Power BI Data Modeling: Why to Create Power BI Table Relationships in Data Model
Author: Anna Odrynska
Chief Strategy Officer at Alpha Serve
Published: March 3, 2023
Last Updated: April 30, 2024
Last Updated: April 30, 2024
Microsoft's Power BI is a powerful business intelligence tool. It equips analysts with the right tool with a simple interface to visualize and make sense of data. However, you must know about Power BI data modeling to make the most out of it.
This article will dive deep into Power BI data modeling and explain how to create and manage Power BI table relationships. We'll also look closer at Power BI Cardinality and Cross Filter Direction. Lastly, we'll discuss the benefits Power BI Connector brings to Power BI Data Modeling.
This article will dive deep into Power BI data modeling and explain how to create and manage Power BI table relationships. We'll also look closer at Power BI Cardinality and Cross Filter Direction. Lastly, we'll discuss the benefits Power BI Connector brings to Power BI Data Modeling.
Table of Contents:
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What is Power BI Data Modeling
Data Modeling is combining two or more tables and creating relationships. Doing so allows you to work on multiple relationship tables like one. It also reduces the complexity of working with massive datasets as you can identify and connect the required fields.
Power BI data modeling is using Power BI to create data models. It provides data admins and analysts the tools to build seamless table relationships. As a result, you can make interactive, complex, insightful visuals and reports with refined data.
In short, Power BI eases the need to store all necessary data in a single table. Instead, you can connect fields and tables to create relationships with a common column, allowing you to create an abstract table containing all necessary data for analyzing and report creation.
Power BI data modeling is using Power BI to create data models. It provides data admins and analysts the tools to build seamless table relationships. As a result, you can make interactive, complex, insightful visuals and reports with refined data.
In short, Power BI eases the need to store all necessary data in a single table. Instead, you can connect fields and tables to create relationships with a common column, allowing you to create an abstract table containing all necessary data for analyzing and report creation.
Why Do You Need Data Relationships in Power BI
Businesses generate tons of data every single day. The generated data can be from different departments, storing specific information for various purposes. In Power BI, you can create data relationships between tables and fields, allowing you to create insightful reports.
To better understand why you need database relationships in Power BI, let's look at the points below:
- Data relationships give you a clear and concise view of your data.
- If your report depends on multiple tables, you can easily query them. This way, you can identify correlations and trends between different datasets.
- Filters can propagate if there is a deterministic relationship path to follow. It means filters can work on multiple tables. To make the most out of filters, you must create relationships between tables to drill down specific parts of data.
- Data relationships enable analysts to connect data from multiple sources and create relationships between tables.
- By creating relationships between tables, you also reduce query complexities while making datasets easier to work with.
- Complex reports depend on multiple datasets. With relationships in Power BI, you can create complex visuals and reports and benefit from deeper data insights.
- Users can also use relevant DAX functions to modify or disable these relationships.
How to Create Relationships in Power BI
Creating relationships in Power BI is easy. That's because it offers access to Autodetect feature for table relationships. However, you may find it limiting in some scenarios. To overcome it, you can always create table relationships manually, giving you more control over your data sets.
Create Power BI Table Relationships Manually
Create Power BI Table Relationships Manually
Power BI lets you create table relationships manually. Here, the user must manually create all the relationships. Their cardinality, active properties, and cross-filter direction are automatically set during creation, but users can edit them as required. Even though this approach is time-consuming, it gives users the ability to have more control over which data to connect, especially when working with complex datasets.
Go to the Modeling tab and select Power BI Manage relationships. From there, select New. In the Create Relationship dialog box, select a table and the preferred column for the relationship. Next, choose the second table and a column here to make a relationship. Here, Power BI handles cross-filter detection and cardinality. It also sets the relationship active.
You can also check for Power BI data models' accuracy and reliability during the manual process. Again, this is because users need to be mindful of the relationships they create.
Go to the Modeling tab and select Power BI Manage relationships. From there, select New. In the Create Relationship dialog box, select a table and the preferred column for the relationship. Next, choose the second table and a column here to make a relationship. Here, Power BI handles cross-filter detection and cardinality. It also sets the relationship active.
You can also check for Power BI data models' accuracy and reliability during the manual process. Again, this is because users need to be mindful of the relationships they create.
Use Autodetect for Auto-Generated Relationships
Use Autodetect for Auto-Generated Relationships
Power BI is smart enough to auto-detect relationships between tables. It helps create a useful Power BI data model without external user interference. It also comes in handy for complex datasets containing multiple tables. By default, the autodetect feature takes care of active properties, cross-channel bearing, and cardinality.
To use it, go to the Modeling tab, select Manage relationships, and Autodetect.
Under the hood, Power BI uses detailed data profiling techniques to learn about table contents. Then, it analyzes them and identifies common columns automatically. Once identified, it creates the relationships between tables.
Apart from saving time and effort by automatically generating table relationships, users can also use the autodetect functionality to find data issues. For example, if the auto-generated relationship fails, it might indicate a problem with the data.
Finally, you must know that auto-detect relationships are not always accurate or perfect. Sometimes, the relationships might need to be corrected and reflect the underlying data. And in other cases, Power BI can fail to automatically create table relationships even when a relationship is present in the data. In any case, the user must manually check the tables and find and resolve the issue.
To learn more about creating Power BI relationships manually or automatically, read How to create and manage relationships in Power BI Desktop.
To use it, go to the Modeling tab, select Manage relationships, and Autodetect.
Under the hood, Power BI uses detailed data profiling techniques to learn about table contents. Then, it analyzes them and identifies common columns automatically. Once identified, it creates the relationships between tables.
