measures both dependently and independently.
Example: Individual salary transactions for each employee.
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