Tableau Interview Questions | Eklavya Online

Tableau Interview Questions

Tableau expresses fields and assigns data types automatically. If the data source appoints the data type, Tableau will use that data type. If the data source doesn’t individually assign a data type, Tableau will assign one. Tableau consist of the following data types:

  • Date values
  • Text values
  • Numerical values
  • Date and time values
  • Boolean values (True or False conditions)
  • Geographic values (longitude and latitude used for maps)

Tableau server acts as a middle man between the data and Tableau uses. Tableau Data Server allows you to share and upload data extracts, preserve database connections, as well as reuse calculations and field metadata.

This means any changes you can make for the calculated field, data-set, aliases, definitions or parameters, can be saved and shared with others, that allows for a secure, centrally managed and standardized dataset as well as you can leverage your server’s resources to run queries on extracts without having first to transfer them to your local machine.

Tableau is not restricted by the number of rows in the table. Tableau is used to access petabytes of data because it only retrieves the rows and columns.

Yes, Tableau Desktop can be installed on Mac as well as window operating system.

In Tableau, you can join an atmost 32 tables.

Tableau Data Engine is a cool feature in Tableau. It?s an analytical database that designed to achieve instant query response, predictive performance, integrate seamlessly into existing data infrastructure, and it is not limited to load entire data sets into the memory.

If you are work with a large amount of data, it does take some time to create indexes, import, and sort data, but after that everything speeds up. Tableau Data Engine is not in-memory technology. The data is stored in disk after its import, and the RAM is hardly utilized.

  • ableau is a powerful data visualization tool used in the business intelligence industry.
  • It simplifies the raw data into a very easily understandable format.
  • It visualizes and creates interactive, sharable dashboards.
  • Tableau is not required any technical or programming skills.

Yes, Tableau software is suitable for strategic acquisition because it gives data insight to the extent that other tools can’t.

We can connect the datasets in two ways, such as:

Live: Live connection sends queries to your database and retrieves data. These queries will return whatever data is currently in the database.
Extract: Extracts connection saved subsets of data that use to improve performance or to take the advantages of Tableau functionality which are not supported or available in your original data.

  • Click on the drop-down option to the right of dimension on the data pane and go to the create options and select the calculated field to open the calculation editor.
  • Name the calculated field and create a formula.

There are three main features of Tableau, such as:

Data Blending: Data blending is an essential feature in Tableau. It is used when we combine related data from multiple data sources, which you want to analyze together in a single view, and represent in the form of a graph.
Real-time Analysis: Real-Time Analysis makes users able to quickly understand and analyze dynamic data when the Velocity is high, and real-time analysis of data is complicated. Tableau can help extract valuable information from fast-moving data with interactive analytics.
The Collaboration of Data: Data analysis is not isolating task. That’s why Tableau is built for collaboration. Team members can share data, make follow up queries, and forward easy-to-digest visualizations to others who could gain value from the data. Making sure everyone understands the data and can make informed decisions is critical to success.

Yes, we can place an excel file in a shared location, but for better performance, we should use extract.

In Tableau, sets are used to create subsets of data based on the specific condition defined by the user. Sets are only created based on the dimension field.

There are two types of sets in Tableau, such as:

Dynamic Sets: The values or members in the dynamic sets get change when the underlying data changes.
Fixed Sets: The values or members in the fixed sets does not change when the underlying data changes.

The dual-axis is used to visualize two different measures in two different chart types. A date column and two measures are necessary to build a dual-axis chart.

