Specialist Practice Questions – Additional Questions for Connecting to & Preparing Data 오답 노트
- 본 포스팅은 유데미의 Tableau Desktop Specialist Certification Prep 강의 중 섹션 4: Connecting to & Preparing Data의 Additional Questions for Connecting to & Preparing Data의 내용을 토대로 작성되었음을 밝힙니다. 보다 정확한 내용은 아래 링크를 참고하세요.
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정답률 69% (9개/13개)
보라색 글자는 Tableau Desktop에서 실습해보거나, 추가 검색/정리 등 정확한 확인이 필요한 부분입니다.
1. 틀린 문제
7. Which option leads to adjusting the granularity of data in Tableau? [1.2.2 Add joins and unions]
a) Aggregate
b) Group by
c) Grouped Fields
d) Extract
SQL의 집계함수인 group by와 헷갈림😣 -> 'granularity'에 hierachy나 group을 떠올림 -> b)와 c)가 'Create group랑 관련이 있는건가' 했다.
하지만 태블로에서 집계를 통해 granularity(LOD)를 만들어내는 것은 글자 그대로 Aggregate!
group, set, hierachy는 Organize data and apply filter와 관련된 내용이다.
Correct answer: a, Aggregate
Explanation: To adjust the granularity of the data, we use the Aggregate option to create a step to aggregate or group data.
8. Advantages to using relationships to combine tables: [select all that apply] [1.2.3 Explain when to use a join versus a relationship]
a) Makes it easier to change the key fields used to combine the tables
b) Make it easier to analyse data across multiple tables at different levels of granularity
c) Makes it easier to combine rows from one table with rows from another
d) Tables are only queried when fields from the tables are added to the viz.
[1.2.3 Explain when to use a join versus a relationship]
Correct answer: b, d.
Explanation: Changing the key fields is a similar process with relationships and joins. Relationships do not combine rows from one table with rows from another. They do have the other benefits listed: duplication is avoided when tables are combined with different levels of granularity and tables are only queries when required in the worksheet.
10. Aliases cannot be created for the following – [select all that apply] [1.3.2 Assign an alias to a data value]
a) Discrete dimension
b) Continuous dimension
c) Measures
d) Dates
[1.3.2 Assign an alias to a data value]
Correct answer: b, c, d.
Explanation: In Tableau aliases can be created for the members of discrete dimensions only. They cannot be created for continuous dimensions, dates, or measures.
13. Choose the correct path to add a default comment for a field- [1.3.5 Change default properties for a data field (number format, aggregation, colour, date format, etc.)]
a) Right click a field in the Data pane-> Default Properties-> Comment
b) Right click a field in the Data pane-> Aggregation -> Default Properties-> Comment
c) Right click a field in the Data pane -> Comment
d) Right click a field in the Data pane-> Describe-> Comment
comment = 댓글
[1.3.5 Change default properties for a data field (number format, aggregation, colour, date format, etc.)]
Correct answer: a.
Explanation: Right-click (control-click on a Mac) a field in the Data pane and select Default Properties > Comment. Write a comment in the subsequent dialog box. Comments support rich text formatting that will be represented in the tooltip.
2. 헷갈린 문제
1. [1.1.1 Create a live connection to a data source] How can the users refresh an extract immediately in Tableau desktop? (Multiple Possible Answers)
a) Select a Data Source on Data Menu -> Extract
b) Select a Data Source on Data Menu -> Extract -> Refresh
c) Sign in to Tableau Server -> Click Tasks at the top of the page -> Under Extract Refreshes select the workbook or data source -> On the Actions menu click Run now.
d) Select a Data Source on Data Menu -> Extension -> Refresh
Correct answer: a, b, c.
Explanation: In Tableau in several way user can immediately refresh an extract either by going to extract and then select refresh or by manually selecting data source or workbook under extract refreshes and click on run now under Actions menu. (https://help.tableau.com/current/online/en-us/to_refresh_extract_manual.htm) Also there is no option in Data Menu called ‘Extension’.
2. [1.1.2 Explain the differences between using live connections versus extracts] What Is The Difference Between Live And Extract Connections. (Multiple Possible Answers)
a) Live allows real-time data while extracts are kind of batch which needs to be refreshed from time to time to get the updated data.
b) Live Connection takes more time to load data than Extract Connection.
Correct answer: a,b.
Explanation: In the case of live connection whatever changes will be done at the Datasource end that will be directly available to the tableau desktop. While in case of extracting any changes made in the data source won't reflect in the report immediately. It will be reflected when the extract will be refreshed. Also, we need to apply an aggregation that takes too long when using a live connection which results in delaying working with the dataset. Live connection might slow down operational queries too much, so having Tableau only query at scheduled extract refresh times is preferable.
3. [1.1.3 Create an extract] Why the direct connection to the extract is not recommended – (Multiple Possible Answers)
a) The table names will be different
b) The extract cannot be refreshed
c) The data model and relationships will be lost.
d) The extract cannot be removed once it is connected directly.
Correct answer: a,b,c.
Explanation: We can remove an extract at any time by selecting the extract data source on the Data menu and then selecting Extract > Remove. Tables stored in the extract use special naming to guarantee name uniqueness, and it may not be human-readable. We cannot refresh the extract. When connecting directly to an extract, Tableau treats that file as the true source, as opposed to a clone of underlying data. So, it's not possible to relate it back to your source data. The data model and relationships will be lost. The data model and relationships between the tables is stored in the .tds file and not in the .hyper file, so this information is lost when connecting directly to the .hyper file.
5. [1.1.5 Create a data source that uses multiple connections] How many data sources can we blend in Tableau?
a) Two
b) Three
c) Four
d) Five
Correct answer: a, Two.
Explanation: The two sources involved in data blending are referred as primary and secondary data sources. A left join is created between the primary data source and the secondary data source with all the data rows from primary and matching data rows from secondary data source.
9. [1.3 Manage data properties] [1.3.1 Rename a data field] Select the correct pathway to edit the data source
a) Data Menu -> Select a Data source -> Edit Data Source
b) Data Menu -> Select a Data source -> Extract Data
c) Data Menu -> Select a Data source -> View Data
d) Data Menu -> Select a Data source -> Edit Data Source Filters
Correct answer: a.
Explanation: On the Data menu, select a data source, and then select Edit Data Source. And, then on the data source page, make the changes to the data source.
12. [1.3.4 Change data type for a data field (number, date, string, Boolean, etc.)] Choose the correct path to change the data type for a field in the view
a) Right click the field in the Data pane -> Change Data Type -> Data Types -> Choose the appropriate data type
b) Right click the field in the Data pane -> Change Data Type -> Choose the appropriate data type
c) Right click the field in the Data pane -> Data Types -> Choose the appropriate data type
d) Right click the field in the Data pane -> Choose the appropriate data type
Correct answer: b.
Explanation: To change a field's data type in a view, right-click (control-click on a Mac) the field in the Data pane, choose Change Data Type, and then select the appropriate data type from the dropdown list.