TABLEAU INTERVIEW QUESTIONS
Difference between OLTP and OLAP ?
• Transactions that we do regularly like day in and day out to run the regular business will come under OLTP (Online Transaction Processing). They will contain more detailed data. Few examples of transactional databases are SQL server, Oracle, DB2.
• Transactions that come under analysis part can be grouped into OLAP (Online Analytical Processing). These transactions take more time to execute the past data based on the requirements.
What are dimensions and measures?
• Data set is classified into dimensions and measures. Dimensions are discrete in nature. Anything that is descriptive, which can be categorized, identified and qualitative in nature is called a dimension.
• Measure is continuous and quantitative in nature. Measure is something which adds weightage, and something which has a unit.
Dimensions and Measures have specific color on the workspace. Which colors they are associated with and what is their significance?
• Dimensions are shown in blue color and measures are associated with green color. Green color shows continuous representation and blue color will show discrete representation.
Types of Filters ?
• Following are the filters for dimensions.
Inclusion Filters: Whatever field values we select, only that associated values will be shown on the view.
Exclusion Filters: Whatever fields we select, that values will not be shown in the view. It is exactly opposite to the inclusion filters.
Wildcard: Wildcard will to a string match. It is useful for filtering the data in dimensions using alphabets.
Condition Filter: It is helpful in filtering the data based on a specific condition. Top: Filter the data by the field by top 10/bottom 10. Or even Filter it using top “parameter”
Calculation Filter : When we use a dimension in the filter shelf and if that dimension is not used in any other shelves then it is called as a calculation filter.
Context Filter : All the filters work independently. Whenver a filter is set as a context filter then all the other filters will act on the data that passes through the context filter. i.e. they are dependent on the context filter.
Difference between a filter and quick filter.
• Filters are used when the end user/client want to show specific data from a specific dimension or measure. We can filter the data by applying a filter on the dimensions.
• Quick filter appears on the right side of the view whenever a filter is applied. It helps to select required filter option in the view itself instead of going to the filter shelf.
Difference between discrete and continuous
What are the types of Axes? Explain.
1. We can go for an individual axis when both the measures have same/different units. As long as the axes are independent, there is no problem if the measures have same/different units.
2. We can use a blended axis if and only if both the measures have the same scale. So there is no problem as long as both the measures are weighed in terms of same units.
3. Dual axis, the name itself says both of the measures have different axes. We can go for a dual axis when both the measures have same/different scale.
What are 'cycle fields?'
When can a line chart prepared? And what is the dimension or measure that is required to generate a line chart?
When can we build a Map chart (Symbol Map, Area Map)? I.e. what is the mandatory field that is required?
Difference between symbol map and area map.
• In Filled Map, we can use maximum one measure because whatever the region/location is present, it will be filled with color. But we cannot change the shape of the region/state. So, maximum we can show the variation only in color.
Difference between Groups and Hierarchies.
What is 'Edit Locations' option on the 'Map' menu?
How can we convert a dimension into a measure or a measure to a dimension?
What is Synchronize Axis and where is it used?
How can we create a Line chart from an Area Chart without using 'Show Me?'
Difference between dual axis and dual combination.
What is 'Include Command Buttons' in ToolTip?
How to change the starting month for a Fiscal Year?
How can a duplicate sheet be created and how can a text table be created for a given sheet without using 'Show Me'?
• A text table is created for a given sheet by right clicking on the sheet and selecting duplicate as crosstab.