Tableau Desktop: Tableau Desktop establish connectivity between the Data Warehouse and other various types of files. The dashboards and the workbooks created here can be either shared locally or publicly. It allows us to code and customizes reports. Right from establishing the stories, charts to blending them all to form a dashboard, all the necessary work is created in Tableau Desktop.
Tableau Public: This Tableau version is specially built for cost-effective users. The word ‘Public’ means that the created workbooks cannot be saved locally. They should be kept on the Tableau’s public cloud, which can be accessed and viewed by anyone.
Tableau Online: Its functionality is similar to the Tableau server, but data is stored on the server that hosted on the cloud, which is maintained by the Tableau group. There is no storage limit on the data which is published in the Tableau Online. Tableau Online creates a direct link over 40 data sources who are hosted in the cloud such as the Hive, MySQL, Spark SQL, Amazon Aurora, and many more.
Tableau Server: The software is correctly used to share the workbooks, visualizations, which is created in the Tableau Desktop application over the organization. To share dashboards in the Tableau Server, you should first publish your workbook in the Tableau Desktop. Once the workbook has been uploaded to the server, it will be accessible only to the authorized users.
Tableau Reader: Tableau Reader is a free tool which allows us to view the visualizations and workbooks, which is created using Tableau Desktop or Tableau Public. The data can be filtered, but modifications and editing are restricted. There is no security in Tableau Reader as anyone can view workbook using Tableau Reader.

If Tableau Desktop license expires today, then you cannot access the dashboard or worksheet because the username on the server will have to unroll unlicensed.

But others can access because the site admin can change the ownership to another person, so the extracts do not fail.

A group is a combination of the members of the dimension which make higher-level categories.

TDE is a Tableau desktop file which contains a .tde extension. It refers to the file to include data extracted from external sources like MS Access or CSV file, MS excel.

There are two aspects of TDE file that make them ideal for supporting analytics and data discovery.

  • TDE is a columnar store.
  • TDE uses all parts of the computer memory from RAM to the hard disk and puts each piece to work what is the best for its characteristics.

There are several types of data terminologies in Tableau, such as:

Bookmark: A .tbm document in the bookmarks folder in the Tableau repository that contains a single worksheet. It helps in improving data analysis. Unlike, web browser bookmarks, .tbm files are a compatible way to display various studies quickly.
Workbook: A workbook is a file with .twb extension that holds one or more worksheets as well as dashboards and stories.
Dashboard: The dashboard is a combination of several views that are arranged on a single page. In Tableau, dashboards are used to observe and compare a variety of data together, and also it allows interacting with other worksheets.
Data Source Page: Data Source is a page where you can set up your data source. Does this data source page generally consist of four main areas? Join area, left pane, a preview area, and metadata area.
Worksheet: The worksheet is a collection of sheets. It’s a place where you build views of your data by dragging various fields onto the shelves.
Dimensions: Dimension is commonly known as a field of categorical data. Dimensions hold discrete data such as members and hierarchies that cannot be aggregated. It also contains characteristic values such as dates, names, and geographical data. The dimensions used to reveal details of your information.
Measures: measures are the measurable quantities of the data, which can be analyzed by a dimension table. Measures are stored in a table which contains foreign keys referring uniquely to the associated dimension tables. The table supports data storage at the atomic level and thus, allows the number of records to be inserted at one time.
For example, a Sales table can have a product key, customer key, promotion key, items sold, referring to a specific event.
Filters shelf: Filter shelf is located on the left side of the workbook. Filters shelf is used to exclude the data from a view by filtering it using both dimensions and measures.
Pages shelf: Page shelf is on the left side of the view. With the help of the page shelf, you can split a view into a sequence of pages based on the values and members in a continuous or discrete field. Adding a field with the pages shelf is similar to adding a field in rows shelf. For each new row, a new page is created.
Marks card: Marks card is on the left side of the worksheet. The user can drag fields to the control mark properties such as color, type, shape, size, label, detail, and tooltip.

Bookmarks: It contains only single worksheet and its easy way to share your work.
Workbooks: Workbook can hold one or more dashboards and worksheets.
Packaged workbooks: It contains the workbook along with any supporting local file data and background images.
Data extraction files: Data extraction files are a local copy of a data source or a subset.
Data connection files: Data connection file is a small XML file that contain various connection information.

In Tableau a hierarchical field is used for drilling down data. It means viewing your data at a more granular level.

A story is a sheet which contains a sequence of dashboards or worksheets that work together to deliver information.

You can create stories to show how the facts are connected, provide context, and demonstrate how decisions relate to outcomes or make a compelling case. Each sheet in a story is known as a story point.