This is the first post in a three-part series exploring the mechanics of Materialized Lake Views. The goal is to help you understand how they work and whether they make sense for your environment. What they are, when they help, and when they fall short.
High-level comparison
If you haven’t looked into Fabric notebooks for data visualization, the table below offers a high-level comparison to Power BI reports. There are edge cases where you could do something successfully in either tool, but generally certain personas and use cases lean towards one or the other.| Feature | Power BI | Fabric Notebooks |
|---|---|---|
| Purpose | Designed for interactive dashboards and reports | Used for data exploration, transformation, and advanced analytics |
| Visuals | Drag-and-drop visuals, prebuilt charts | Code-based visuals using Python (Matplotlib, Seaborn) or Spark libraries |
| Interactivity | Highly interactive, slicers, drill-throughs | Limited interactivity; static charts unless using specific libraries |
| Best For | Business reporting and storytelling | Data exploration, debugging, machine learning/AI |
Where do notebooks shine?
Notebooks are not usually the best interface for business dashboards and scorecards, but there are other situations where they might be better than a Power BI report:- Data dumps (can save to OneLake or blob storage when output contains a lot of rows)
- Detailed static chart images
- Maps (interactive or static)
- Highly customized charts and uncommon chart types
- High-density visuals
- Adding advanced statistics, AI, or ML on top of a base dataset before visualization
Interactivity
Python visuals can offer some interactivity, depending on the library. It is often only within one visual. For instance, you might have a drop-down for selecting a category which filters a bar chart. Or you might use a lasso tool to select an area of a map. What is less common is to create a set of multiple charts in a single output that all interact with each other. That is one area where Power BI shines and requires little to no effort, since the default is for visuals to interact with all other visuals on the report page.Remember your audience
While the visualizations produced by a notebook may be great for your audience, the notebook interface itself might not be ideal for consumption. Data engineers are often used to notebooks in other contexts, but the average business analyst might not want to use a notebook. This may lead to creating the visualization in one tool and consuming it in another. You’ll have to examine the context to and use case to decide if that is appropriate.Could a notebook really be easier than a drag-and-drop interface?
If writing Python code seems unattainable, a notebook might not be for you. But I’d like to share a couple of thoughts about what has made Python easier for me.The libraries
After learning about the concept of a nullity matrix, I set out to create one in Power BI for a Workout Wednesday challenge. After experimenting with core visuals and not liking the results, I switched to Deneb. I struggled a bit to get what I needed in Deneb and after an hour or so, I sought out help. The Deneb visual ultimately worked fine, but it was a lot of effort to get there. There is a free library to do this in Python. Once you have a DataFrame with the data you want to include, it’s two lines of code to create the visual.AI Coding Assistants
With AI assistants to help us write Python code, the barrier to getting our desired visual output in a notebook is possibly lower than ever. You can integrate AI assistants like GitHub Copilot or Claude Code into VS Code to have a more seamless development experience outside of a browser, if you prefer. Just be sure that your use of AI coding assistants meets any organizational and/or personal requirements around information security and intellectual property.More posts on data viz in notebooks
I’ve planned at least a couple more posts to help people get started using notebooks for data visualization. Stay tuned! The post Data Viz in Fabric Notebooks first appeared on Data Savvy.Code walkthrough
If you aren’t using an environment with Semantic Link Labs already installed, you must do that first as shown below.%pip install semantic-link-labs Here I import and alias the report module from Semantic Link Labs as well as pandas. # Imports
import sempy_labs as labs
from sempy_labs import report
import pandas as pd Next I need to create a report wrapper for the report in which I want to review the bookmarks. var_rpt = '<insert item GUID here>'
var_ws = '<insert workspace GUID here>'
var_rptw = labs.report.ReportWrapper(
report=var_rpt, workspace=var_ws,readonly=False
) The main function used here is the Semantic Link Labs list_bookmarks function, which returns a list of all bookmarks in the selected report. The list_bookmarks function returns a DataFrame with the following columns. df_bookmarks = var_rptw.list_bookmarks()
display(df_bookmarks) Combining list_bookmarks and list_visuals
What we see in the results above is a good start, but we need to add more information about the visuals referenced by the bookmarks. We can use thelist_visuals function to get more info on each visual and then merge (join) the bookmark and visual data together for a more complete picture. df_visuals = var_rptw.list_visuals()
df_visuals = df_visuals[['Page Name', 'Visual Name', 'Display Type',
'X', 'Y', 'Z', 'Width', 'Data Visual']]
df_bookmarks = var_rptw.list_bookmarks()
df_bookmarkvisuals = pd.merge(df_bookmarks, df_visuals,
left_on='Visual Name',
right_on='Visual Name', how='inner')
df_bookmarkvisuals = df_bookmarkvisuals.drop(columns='Page Name_y')
df_bookmarkvisuals = df_bookmarkvisuals.rename(
columns={'Page Name_x': 'Page Name'})
var_newcolumnorder = ['Bookmark Display Name', 'Bookmark Name',
'Page Display Name', 'Page Name', 'Visual Name',
'Display Type', 'Visual Hidden', 'Data Visual',
'X', 'Y', 'Z', 'Width']
df_bookmarkvisuals = df_bookmarkvisuals[var_newcolumnorder]
df_bookmarkvisuals = df_bookmarkvisuals.sort_values(
by=['Bookmark Display Name', 'Display Type', 'X', 'Y'])
display(df_bookmarkvisuals) First, I obtained the list of all visuals in the report. Then I narrowed down the column list so I only kept what was helpful for this use case. Then I got the list of bookmarks. I merged the visuals and bookmarks by performing and inner join on the Visual Name (which is really the unique GUID for the visual). After merging, I dropped the Page Name column that came from the bookmarks DataFrame and renamed the Page Name column that came from the visuals DataFrame. Then I reordered the columns to make it easier to use the final table. Finally, I sorted the values by bookmark, visual type, and then the x and y coordinates of the visual. That gives me the following table. What’s Missing?
