# Live connections and extracts

*Tableau Desktop Foundations Study Guide · Connecting to and Preparing Data · Last updated October 29, 2026 · https://www.certifyforce.com/study-guide/tableau-desktop-foundations/connecting-to-and-preparing-data/live-connections-and-extracts*

How a live connection queries the source while an extract is a saved .hyper copy, when each fits, how to build an extract in the Extract Data dialog, and which settings (filters, hidden fields, Number of Rows, incremental refresh, storage) shape it.

- Certification: Salesforce Tableau Desktop Foundations
- Exam section: Connecting to and Preparing Data
- Study guide: https://www.certifyforce.com/study-guide/tableau-desktop-foundations

**Official exam objective:**

> Create live connections and extracts: Create a live connection to a data source; Explain the differences between using live connections versus extracts; Create an extract; Save metadata properties in a .TDS; Create a data source that uses multiple connections.

## What the exam expects

- Connect Tableau Desktop to a file or database from the Connect pane and recognize that a live connection queries the source directly.
- Choose between a live connection and an extract given a requirement: up-to-the-minute data versus speed, reduced database load or offline work.
- Create an extract from the Data Source page and the Extract Data dialog, and know that the workbook must be saved to keep using it.
- Shrink an extract with extract filters, hidden fields, aggregation and Number of Rows, and know what incremental refresh requires.
- Key terms: **live connection** (Tableau sends queries to the source and updates the view from the results); **extract** (a subset of the data saved separately from the original, in the .hyper format); **full refresh** (replaces all rows in the extract); **incremental refresh** (adds only rows that are new since the last extract); **extract filter** (limits which rows are extracted).

## Key facts

| Fact | Detail | Source |
|---|---|---|
| Connection types | Live Connection, Extract, Published Data Source; icon next to the data source shows which | [Refresh Data Sources](https://help.tableau.com/current/pro/desktop/en-us/refreshing_data.htm) |
| Live connection | Sends queries to the database; Data > Refresh shows saved source changes | [Refresh Data Sources](https://help.tableau.com/current/pro/desktop/en-us/refreshing_data.htm) |
| Extract | Subset saved separately from the source, in .hyper format | [Extract Your Data](https://help.tableau.com/current/pro/desktop/en-us/extracting_data.htm) |
| Extract benefits | Large data, performance, extra functionality, offline access in Desktop | [Extract Your Data](https://help.tableau.com/current/pro/desktop/en-us/extracting_data.htm) |
| What starts extract creation | Selecting a sheet tab after Save Settings | [Extract Your Data](https://help.tableau.com/current/pro/desktop/en-us/extracting_data.htm) |
| Keeping the extract | Connection to the extract is saved only when the workbook is saved | [Extract Your Data](https://help.tableau.com/current/pro/desktop/en-us/extracting_data.htm) |
| Default refresh | Full refresh replaces all rows | [Refresh Extracts](https://help.tableau.com/current/pro/desktop/en-us/extracting_refresh.htm) |
| Incremental refresh needs | All rows; not with Aggregation; not on a sample | [Refresh Extracts](https://help.tableau.com/current/pro/desktop/en-us/extracting_refresh.htm) |
| Hidden fields | Excluded from the extract; Hide All Unused Fields removes them | [Extract Your Data](https://help.tableau.com/current/pro/desktop/en-us/extracting_data.htm) |
| Physical Tables storage | Filters, aggregation, Top N and sampling disabled | [Extract Your Data](https://help.tableau.com/current/pro/desktop/en-us/extracting_data.htm) |
| Default data storage | Logical Tables | [Extract Your Data](https://help.tableau.com/current/pro/desktop/en-us/extracting_data.htm) |

## Check yourself

- What two choices does Data > (data source) > Extract > Remove give you?
- When is Physical Tables the wrong storage option for an extract?
- Why can an incremental refresh on a high-precision timestamp column produce duplicate rows?
- What happens if you choose Deactivate in the Extract Not Found dialog?
- Where does the extract go when you create it from a packaged .twbx workbook?

## Sources

- [Extract Your Data](https://help.tableau.com/current/pro/desktop/en-us/extracting_data.htm)
- [Refresh Data Sources](https://help.tableau.com/current/pro/desktop/en-us/refreshing_data.htm)
- [Refresh Extracts](https://help.tableau.com/current/pro/desktop/en-us/extracting_refresh.htm)
- [Connect to Your Data](https://help.tableau.com/current/pro/desktop/en-us/basicconnectoverview.htm)
- [Plan the Data Source](https://help.tableau.com/current/pro/desktop/en-us/datasource_plan.htm)
- [Data Source Page](https://help.tableau.com/current/pro/desktop/en-us/environment_datasource_page.htm)
- [Save Data Sources](https://help.tableau.com/current/pro/desktop/en-us/export_connection.htm)

## About the full unit

The "Core concepts", "Exam traps" and "Worked scenario" sections of this unit, its 6 linked practice questions, and unlimited timed mock exams are included with the Tableau Desktop Foundations pack (USD $19): https://www.certifyforce.com/practice-exams