Data Connections in Tableau: Live vs Extract
Whenever we have to start anything in Tableau we need to establish a connection with data. In tableau we can do that in two ways:-
· LIVE Connection
· EXTRACT Connection
This can be again done in further two ways:-
1. Extract full data
2. Extract some data
In this connection Tableau creates a live communication path between data source and tableau. In Live communication path whenever data is changing in original data source it will be reflected on the tableau with a refresh.
Create a text file “Employee” in Notepad then in tableau click to link connect to data.
Then click on text file and then open employee file .
Select the connection type Live and click on view data. Then it will display data as below.
Adding a new row in the Employee text file and save it.
If we click on view data again it will not show the new row even though it’s a live connection for that we need to refresh. For that right click on the Employee data, then refresh and then again click on view data . Only then we can see the updated data.
In the extract connection whenever tableau connected with data source it creates a snap shot of data and place that snapshot in the component called Hyper analytic database engine.
Tableau data engine reads the data from snapshot and it creates a file known as Tableau Data Extract (.tde) or HYPER (.hyper)
Whenever tableau connects with data its actually connect with .tde/.hyper file instead of actual data.
Mechanism of Extract connection
In this again we need to connect employee file with tableau but instead of Live connection we will do Extract
It will automatically create a .tde/.hyper file and saves into Datasources of My Tableau Repository.
Again click on view data.
Updating one more row in employee text file .
It will not update automatically . For that we need to right click Employee data then go to Extract and then Refresh.
Once we refresh the data file we will get the update file.
Differences between Extract Vs Live Connections