Tableau Interview Questions & Answers – Updated 2020
Question 1
Define the different type of Tableau Products?
Answer
Tableau Reader:
Tableau Desktop is a place where the visualizations are built and we can open and view them with this free desktop application. It is read-only, so we cannot perform any other interactive tasks and edit them but we can drill down the data and filter it.
Tableau Server:
This Tableau software is mostly used at the enterprise level. The web-based Tableau server shares throughout the organization the dashboards that are published with Tableau Desktop. The fast databases can be leveraged through its live connections.Tableau Public:
We can easily construct the visualizations with this free Tableau software, but as it belongs the public, we are required to save the worksheets or the workbook in the Tableau Server to be accessed by anyone.
Tableau Reader:
Tableau Desktop is a place where the visualizations are built and we can open and view them with this free desktop application. It is read-only, so we cannot perform any other interactive tasks and edit them but we can drill down the data and filter it.
Tableau Server:
This Tableau software is mostly used at the enterprise level. The web-based Tableau server shares throughout the organization the dashboards that are published with Tableau Desktop. The fast databases can be leveraged through its live connections.Tableau Public:
We can easily construct the visualizations with this free Tableau software, but as it belongs the public, we are required to save the worksheets or the workbook in the Tableau Server to be accessed by anyone.
Question 2
Define Dimensions and Measures in Tableau?
Answer : Dimensions: it defines the multiple characteristics, and for the each attribute’s multiple dimensions they are the descriptive attribute values. A dimension table is comprised of product type, description, product name, color, and size since it has the reference of a product key form the table.
Measures:
Measures can be analyzed by the dimension table and they are the measurable quantities or the numeric metrics of the data. The table that contains the measures is consist of the foreign keys and they distinctly refer the associated dimension tables. Multiple numbers of records can be inserted in a single instance because of the support of the table to store the data at the atomic level. For example, customer key, product key, items sold, and promotion key and many more can be in a sales table and refers to a specific event.
Measures:
Measures can be analyzed by the dimension table and they are the measurable quantities or the numeric metrics of the data. The table that contains the measures is consist of the foreign keys and they distinctly refer the associated dimension tables. Multiple numbers of records can be inserted in a single instance because of the support of the table to store the data at the atomic level. For example, customer key, product key, items sold, and promotion key and many more can be in a sales table and refers to a specific event.
Question 3
Explain the different types of connections made with the dataset?
Answer : We can either extract the data onto Tableau or connect live to the dataset.
Extract: The data can be made as a static snapshot with an extract and is used as the data engine of Tableau. And on a recurring schedule, the snapshot of the data is refreshed or it can increasingly append the data and the Tableau server is very useful to set up these schedules. Even without any connection, we can use the extract and any of our own visualizations can be built without any connection to the database. This is the major advantage of Tableau extract over the live connection.Live: the computational storage and processing can be leveraged by connecting live to a dataset. And the database will have the new queries and it will be displayed as updated or new within the data.
Extract: The data can be made as a static snapshot with an extract and is used as the data engine of Tableau. And on a recurring schedule, the snapshot of the data is refreshed or it can increasingly append the data and the Tableau server is very useful to set up these schedules. Even without any connection, we can use the extract and any of our own visualizations can be built without any connection to the database. This is the major advantage of Tableau extract over the live connection.Live: the computational storage and processing can be leveraged by connecting live to a dataset. And the database will have the new queries and it will be displayed as updated or new within the data.
Question 4
Describe Tableau Desktop?
Answer : Tableau Desktop is a data visualization and a self-service business analytics by which the pictures of the data can be translated into the optimized queries. The data can be connected directly to the to the data analysis from the data warehouse, supported by the tableau desktop. The queries can be performed without having to write a single line of code. By combining multiple views in an interactive dashboard, all the data can be imported from the multiple sources into the data engine of Tableau and be integrated all together.
Question 5
Explain Tableau Data Server?
Answer : We can share and upload the data extracts, field the metadata, reuse the calculations, and preserve the database connections with the Tableau Data Server and it serves as the mediator between the data and the Tableau users. A secure, standardized, and centrally managed dataset can be established by saving and sharing with others any changes made to the parameters, dataset, definitions, aliases, and calculated fields.
