[Tableau Desktop Specialist Certification] Exam Prep - Practice Exams (Mock Exams & Notes)

[ Connecting to & Preparing Data ] 

Q. How to reduce the size of an extract ?

A1) Aggregate the data to visible dimension

A2) Hide All Unsued field

 

=> When we create an extract, we get many size options

We can choose only include a sample of the data,

Or aggregate to visible dimensions 

Or use extract filters 

Or choose the physical table option instead of logical table 

 

 

Q. The best reason to use a live connection instead of an extract?

A) You need to refresh the data as often as possible 

 

=> live connection과 extract의 차이점 

1) live connection에서 data에 접근하기 위해서는 residential 필요, extract 은 필요 X. 

2) workbook이 data source에 연결되어 있지 않은 경우(=오프라인일 때) live connection은 작동 X, extract 작동 O 

3) Extract은 size 조정이 가능하다 (데이터 로딩 타임을 줄여줌, 위의 문제 참고) 

4) incremental loads : 새로운 데이터만을 추출하여 기존 데이터에 추가

only the new data is refreshed ( reduce the data loading time but unlike to reduce the size ) 

- 테이블 계산의 계산 과정과 결과를 포함하지 않고, 원본 데이터의 요약 정보와 필요한 데이터만을 추출에 저장한다 

- 작업 시간과 리소스 절약가능 

=> Live Connection을 사용할 때는 데이터 원본에서 데이터를 실시간으로 쿼리하므로, incremental loads 적용 X 

( Live Connection : 실시간 데이터 업데이트 및 로드가 필요한 경우 ) 

=> Extract Connection을 사용할 때는 데이터를 추출하고 Tableau 데이터 엔진의 .hyper 파일 형식으로 변환하여 데이터를 처리하기때문에, 이와 관련된 incremental loads및 데이터 업데이트가 가능하다 

( Extract Connection : 데이터 원본에서 데이터를 추출하여 정기적으로 업데이트하고, 대시보드와 보고서를 실시간으로 업데이트 )

 

 

Q. This File type saves both the connection information(ex, database server address), calculation and groups that you've add, along with an extract of the data? 

A) .tdsx (=Tableau packaged data source) 

 

=> File types in Tableau

- Tableau workbook (.twb)

- Tableau packaged workbook (.twbx) : Tableau workbook + extract

 

- Tableau extract (.hyper(newer ver) and .tde) 

 

- Tableau data source (.tds)

- Tableau packaged data source(.tdsx) : information of data source + extract

 

 

Q. How to create a tds file

A1) On data pane, right-click the data source, and then select Add to Saved Data source

A2) By selecting Data on the toolbar, selecting the data source, and then selecting Add to Saved Data source

 

 

Q. A relationship is most similar to which type of join?

A) Outer Join 

( blend -  Left Join과 유사 ) 

 

=> Relationship : default to use 

- relationship은 logical layer에 존재 (logical table끼리의 결합) 

- to ensure that all values from both tables in the relationships are included, we can add a measure to the view

- relationship은 Join과 달리 한 테이블로 합쳐지지 않고 각각 테이블을 유지 (relationships keep the tables seperate)

- relationships don't query data unless columns from that table are used in the viz. 

- relationships don't work with geographic fields.

 

=> Join :

- Join은 하나의 combined된 테이블을 생성한다. physical layer에 존재(physical layer: 데이터 소스와 실제로 연결됨) 

- a row is added each time the join criteria is met, which can result in duplication

조건 충족 시마다 row가 추가 됨 -> 중복 발생!

( left, right, full outer join - the null is assigned for the empty value ) 

- Join은 데이터를 먼저 combine한 후, aggregate 실행 

 

 

Q.Which can be used to combine tables at different levels of granularity without duplicating data? 

A1) Relationship

A2) Blend

 

( granularity : 데이터의 세분화 정도나 데이터 항목의 상세함, 더 세분화 된 데이터일 수록 더 낮은 granularity을 가짐 ) 

=> Blend: with a blend, a primary data source is linked to a secondary data source.

