There are two ways of establishing data connections in Tableau. You can either use live connection to the underlying data sources or extract data to Tableau in-memory.
So, what is Tableau data extract?
Tableau Data Extract (.tde or .hyper) is a snapshot of data optimized for aggregation. This snapshot of data is loaded in Tableau’s in-memory where it can be quickly queried for visualization.
The Tableau data extract you create depends on the Tableau version you are using. For those using Tableau 10.4 and older versions – when you extract data, you get a file type (.tde) while for users of Tableau 10.5 to the current versions, extracting data generates a file type (.hyper) – the so called Tableau hyper.
Tableau hyper is simply the new in-memory data engine technology which provides 5X faster query speed and 3X faster extract creation speed than the tde.
Deciding whether to use live or extract connection will depend on a number of parameters, below we’ve shared some of the benefits you gain in using one of the above, just to guide you.
Benefits of Tableau extract
Using extract will help improve dashboards performance, especially when the underlying data source is terribly slow
Extracting your data allows you to work offline – ensuring continuity of your projects even when you are on holiday. You can also extract data to relieve server resources to handle other important operational activities.
Extracting your data allows you to implement calculations that might not be supported by your underlying database.
Help you keep data private by hiding fields in the data source while creating the extract – ensuring that people see only the data you need them to.
Benefits of live connection
Working with live data allows you to have real-time updates as the visualization is directly connected to the underlying data sources
Live connections are highly recommended when working with a fast database
How can I extract data in Tableau?
There are two ways you can extract data.
While at the data source page, select Extract >> select a new worksheet to extract data
On the dialogue box ‘Name your file’ and choose where to save it
While on the data pane >> right click on the data connection >> select Extract Data…
On the dialogue box, add filters if need be and select Extract
On the dialogue box ‘Name your file’ and choose where to save it.
Note: For Tableau public users, data is extracted by default as this tool works with data extracts
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