# Transformation strategy with Tableau Prep flows

*Tableau Consultant Study Guide · Plan and Prepare Data Connections · Last updated November 3, 2026 · https://www.certifyforce.com/study-guide/tableau-consultant/plan-and-prepare-data-connections/transformation-strategy-with-tableau-prep-flows*

Decide where each transformation belongs (a Tableau Prep flow, a workbook calculation or the physical layer of the data model), pick the right Prep step for the job, and spot what a flow cannot do on Tableau Cloud.

- Certification: Salesforce Tableau Consultant
- Exam section: Plan and Prepare Data Connections
- Study guide: https://www.certifyforce.com/study-guide/tableau-consultant

**Official exam objective:**

> Recommend an appropriate data transformation strategy.

## What the exam expects

- Recommend whether a transformation runs once in a Tableau Prep flow or stays in the workbook because it depends on viewer input.
- Choose the Prep step for a shaping problem: pivot, Aggregate before a join, union, Group Values or a data role.
- Flag flow features that won't run where the flow is published, such as script steps on Tableau Cloud.
- Rewrite a slow workbook calculation, and move a filtering join into the physical layer.

Key terms:
- **Flow:** a Tableau Prep sequence of steps from Input to Output.
- **Grain:** the level of detail one row represents.
- **Data role:** a Prep field setting that validates values against a known domain or pattern.
- **Physical layer:** joins and unions inside one logical table, below the relationships canvas.

## Key facts

| Fact | Detail | Source |
|---|---|---|
| Flow outputs | File (Prep Builder only), published data source or database | [Get Started with Prep](https://help.tableau.com/current/prep/en-us/prep_get_started.htm) |
| Scheduled flow runs | Need Data Management with Tableau Prep Conductor enabled | [Get Started with Prep](https://help.tableau.com/current/prep/en-us/prep_get_started.htm) |
| Where calculations run | Basic, aggregate and LOD in the database; table calculations on the result set | [Efficient Calculations](https://help.tableau.com/current/pro/desktop/en-us/perf_efficient_calcs.htm) |
| Union step inputs | Performance tip: at most 10 per union step; union more in the Input step | [Aggregate, Join, or Union](https://help.tableau.com/current/prep/en-us/prep_combine.htm) |
| Pronunciation, Common Characters | Not available for data roles | [Clean and Shape Data](https://help.tableau.com/current/prep/en-us/prep_clean.htm) |
| Grouping threshold | Groups are saved; the slider setting is not | [Clean and Shape Data](https://help.tableau.com/current/prep/en-us/prep_clean.htm) |
| Email and URL roles | Validated against patterns; invalid values get a red exclamation point | [Data roles](https://help.tableau.com/current/prep/en-us/prep_validate_data.htm) |
| Custom data roles | Page says retirement is set for Tableau Cloud February 2024 and Tableau Server 2024.2 | [Data roles](https://help.tableau.com/current/prep/en-us/prep_validate_data.htm) |
| Script steps | Not supported on Tableau Cloud; Server needs Rserve or TabPy | [R and Python scripts](https://help.tableau.com/current/prep/en-us/prep_scripts.htm) |

## Check yourself

- When you reopen the Group Values editor after adjusting the Spelling slider, where does the slider sit?
- Why does Tableau suggest Display As for a string-type parameter used in a calculation?
- Why can filtering out NULL values from unmatched rows make a related data source faster?
- What does the data-roles page say is retired in Tableau Server 2024.2 that affects data-role validation?

## Sources

- [Get Started with Tableau Prep Builder](https://help.tableau.com/current/prep/en-us/prep_get_started.htm)
- [Clean and Shape Data](https://help.tableau.com/current/prep/en-us/prep_clean.htm)
- [Aggregate, Join, or Union Data](https://help.tableau.com/current/prep/en-us/prep_combine.htm)
- [Create Efficient Calculations](https://help.tableau.com/current/pro/desktop/en-us/perf_efficient_calcs.htm)
- [Use Data Roles to Validate your Data](https://help.tableau.com/current/prep/en-us/prep_validate_data.htm)
- [How Analysis Works for Data Sources that Use Relationships](https://help.tableau.com/current/pro/desktop/en-us/datasource_multitable_analysis_overview.htm)
- [Use R and Python scripts in your flow](https://help.tableau.com/current/prep/en-us/prep_scripts.htm)
- [Pivot Your Data](https://help.tableau.com/current/prep/en-us/prep_pivot.htm)
- [Add More Data in the Input Step](https://help.tableau.com/current/prep/en-us/prep_add_input_data.htm)

## About the full unit

The "Core concepts", "Exam traps" and "Worked scenario" sections of this unit, its 8 linked practice questions, and unlimited timed mock exams are included with the Tableau Consultant pack (USD $19): https://www.certifyforce.com/practice-exams