Metadata refers to information about the data itself. Nearly every database contains some metadata. This includes lists of the tables and fields for a data source and what type of data (for example, numeric, string, or date) a field contains. Tableau provides an additional layer of metadata that makes it very easy to customize a data connection to add or change attributes of the data.
Right-clicking on a field in the Data window reveals a menu of metadata options. Some of these options will be demonstrated in the following exercise, and others will be explained in later chapters. These are some of the options available via right-click:
Rename the field
Redefine the field as a dimension or a measure
Change the default use of a field to either discrete or continuous (this can only be done for date and numeric fields)
Add or remove the field from a hierarchy
Change the data type of the field
Change the geographic role of a field...