Reverse Polarity RELATED()

October 3, 2013


Guest post by Ken Puls

I was recently working on an interesting thing in PowerPivot, and thought I’d share it in case it may help someone… A quick summary of the issue is that I needed to examine multiple records in a child table, and return a single result to the parent table if a condition was present; something that goes against the normal relationship flow.

Scenario Background

I have a file that tracks the purchase and sale of land, as well as the respective property taxes and assessments that we get on an annual basis. It is set up like this:

9-17-2013 2-56-59 PM

At first glance this might look complicated… Each Parcel is assigned a unique Parcel Identifier, known as a PID, a key identifier that will never change for a piece of property.  This info is then used to identify that parcel by the tax authority, the assessment authority, and our appraisers and accounting systems.  In the case above, we can see that the PID from the Parcel table links to the Transaction, Taxes and Assessments tables. From the other side we’ve got the Key_Date that links back to the three tables as well, although it links to TranDate, TaxYear and AssessYear respectively.

Read the rest of this entry »

The Dreaded “One to One” Relationship, or Why “Boaring” Movies Are Best

June 4, 2013

Another Example of “Relationship May Be Needed” When You Do, In Fact, Have a Relationship

Let’s pick up the topic from last week and examine another instance where you might encounter the dreaded warning message above.

Let’s start with this simple pivot:


Which is a column from the Years table and a column from the Movies table:


But now I have a new table:  Animals, which simply lists, for each year, which Animal is specified by the Chinese Zodiac:


Hollywood Insiders Know That the Animals of the Chinese Zodiac Are
Incredibly Important to Box Office Revenues


Read the rest of this entry »

“Relationship may be needed?” But I already have a relationship! What’s going on?

May 30, 2013


“Well I’m not quite ready for a relationship right now Lois.”

A confusing error getting you down?

I got an email this morning from a friend who was running into this problem:

PowerPivot says "Relationship may be needed" - but you do have a relationship.  What's going on?

Are you getting this warning in the field list,
even though you DO have a relationship in place?

What gives?  Let’s return to our recent movies example.

To help you diagnose this problem, should you run into it, first let’s get a simple example ready.

Two tables of data in PowerPivot:  Movies, and Years.

Read the rest of this entry »