The resources of the servers can be leveraged and they do not have to be transferred to the local machine first and it can be used to run queries on extracts.
The resources of the servers can be leveraged and they do not have to be transferred to the local machine first and it can be used to run queries on extracts.
Question 6
Explain and distinguish the filters in Tableau?
Answer : The restriction of the data from the database is accomplished by using the filters.
There are three different types of filters are used in Tableau:
Context
Quick
Normal/Traditional
The data that can be transferred to each individual worksheet is filtered by the Context Filter. A worksheet creates a temporary flat table when it queries the data source. And to compute the chart this flat table is used. The values that are not filtered out by either the Context Filter or the Custom SQL are included by this temporary table.
To filter each worksheet on a dashboard and to view the filtering options Quick filter is used. The dashboard worksheet can even be filtered dynamic changes of the values during the runtime.
A Normal Filter works on the basis of the selected measure and dimension so as to restrict the data from the database. Just by dragging a field onto the ‘Filters’ shelf we can create a Traditional Filter.
There are three different types of filters are used in Tableau:
Context
Quick
Normal/Traditional
The data that can be transferred to each individual worksheet is filtered by the Context Filter. A worksheet creates a temporary flat table when it queries the data source. And to compute the chart this flat table is used. The values that are not filtered out by either the Context Filter or the Custom SQL are included by this temporary table.
To filter each worksheet on a dashboard and to view the filtering options Quick filter is used. The dashboard worksheet can even be filtered dynamic changes of the values during the runtime.
A Normal Filter works on the basis of the selected measure and dimension so as to restrict the data from the database. Just by dragging a field onto the ‘Filters’ shelf we can create a Traditional Filter.
Question 7
How aggregation of data works in Tableau?
Answer : Aggregation is a process in which we measure at more summarized and higher levels of the data and view numeric values. When a measure is placed on a shelf, by the process of summing it Tableau automatically aggregates the data. When it is placed on a shelf, the function always shows in front of the field’s name, so that we can easily determine the aggregation applied to a field. For instance, Sales appears as SUM. But using Tableau, the measures can be aggregated only for relational data sources. Only the aggregated data is contained in multi-dimensional data sources. Only the Windows supports these multi-dimensional data sources.
Question 8
Explain the concepts of Schedules and Extracts in Tableau server?
Answer : The extracts and workbook get refreshed only when a scheduled refresh on the extract is applied by the users. In order to get them refreshed during the publication of a workbook with data extract, the scheduling tasks that are set for data extract are called Scheduled Refreshes. So we do not have to republish the workbook every time during the upgrade of the data.The subdivisions or the first copies of the original data from the actual data sources are known as data extracts. Since the extracted data is imported into Tableau Engine, workbooks that use the data extracts are faster, unlike those using live DB connections. Users can publish the workbook that also extracts and publishes in Tableau Server after this extraction of data.
Question 9
Describe the TDE file?.
Answer : A .tde extension is found in the Tableau desktop file in the TDE file. Data that is extracted from external sources like MS Access, MS Excel and CSV file are included in this file Tableau Data Extracts (TDE) file. The TDE design is the ideal choice that supports data discovery and analytics and it has two major aspects.
Primarily, TDE is a columnar store. The processes of memory loading and its usage by Tableau is impacted by the way of its very structure. So TDE is known for being “architecture aware”. TDE puts each part of the computer memory, from hard disk to RAM, to work what best fits its features.
Primarily, TDE is a columnar store. The processes of memory loading and its usage by Tableau is impacted by the way of its very structure. So TDE is known for being “architecture aware”. TDE puts each part of the computer memory, from hard disk to RAM, to work what best fits its features.
Question 10
Explain in detail default Data Blending Join?
Answer : Without having to draw up any special coding, data blending brings up into one Tableau view the data from the multiple data sources. A left outer join can resemble a default blend. It is probable to reproduce the right, left, and inner joins by filtering nulls and switching the primary data source.
Question 11
Explain Disaggregation in Tableau?
Answer : When we do analyze measures that may be used both dependently and independently in the view, if we are able to view every row of the data source, it is because of disaggregating of the data. If in case we want to analyze with the age of participants along one axis when we do a product satisfaction survey, we can disaggregate the data to figure out at what age participants were most satisfied with the product and we can determine the average age of participants by aggregating the age field.
