After connecting with the data source, Tableau captures the metadata details of the source, such as the columns and their data types. This is used to create the measures, dimensions, and calculated fields used in views. You can browse the metadata and change their properties for some specific requirements.
Checking the Metadata
After connecting with a data source all possible tables and columns will be displayed in the data source.
Example: The source ‘Sample Coffee Chain’ for checking the metadata.
- Click the Data menu and select to connect with a data source. Browse for the MS access file named as ‘Sample Coffee chain.’
- Drag the table which is named Product, to the data canvas.
- After choosing the file, you will get the below-given screen that shows the column names, and their data types. In Tableau, the string data types are shown as “Abc,” and Numeric data types are shown as “#.”
Changing the Data Type
You can change the data type for some of the fields (if required). Depending on the nature of the source data, sometimes Tableau may fail in recognizing the data type from the data source. In this structure, you can manually edit the data type. The below screenshot shows the options.https://imasdk.googleapis.com/js/core/bridge3.477.1_en.html#goog_1663365387
Renaming and Hiding
You can change the column names by using the renaming option. You can also hide a column, after that it will not appear in the data view. All these options are available after clicking on the data type icon in the metadata grid, you can see in the below screenshot.
Each column of the data source is assigned as aliases, which helps in better understanding the nature of the column.
Choose the aliases option from the above figure, and a screen comes up, which is used to Edit or Create the aliases.
Click on the OK button, and after that, you can see the changes in the column of the data sources.