Question 1 : What is data visualization?
Answer : Data visualization refers to the techniques used to organize and present information intuitively (e.g. points, lines, or bars). According to Tableau, using Tableau visualizations, you gain the ability to quickly answer questions; your data becomes a competitive advantage instead of an underutilized asset.
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Question 2 : Name the file extensions in Tableau.
Answer : There are many file types and extensions in Tableau, some of them are:
- Tableau Workbook (.twb)
- Tableau Packaged Workbook (.twbx)
- Tableau Data Source (.tds)
- Tableau Packaged Datasource (.tdsx)
- Tableau Data extract (.tde)
- Tableau Bookmark (.tdm)
- Tableau Map Source (.tms)
- Tableau Preferences (.tps)
Question 3 : How do we test in Tableau?
Answer : You can do performance testing on Tableau with Tableau Server load-testing solution called “Tab Jolt”. You can use Tab Jolt to push a heavy workload onto Tableau Server to give it a jolt and study how the server bends or breaks under load.
Question 4 : What is the difference between Quick Filter, Normal filter, and Context filter?
Answer : In Tableau, filters are used to restrict the data from the database. The differences between Quick Filter, Normal Filter, and Context Filter are:
- A normal Filter is used to restrict the data from a database based on the selected dimension or measure. A Traditional Filter can be created by simply dragging a field onto the ‘Filters’ shelf.
- A quick filter is used to view the filtering options and filter each worksheet on a dashboard while changing the values dynamically (within the range defined) during the run time.
- Context Filter is used to filtering the data that is transferred to each worksheet. When a worksheet queries the 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.
Question 5 : What is referential integrity?
Answer : Referential integrity is a concept that ensures that relationships between databases/tables remain consistent, i.e. it ensures that the references to data are valid. You can improve query performance by selecting this option from the Data menu. When you use this option, Tableau will include the joined table in the query only if it is specifically referenced by fields in the view.
Question 6 : What is default Data Blending Join?
Answer : Data blending Join 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.
Question 7 : How do you add custom colors to Tableau?
Answer : Tableau offers three types of color palettes: categorical, sequential, and diverging. You can create your custom color palette by modifying the Preferences.tps file that comes with Tableau Desktop. The Preferences.tps file is located in the My Tableau Repository. The preferences file is a basic XML file that you can open in a text editor to modify. In tableau 9.0 version there is a color picker option.
Question 8 : How do you automate reports using Tableau software?
Answer : This is how you can automate the reports: while publishing the report to the Tableau server, you will find the option to schedule reports. Click on this to select the time when you want to refresh the data.
Question 9 : What are the platforms Tableau server can run on?
Answer : Tableau server can run on Windows and Mac.
Question 10 : Explain and show how to implement the serialization of a binary tree.
Answer : You can write serialization for leaf nodes, and then for parent nodes.
Recursive map: {value: [serialize(left), serialize(right)]}, where serialized leaf is null.
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Question 11 : What is Tableau?
Answer : Tableau is a business intelligence software.
It allows anyone to connect to the respective data.
Visualizes and creates interactive, shareable dashboards.
Question 12 : How many maximum tables can you join in Tableau?
Answer : You can join a maximum of 32 tables in Tableau.
Question 13 : What is the difference between Traditional BI Tools and Tableau?
Answer :
| Traditional BI Tools | Tableau |
| 1. Architecture has hardware limitations. | 1. Do not have dependencies. |
| 2. Based on a complex set of technologies. | 2. Based on Associative Search which makes it dynamic and fast |
| 3. Do not support in-memory, multi-thread, multi-core computing. | 3. Supports in memory when used with advanced technologies. |
| 4. Has a predefined view of data. | 4. Uses predictive analysis for various business operations. |
Question 14 : What are Measures and Dimensions?
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.
Question 15 : What are sets?
Answer : Sets are custom fields that define a subset of data based on some conditions. A set can be based on a computed condition, for example, a set may contain customers with sales over a certain threshold. Computed sets update as your data changes. Alternatively, a set can be based on the specific data point in your view.
Question 16 : What is the difference between .twb and .twbx extension?
Answer :
- A .twb is an XML document which contains all the selections and layout made you have made in your Tableau workbook. It does not contain any data.
- A .twbx is a ‘zipped’ archive containing a .twb and any external files such as extracts and background images.
Question 17 : What is a hierarchical field?
Answer : A hierarchical field in tableau is used for drilling down data. It means viewing your data in a more granular level.
Question 18 : What is Tableau Data Engine?
Answer : Tableau Data Engine is a really cool feature in Tableau. Its 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 you work 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.
Question 19 : What is Tableau Data Server?
Answer : Tableau server acts a middleman between Tableau users and the data. Tableau Data Server allows you to upload and share data extracts, preserve database connections, as well as reuse calculations and field metadata. This means any changes you make 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, you can leverage your server’s resources to run queries on extracts without having to first transfer them to your local machine.
Question 20 : What are the different filters in Tableau and how are they different from each other?
Answer : In Tableau, filters are used to restrict the data from database.
The different filters in Tableau are: Quick , Context and Normal/Traditional filter are:
- Normal Filter is used to restrict the data from database based on selected dimension or measure. A Traditional Filter can be created by simply dragging a field onto the ‘Filters’ shelf.
- Quick filter is used to view the filtering options and filter each worksheet on a dashboard while changing the values dynamically (within the range defined) during the runtime.
- Context Filter is used to filter the data that is transferred to each individual worksheet. When a worksheet queries the 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.
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Question 21 : What are groups?
Answer : A group is a combination of dimension members that make higher level categories. For example, if you are working with a view that shows average test scores by major, you may want to group certain majors together to create major categories.
Question 22 : What is the difference between joining and blending in Tableau?
Answer :
- Joining term is used when you are combining data from the same source, for example, worksheet in an Excel file or tables in the Oracle database
- While blending requires two completely defined data sources in your report.
Question 23 : How to do Performance Testing in Tableau?
Answer : Performance testing is again 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.
Question 24 : How to remove ‘All’ options from a Tableau auto-filter?
Answer : The auto-filter provides a feature of removing ‘All’ options by simply clicking the down arrow in the auto-filter heading. You 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.
Question 25 : What are Extracts and Schedules in Tableau server?
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 extraction. This also removes the burden of republishing the workbook every time the concerned data gets updated.
Question 26 : How to add Custom Color to Tableau?
Answer : Adding a Custom Color refers to a power tool in Tableau. Restart you Tableau desktop once you save .tps file. From the Measures pane, drag the one you want to add color 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.
Question 27 : How to automate reports?
Answer : You need to publish report to tableau server while publishing you will find one option to schedule reports. You just need to select the time when you want to refresh data.
Question 28 : What is story in Tableau?
Answer : A story is a sheet that contains a sequence of worksheets or dashboards that work together to convey information. You 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.
Question 29 : Mention what are different Tableau files?
Answer : Different Tableau files include:
- Workbooks: Workbooks hold one or more worksheets and dashboards
- Bookmarks: It contains a single worksheet and its an easy way to quickly share your work
- 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
Question 30 : Is Tableau software good for strategic acquisition?
Answer : Yes! For sure. It gives you data insight to the extent that other tools can’t. Moreover, it also helps you to plan and point the anomalies and improvise your process for betterment of your company.
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Question 31 : What do you understand by blended axis?
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 you blend 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.
Question 32 : Mention what is the difference between published data sources and embedded data sources in Tableau?
Answer : The difference between the 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.