- the data in the secondary data source will not be duplicated even if the linking criteria is satisfied multiple times. 

-  Unlike joins, data blending keeps the data sources separate and simply displays their information together.

- blend는 aggregate한 후, data combine 실행 (<-> Join) 

- Blends and cross database joins can combine tables stored in different databases.

 

< Manage data properties > 

- Field names, parameters, sets can be renamed ( 워크 시트에서 새로 생성 된 것은 rename 가능 )

- Aliases can be set only for discrete dimensions.(dimension field)

- Default properties which can be assigned to a dimension: Comment / Color / Shape / Sort 

- Default property for a measure : Comment / Color / Number Format / Aggregation / Total Using

 

 

 

[ Exploring & Analyzing Data ]

Q. The chart would be most appropriate for showing the relationship between two measures?

A) Scatter chart 

 

=> Scatter chart  : Scatter plots allow us to visualize the relationship between two or more measures

- can add trend line *best line

 

Q. The feature to organize related dimensions into a series of different levels?

A) Hierachy

 

=> Hierachy : establish relationship between dimensions 

 

 

 

Q. The steps needed to do a manual sort?

A1) Right-click the pill for the dimension you'd like to sort. Select Sort, then Manual 

A2) Use the arrows to manually click okay. Click a header and drag it to the new location (just drag&drop)

 

 

Q. How to change a line chart into a bar chart? 

A1) On the Marks card, select Bar from the drop-down list

A2) On the Show Me menu, select horizontal bars 

 

 

Q.  How can totals be added to crosstab view? 

A1) Select the Analytics Pane. Drag totals into view release the mouse on the type of total you'd like to add

A2) On the Analysis tab of the toolbar, select totals. Then select the type of total you'd like to add 

 

=> Crosstab : a term that means text table 

 

 

Q. We want the user to be able to choose to have other measures shown in the same format. 

How we could achieve this?

A) With a Parameter

 

 

=> when to use a parameter? 

parameter : 사용자가 대시보드나 워크시트 내에서 값을 선택하거나 입력할 수 있는 동적인 설정 요소

- parameter(=변수) : 상수값으로 대체 가능한 숫자, 날짜, 그리고 문자열을 변수화해서 사용 (true/false: boolean 반환)

- 계산식 활용 가능 

- filtering 가능 (날짜 범위를 선택하거나 특정 카테고리를 선택할 때 매개변수를 활용하여 데이터를 동적으로 필터링) 

- 대시보드에 제어 요소 추가 (사용자 인터페이스 요소(예: 드롭다운 목록, 슬라이더)를 추가)

 

* Simply adding a parameter will not change the view. You'd need to use the parameter as part of a calculation or filter to change the view.

 

 

Q. How to change the dimension filters to context filter? 

A) Right click on dimension pill > drop-down menu, click 'Add to Context'

 

=> Order of Operation in Tableau (실행 순서 - filter 적용시 중요!) 

=> Line chart :  Line charts always involve a date dimension.

(라인차트는 무조건 date를 항상 포함!)

line chart의 종류 - discrete / continuous lines (date는 둘 다 표현될 수 있음) 

 

- A dual line chart shows two different measures changing a date range. ( 1 date + 2 measures) 

( dual line 차트에서 각 Axis의 스케일이 다른 경우 : 오른쪽 scale 우클릭 > drop-down menu, Click 'Synchronize Axis' ) 

 

=> reference line

: Analytics pane > Drag 'Reference Line' 

- Scope : Table / Per Pane / Per Cell 

 

=> Group : groups can be created on measures and dimensions.

- a method for combining values of a measure

- a method for combining values of a dimension

- helpful in combining all values of a field containing a given string

 

* Groups and sets combine values within a field while hierarchies allow you combine similar fields.

