About this course
In this presentation as promised in an earlier video we begin by delving into table relationship modelling....
In the real world, on occasions, you are more than likely find yourself with tables that hold the same values.
Assuming you do attempt to form a relationship with duplicate table value columns you will see the following error message ‘You cannot create a relationship between these two columns because one of the columns must have unique values.’ In other words, you will be prevented from doing so.
This presentation will show you one work around solution to this problem and to do that, we first need to create a new query, appending values from both the existing tables....
What is a many-to-one relationship?
Relationships in Power BI: Fixing “One of the columns must have unique values” error message
When you import multiple tables, chances are you’re going to do some analysis using data from all those tables. Relationships between those tables are necessary in order to accurately calculate results and display the correct information in your reports.
Sometimes the data you’re analysing just doesn’t contain a particular field you need to get the results you’re after. This is where calculated columns come in. Calculated columns use Data Analysis Expressions (DAX) formulas to define a column’s values.
Changing data types, for example, a number to a currency value will help report readers to quickly focus on the key points of interest. So, it’s worth spending a little time on data types.
DAX empowers us to ask incisive and powerful questions of data. You define your question once and you can then slice your data by as many different fields as you want. An example would be time-based calculations.
Calculated tables allow you exact data of interest from several tables to create a new table from which you can answer questions and in turn, generate reports you couldn’t do any other way.
There will be occasions when you will want to analyse data over time, for example by year, quarters, months and days. Thankfully using Power BI this is relatively easy as fields can be automatically generated.
There may be occasions when you have been working within Excel and you would like to copy the worksheet to create a new table in Power BI. This video will show you how you can manually type in the data or paste data into a new Power BI table.
The workshop is an important opportunity for you to confirm what you do or don’t understand. Mistakes are often a better learning experience than getting everything right the first time so if you do make mistakes no one needs to know. On the positive side, you are unlikely to repeat your error. Good luck.
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