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Question 12
Distinguish continuous and discrete in Tableau?
Answer : There is two dimension of data roles in Tableau, namely continuous and discrete types.
Continuous data takes into account any value within an infinite or finite interval and it is used to measure continuous data. Order quantity, profit, time, and the unit price comes into this category. And continuous variables can take on any value as they can be seen in that same way.
Discrete data takes only the individual values within a range and it is counted as separate and distinct. Customer name, State, threads in a sheet, and row ID are these categories.
Continuous data takes into account any value within an infinite or finite interval and it is used to measure continuous data. Order quantity, profit, time, and the unit price comes into this category. And continuous variables can take on any value as they can be seen in that same way.
Discrete data takes only the individual values within a range and it is counted as separate and distinct. Customer name, State, threads in a sheet, and row ID are these categories.
Question 13
In Tableau, what is blended axis?
Answer : In Tableau, all the marks are shown in a single pane if the measures can have in common a single axis. All of the values for each measure is shown along one continuous axis and there is a single column or row when we do blend the measures and it can be done instead of adding columns and rows. We can just drag an axis or a measure and drop it onto an existing axis, thus blending multiple measures.
Question 14
In Tableau, How can we do the Performance Testing?
Answer : To implement Tableau, the process of Performance Testing is crucial. A “Point and Run” load generator created to perform QA – TabJolt – and by loading Testing Tableau Server with it, we can do it easily. TabJolt is installed using other open source products although Tableau does not support it.
Question 15
Explain the differences between twbx and twb file extensions.
Answer : .twbx eliminates to obtain the permissions from the end user by storing the data as a zip file or a package and it takes the data offline. It is saved as .twbx since it is a snapshot in time.
Twb relates and points to the data source and it is a live connection. Permission has to be obtained for the users receiving twb, without which the data is not included.
Twb relates and points to the data source and it is a live connection. Permission has to be obtained for the users receiving twb, without which the data is not included.
Question 16
What are the main differences between the traditional BI tools and the Tableau Software?
Answer : Even though traditional business intelligence can handle the tasks, it comes with a huge cost of the software and the higher consulting. It is notable that only Microsoft has the reasonable value offer among the prominent vendors. And the value and cost-effective qualities are not found among JasperSoft and Pentaho, other open source vendors.
Apart from the issues with the data foundation, Tableau provides a vast amount of services like Visual Analytic capabilities. We can have a complete package by combining both Tableau and SQL Server.
Apart from the issues with the data foundation, Tableau provides a vast amount of services like Visual Analytic capabilities. We can have a complete package by combining both Tableau and SQL Server.
Question 17
Define data modelling?
Answer : Data modelling is inevitable when it comes to object-oriented programming and Data modelling is used primarily to the identification of the relationships among the data objects that are used in a business or other context and it analyses the data extensively.
Question 18
How is the workbook scheduled and published in the tableau server?
Answer : A schedule for the particular time should be created and publish the workbook for the server by creating the extract for the data source. To create and publish, click and schedule the option Scheduling and Authentication from the drop-down. And then we could assign the schedule and publish the data source. The workbook will be refreshed and for the assigned time the schedule automatically runs.
Question 19
How is Tableau integrated with R?
Answer : For the statistical analysis, we cannot skim R, a popular open-source environment. Tableau desktop can be used to take advantage of the libraries, functions, saved models, and the packages by connecting to R through calculated fields. The values are passed via the Rserve package since these calculations dynamically instigate and triggers the R engine and, in the end, returns back to Tableau. Anyone can view the dashboard that contains the R functionality by configuring the Tableau Server to be connected through the tabadmin utility to an instance of Rserve. We can bring deep statistical analysis into a visual analytics environment of drag-and-drop by linking Tableau with R.
Question 20
How to view SQL, a creation of the Tableau Desktop?
Answer : We can check the log.txt and tabprotosrv.txt files of we do have the live connection to the data source. The C: UsersMyDocumentsMy Tableau Repository contains the Tableau Desktop Log files. To view the detailed information about queries, we can use the tabprotosrv.txt file. It is important to check the tdeserver.txt file if we do use an extract.
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