Apart from saving time and effort by automatically generating table relationships, users can also use the autodetect functionality to find data issues. For example, if the auto-generated relationship fails, it might indicate a problem with the data.
Finally, you must know that auto-detect relationships are not always accurate or perfect. Sometimes, the relationships might need to be corrected and reflect the underlying data. And in other cases, Power BI can fail to automatically create table relationships even when a relationship is present in the data. In any case, the user must manually check the tables and find and resolve the issue.
To learn more about creating Power BI relationships manually or automatically, read How to create and manage relationships in Power BI Desktop.
How to Manage Relationships in Power BI
Even though Power BI automates table relationships, you must ensure they're correct. It's essential to use cardinality and cross-filter detection features. Let's discuss them below.
Power BI Cardinality
Power BI Cardinality
In each model, relationships are defined by their cardinality type. Power BI relationships have many cardinalities.
These include:
- One-to-one (1:1)
- One to many (1:*)
- Many to one (*:1)
- Many to many (*:*)
The one-to-one cardinality connects one item from a table to another item from another table. It is a one-to-one relationship and should not be used as it can lead to models with inadequate data. That's why one-to-one is rarely used.
However, one-to-many is a popular relationship, connecting one column from a table to different columns of a second table. It improves data visibility and gives you the ability to gain specific insights. For example, you can use it to gain insights into your quarter's inventory or sales.
Next comes the many-to-one relationship. It is the opposite of one-to-many. Technically, several items from the second table connect with one item from the first, creating a many-to-one relationship. As a data analyst, you can shift between "one-to-many" to "many-to-one" to better understand data.
Lastly, we have many-to-many relationships. It lets you create complex relationship models. For example, one or two columns in a table connect with one or more items on another table. However, it can be helpful when working with massive data sets and help you refine them for usability.
However, one-to-many is a popular relationship, connecting one column from a table to different columns of a second table. It improves data visibility and gives you the ability to gain specific insights. For example, you can use it to gain insights into your quarter's inventory or sales.
Next comes the many-to-one relationship. It is the opposite of one-to-many. Technically, several items from the second table connect with one item from the first, creating a many-to-one relationship. As a data analyst, you can shift between "one-to-many" to "many-to-one" to better understand data.
Lastly, we have many-to-many relationships. It lets you create complex relationship models. For example, one or two columns in a table connect with one or more items on another table. However, it can be helpful when working with massive data sets and help you refine them for usability.
Power BI Cross Filter Direction
Power BI Cross Filter Direction
Each Power BI cardinality also has a cross-filter direction. This cross-filter defines the model relationship and determines the order in which filters propagate.
For example, the one-to-many cardinality type can have single (direction) or both (direction) cross-filter options. So if you're using one-to-one, you can access both directions, but not in a single direction. It is similar to Power BI many to many, where you can set single cross-filter options from one table to another and access both.
If you set the cross-filter direction to “both”, you can access the Row-level security (RLS) rule. Also, you can use model calculation through the Crossfilter function to disable or modify the cross-filter direction.
For example, the one-to-many cardinality type can have single (direction) or both (direction) cross-filter options. So if you're using one-to-one, you can access both directions, but not in a single direction. It is similar to Power BI many to many, where you can set single cross-filter options from one table to another and access both.
If you set the cross-filter direction to “both”, you can access the Row-level security (RLS) rule. Also, you can use model calculation through the Crossfilter function to disable or modify the cross-filter direction.
How Power BI Connector Can Benefit Power BI Data Modeling
Power BI is a powerful tool. However, it still has space to improve. One such feature is proper data importing and filtering. And that's where BI Connector comes in. Its custom-built solution lets you connect data sources to BI, providing convenient data export. It also provides flexibility and removes any need to follow complicated steps to export custom fields.
However, the most crucial feature of the Power BI connector is the ability to simplify relationship creation among tables. Alongside removing complexity around relationship creation between multiple tables, it also ensures no data duplication or inconsistency.
So, how Power BI Connector helps you overcome these challenges? Let's take the Power BI Connector for Jira as an example. It enables connecting Jira with Power BI. You can also use it to automate the correct construction of relationships between tables, including Jira custom fields and supported add-ons. All you need to do is select what Jira tables and fields you want to include in your report by clicking on checkboxes while creating data sources.
Once done, Power BI Connector for Jira will take over and automatically build relationships between tables. Finally, you can preview the data schema to ensure all relationships are correct.
However, the most crucial feature of the Power BI connector is the ability to simplify relationship creation among tables. Alongside removing complexity around relationship creation between multiple tables, it also ensures no data duplication or inconsistency.
So, how Power BI Connector helps you overcome these challenges? Let's take the Power BI Connector for Jira as an example. It enables connecting Jira with Power BI. You can also use it to automate the correct construction of relationships between tables, including Jira custom fields and supported add-ons. All you need to do is select what Jira tables and fields you want to include in your report by clicking on checkboxes while creating data sources.
Once done, Power BI Connector for Jira will take over and automatically build relationships between tables. Finally, you can preview the data schema to ensure all relationships are correct.
Conclusion
Conclusion
Overall, Power BI Connector simplifies data import and helps you automate and create a relationship between tables.
In short, the benefits include:
So, how are you going to approach Power BI data modeling? Share the article with a comment to let us know your thoughts.
In short, the benefits include:
- Add tables from supported add-ons
- Include custom tables and fields
- Automate data relationships between multiple tables
So, how are you going to approach Power BI data modeling? Share the article with a comment to let us know your thoughts.
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