Many-to-many relationships in Power BI Desktop (preview) - Power BI | Microsoft Docs
Power BI Desktop makes creating those relationships easy. .. a model from an older version of Power Pivot, where every relationship is set to. February 12, (iStock) In the stream of sorrows and quandaries and relationship angst, one word bubbles up again and again. First. My first love. My first time. Because long after it ends, our first love maintains some power over us. Today, after more than five years of marriage, he sees two versions of Denise. Each product we feature has been independently selected and reviewed by our editorial team. If you make a purchase using the links included, we may earn.
Many-to-many relationships in Power BI and Excel 2016
Autodetect during load If you query two or more tables at the same time, when the data is loaded, Power BI Desktop will attempt to find and create relationships for you. Cardinality, Cross filter direction, and Active properties are automatically set. Power BI Desktop looks at column names in the tables you are querying to determine if there are any potential relationships.
If there are, those relationships are created automatically. If Power BI Desktop cannot determine with a high-level of confidence there is a match, it will not automatically create the relationship. You can still use the Manage Relationships dialog to create or edit relationships.
In the Create Relationship dialog, in the first table drop-down list, select a table, and then select the column you want to use in the relationship.
In the to second table drop-down list, select the other table you want in the relationship, then select the other column you want to use, and then click OK. By default, Power BI Desktop will automatically configure the Cardinality directionCross filter direction, and Active properties for your new relationship; however, you can change these if necessary. To learn more, see the Understanding additional options section later in this article.
Note that you'll see an error that states One of the columns must have unique values if none of the tables selected for the relationship has unique values. At least one table in a relationship must have a distinct, unique list of key values, which is a common requirement for all relational database technologies. If you encounter that error, there are a couple ways to fix the issue: Use "Remove Duplicate Rows" to create a column with unique values.
The drawback to this approach is that you will lose information when duplicate rows are removed, and often a key row is duplicated for good reason. Add an intermediary table made of the list of distinct key values to the model, which will then be linked to both original columns in the relationship.
For more detailed information, see the blog post that discusses this in detail. Edit a relationship On the Home tab, click Manage Relationships.
In the Manage Relationships dialog, select the relationship, then click Edit. Configure additional options When you create or edit a relationship, you can configure additional options. By default, additional options are automatically configured based on a best guess. This can be different for each relationship based on the data in the columns. This means the column in one table can have more than one instance of a value, and the other related table, often know as the Lookup table, has only one instance of a value.
One to One 1: See the Understanding additional options section later in this article for more details about when to change cardinality. Cross filter direction Both - This is the most common, default direction.Abraham-Hicks 2016 When it's time to end your relationship(new)
We imported Hosts by copying it and pasting it into Excel, then formatted the data as a table. To add the Hosts table to the Data Model, we need to establish a relationship. In Excel, click the Hosts tab to make it the active sheet. This step adds the Hosts table to the Data Model. It also opens the Power Pivot add-in, which you use to perform the remaining steps in this task. Notice that the Power Pivot window shows all the tables in the model, including Hosts.
Create and manage relationships in Power BI Desktop - Power BI | Microsoft Docs
Click through a couple of tables. Use the slide bar to resize the diagram so that you can see all objects in the diagram. Notice that four tables are unrelated to the rest of the tables: You notice that both the Medals table and the Events table have a field called DisciplineEvent. Upon further inspection, you determine that the DisciplineEvent field in the Events table consists of unique, non-repeated values.
The DisciplineEvent field represents a unique combination of each Discipline and Event. In the Medals table, however, the DisciplineEvent field repeats many times. Create a relationship between the Medals table and the Events table.
A line appears between them, indicating a relationship has been established. Click the line that connects Events and Medals. The highlighted fields define the relationship, as shown in the following screen. To connect Hosts to the Data Model, we need a field with values that uniquely identify each row in the Hosts table. Then we can search our Data Model to see if that same data exists in another table. With Hosts selected, switch back to Data View.
Extend the Data Model using calculated columns To establish a relationship between the Hosts table and the Data Model, and thereby extend our Data Model to include the Hosts table, Hosts must have a field that uniquely identifies each row.
In addition, that field must correspond to a field in the Data Model. You can, however, create new columns by using calculated fields based on the existing data. By looking through the Hosts table, then looking at other Data Model tables, we find a good candidate for a unique field we could create in Hosts, and then associate with a table in the Data Model.
Both tables will require a new, calculated column in order to meet the requirements necessary to establish a relationship. In Hosts, we can create a unique calculated column by combining the Edition field the year of the Olympics event and the Season field Summer or Winter. In the Medals table there is also an Edition field and a Season field, so if we create a calculated column in each of those tables that combines the Edition and Season fields, we can establish a relationship between Hosts and Medals.
The goal is to create a calculated column in the Hosts table, and then in the Medals table, which can be used to establish a relationship between them.
Select the Hosts table in Power Pivot. Adjacent to the existing columns is an empty column titled Add Column. Power Pivot provides that column as a placeholder. There are many ways to add a new column to a table in Power Pivot, one of which is to simply select the empty column that has the title Add Column.
In the formula bar, type the following DAX formula. As you type, AutoComplete helps you type the fully qualified names of columns and tables, and lists the functions that are available. Use tab to select AutoComplete suggestions. You can also just click the column while typing your formula, and Power Pivot inserts the column name into your formula. Values are populated for all the rows in the calculated column. Such fields are called a primary key. You can rename any column by double-clicking it, or by right-clicking the column and choosing Rename Column.
When completed, the Hosts table in Power Pivot looks like the following screen. The Hosts table is ready.
Start by creating a new column in the Medals table, like we did for Hosts. Notice that Add Column is selected. This has the same effect as simply selecting Add Column. The Edition column in Medals has a different format than the Edition column in Hosts. Before we combine, or concatenate, the Edition column with the Season column to create the EditionID column, we need to create an intermediary field that gets Edition into the right format.
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In the formula bar above the table, type the following DAX formula. Values are populated for all the rows in the calculated column, based on the formula you entered. Rename the column by right-clicking CalculatedColumn1 and selecting Rename Column. Type Year, and then press Enter. When you created a new column, Power Pivot added another placeholder column called Add Column.
In the formula bar, type the following DAX formula and press Enter. Sort the column in ascending order. The Medals table in Power Pivot now looks like the following screen. Notice many values are repeated in the Medals table EditionID field. What is unique in the Medals table is each awarded medal. The unique identifier for each record in the Medals table, and its designated primary key, is the MedalKey field.
The next step is to create a relationship between Hosts and Medals. You can also switch between Grid view and Diagram view using the buttons at the bottom of the PowerView window, as shown in the following screen. Expand Hosts so you can view all of its fields. We created the EditionID column to act as the Hosts table primary key unique, non-repeated fieldand created an EditionID column in the Medals table to enable establishment of a relationship between them.
We need to find them both, and create a relationship. Power Pivot provides a Find feature on the ribbon, so you can search your Data Model for corresponding fields. Position the Hosts table so that it is next to Medals. Power Pivot creates a relationship between the tables based on the EditionID column, and draws a line between the two columns, indicating the relationship.
In this section, you learned a new technique for adding new columns, created a calculated column using DAX, and used that column to establish a new relationship between tables. You can also use the associated data to create additional PivotTables, PivotCharts, Power View reports, and much more. Create a hierarchy Most Data Models include data that is inherently hierarchical. Common examples include calendar data, geographical data, and product categories.
Creating hierarchies within Power Pivot is useful because you can drag one item to a report — the hierarchy — instead of having to assemble and order the same fields over and over. The Olympics data is also hierarchical.