 

=> Set : Sets determine which values of a dimension are in the Top N or Bottom N based on a related measure

 

=> Histogram : viewing the distribution of a measure (+ box plot도 동일)

- A bin can be created on a continuous measure or numeric dimension.

- A histogram always bins data and uses the COUNT (also shown as CNT) or COUNT DISTICT(COUNTD) funtion to count the number of occurences within the bin.

* A histogram shows the distribution of continuous data by creating bins that are discrete.

=> quick table calculation

- Total is a table calculation

- A table calculation can show the difference between the current and prior month.

 

 

Q. How to create a cumulative sum of the values

A) Right-click the pill for the measure in the view, select quick table calculation and the select 'running total'

 

 

Q) How to add totals to the view below:

1) On the Analysis pane, drag Totals into the view and drop on the Row Grand Totals area

2) Select the Analysis option on the toolbar, then Totals and Add Row Grand Total

=> Create a calculated field

- string calculation

- date calculation

- simple arithmetic calculation

 

 

 

[ Sharing Insights ] 

Q. The interactive elements you can add to a dashboard?

A) URL Actions, Highlight Actions, Filter Actions

 

=> Dashboard 

- dashboard can't include the story 

- actions in dashboard : Filter, Highlight, Go to URL, Go to Sheet, Parameter, Set

 

 

Q. How to create the dashboard action? 

A) Click the "More Options" arrow on the worksheet included in the dashboard layout, then select "Use as filter"

=> When you use the 'Use as Filter' option to create a dashboard option, the action will be run on ​select.

 

 

Q. You'd like to add the same worksheet multiple times, but with different filters selected.

Which feature will support this?

A) Story

 

=> Marks card

- In a Tree map, it's not possible to adjust the size of the marks.

- Polygon chart size can't be adjusted.

- Mark type in Area chart cannot be adjusted using the Size slider.

 

- Mark size options for a continuous measure: Range / Reversed

 

=> legend 

- size legend 

 

- color legend

=> options in changing the color in Quantitative legend 

·       Stepped Color - groups the values into uniform bins each given a unique color.

·       Reversed - switches the order of the colors in the range.

·       Use Full Color Range 

 

- shape legend

=> The shape legend can only represent categorical data, that is discrete categories such as products and regions.

 

 

Q. you’ve created a crosstab view with dimensions and an aggregated measure. What steps should you take to export the crosstab to excel?

A) Select Worksheet > Export > 'Crosstab to Excel' 

 

 

Q. toobar icon starts the process of publishing the workbook to server

+ Or Server > Publish Workbook

 

 

Q. Which type of filter usually works best with date fields?

A) Slider filters

=> slider filter is good for date numerical values

(List filter is better for categorical data)

 

 

Q. Which of the following will result in an error?

A) Aggregation on a field that is already aggregated

 

 

 

[ Understanding Tableau Concepts ]

Q. Which of the following will create an axes when it is added to the row or column shelf?

A) A continuous measure, a continuous dimension

 

 

< DISCRETE vs CONTINUOUS > 

* DISCRETE (blue pill)

-  creates headers 

- A discrete field create a color palette.

- Discrete date aggregates data at the selected unit

 

* CONTINUOUS (green pill)

- creates axes 

- A continuous field will create a color gradient

- string / boolean can't be continuous

-  Continuous date uses individual date values

 

 

 

< DIMENSION vs MEASURE > 

* DIMENSION

-  usually contains qualitative values(such as name, dates, or geographical data)

- can be used to categorize segment and reveal the detail in the data

- Dimensions affect the level of detail in the view. (If more dimension are added to the view, the level of detail in the view increase )

- used for categorical and descriptive attributes that help organize and label data

- Tableau displays a categorical palette and assigns a color to each value of the field

 

* MEASURE

- usually contains quantitative values

- can be aggregated

- used for numerical values that are subject to analysis, aggregation, and calculations

- Tableau displays a quantitative legend with a continuous range of colors