4 Replies Latest reply on May 31, 2012 11:47 AM by steve.wright

    Rolename

      How are rolenames handled in Tableau?  For example, if you have a Date Dimension, and you have a Start Date and End Date in the Fact table with both columns pointing to the same Date dimension how is this specified in Tabeau?  Similar question for Ship From and Ship To columns in the Fact table that point at the same Geo Code dimension.

        • 1. Re: Rolename
          Tracy Rodgers

          Hi Steve,

           

          If both Start Date and End Dates are columns in the data source, then they will each come in as their own dimensions within Tableau.

           

          -Tracy

          • 2. Re: Rolename

            Thanks for your answer.  However, these are not date datatype columns--they are surrogate foreign key sequence ID fields pointing to the Date dimension table.  In effect, what we have here are multiple relationships between the same two tables with rolenames on each relationship.  This is a common design pattern in schemas and very common in data warehouses.  Another example in this data warehouse: we have a name/address table having Address_ID as the PK.  The Fact table has the columns Order_By, Recorded_By, Shipped_By, Received_By and each of these columns hold the value of an Address_ID record. Ideally, I'd like to load each dimension table only once.

            • 3. Re: Rolename

              OK.  I found the answer to my own question.  All you have to do is give your table a different unique Table Alias name each time it is reused and give each field a different Field Alias name that is unique across the connection.  I do not know if Tableau is smart enough to load the dimension only once.

              • 4. Re: Rolename

                It appears that while Tableau supports multiple rolename relationships between two tables there is a bug in how it names the attributes.  For example, if a Fact table has the columns Order_By, Recorded_By, Shipped_By, Received_By and each of these FK columns hold the value of an Address table PK then Tableau will create attributes with the name "Address1 City", "Address2 City", "Address3 City", etc.  You can try to rename these "Order By City", Recorded By City", etc. but when you save the workbook the renamed attributes revert back to the "Address1 City" default names.