Friday, March 8, 2013

[TABLEAU] Accessing Data Offline Using Data Extracts



  Accessing Data Offline Using Data Extracts

Extract the Entire Data Source  

Although you may usually connect to a data base online, you can use data extracts to save subsets of the information so you can view and analyze it anywhere. For example, you can extract information from your company's data base so you can take it with you to analyze during a long flight. Begin by connecting to the data source from which you want to extract some information. The entire underlying data source can be copied to an Extract, or the extract size can be filtered on specific field values or reduced to a specific number of rows.



Depending on the size of the data source you may just want to extract the whole thing. Follow the steps below to extract the entire data source.


Step 1
Connect to the data source you want to extract from, select the data source in the Data menu, and then select Extract Data.




Step 2
Make sure that the All option is selected for Number of Rows and click Extract.






Extract Specific Rows

If the data source is really large or contains a lot of unneeded data, you can reduce the size of the extract by adding filters and limits. Follow the instructions below to extract a portion of the data source.

Step 1
In the Extract dialog box, click the Add button in the Filters area. In the subsequent dialog box, select a field and click OK.





Step 2
In the Filter dialog box, select the members you want to include in the extract. You can also specify conditions and limits such as the top 20 members based on another field or all members greater than a specific value.


 

Add as many additional filters as desired to narrow the amount of data you include in the extract.

Step 3
To extract all the rows that satisfy the filter values, make sure that All is selected for Number of Rows and click Extract.



Extract a Sample of Rows

Rather than extract the entire data source, you can instead take a sampling of rows. You can also define a set of specific set of data to include and then extract just a sample of them using the Number of Rows settings. Follow the instructions below to specify a subset of the data based on the number of rows.

Step 1
In the Extract dialog box, optionally specify filters using the instructions above. Then specify the number of rows to include. You can select all, a percentage, or a specific number of rows. Depending on the data source, an additional dropdown menu with further options for a percentage or specific number or rows may be available.




Step 2
When finished click Extract, and save the extract under a descriptive name.
The icons in the Data window indicates that you are now connected to an extract file.



Note: While creating extracts is a great way to access subsets of information from large data sources offline. You can also use it to add advanced functionality to limited data bases and improve performance.





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