While we can infer some of the configured properties of a bookmark based upon what is returned here, it would be nice to have it explicitly returned. When we look at the JSON that defines the bookmark, we can see:- the bookmark display name (the name we see in the bookmarks pane)
- the bookmark name (the GUID for the bookmark)
- the page name (the GUID for the page)
- the GUIDs for the target visuals
- whether data is included in the bookmark
- if data is included, the filter expressions
- if data is included, slicer type and state
- if data is included, the sort order for a visual
- if data is included, drill location
- if data is included, the spotlight mode of a visual
More posts about Semantic Link Labs
So far, I’ve been exploring the report and admin subpackages of Semantic Link Labs. Below are some other blog posts I’ve written about them. Check Power BI report interactions with Semantic Link Labs Finding fields used in a Power BI report in PBIR format with Semantic Link Labs Get Power BI Report Viewing History using Semantic Link Labs Modify Power BI page visibility and active status with Semantic Link Labs Enjoy! The post Check Power BI Bookmarks with Semantic Link Labs first appeared on Data Savvy.It can be tedious to check what visual interactions have been configured in a Power BI report. If you have a lot of bookmarks, this becomes even more important. If you do this manually, you have to turn on Edit Interactions and select each visual to see what interactions it is emitting to the other visuals on the page.
But there is a better way!
Listing visual interactions
You can use a a bit of Python in a Fabric notebook and the Semantic Link Labs library to return the list of modified interactions in a DataFrame. I take it one step further and also check for visuals that are not the target of any modified interactions.
For this to be useful, you have to understand that the default interactions are to cross-highlight or cross-filter where available. For instance, if you have a column chart that shows average student grades by subject and a bar chart that shows average grade by student, when you select the Science subject on the column chart, it will cross-highlight the bar chart so you can see how the student’s science grade compares to their total average. If you don’t like that interaction, you can change it. You can make it filter so you only see the science grade without the total in the background. Or you can configure it so there is no interaction and the bar chart is not cross-filtered or cross-highlighted.
The report definition is in JSON, and if you change no interactions from the default, interactions will not all be specifically listed. But if we change an interaction, we would see that change in the JSON.
Code walkthrough
If you aren’t using an environment with Semantic Link Labs already installed, you must do that first as shown below..
%pip install semantic-link-labs Here I import and alias the report module from Semantic Link Labs as well as pandas.
# Imports
import sempy_labs as labs
from sempy_labs import report
import pandas as pd Next I need to create a report wrapper for the report in which I want to review the interactions.
var_rpt = '<insert item GUID here>'
var_ws = '<insert workspace GUID here>'
var_rptw = labs.report.ReportWrapper(
report=var_rpt, workspace=var_ws,readonly=False
)
The main function used here is the Semantic Link Labs list_visual_interactions function, which gets the list of modified interactions.
var_rptw.list_visual_interactions() If you just use that function, you will get a DataFrame with the following columns.
Pages have display names, but visuals don’t. The title we see on visuals in Power BI Desktop is just a property and is not returned by this function. So if you know your report well, you might be able to determine what things are by the GUID (or use Visual Studio Code to view the JSON and locate the visual, but we can make this better with a little more code.
The list_visuals function provides more info about each visual, so if we merge (join) the dataframes containing the list of visuals and the list of modified interactions, we get something more useful.
var_reportname = labs.resolve_report_name(
var_rpt, workspace=var_ws
)
df_visuals = var_rptw.list_visuals()
df_visuals = df_visuals[[
'Page Name', 'Visual Name', 'Display Type', 'X', 'Y', 'Z', 'Width',
'Data Visual'
]]
df_interactions = var_rptw.list_visual_interactions()
df_visualinteractions1 = pd.merge(
df_interactions, df_visuals, left_on='Source Visual Name',
right_on='Visual Name', how='inner'
)
df_visualinteractions = pd.merge(
df_visualinteractions1, df_visuals, left_on='Target Visual Name',
right_on='Visual Name', how='inner'
)
df_visualinteractions = df_visualinteractions.drop(
columns=[
'Page Name_y', 'Visual Name_x', 'Data Visual_x', 'Page Name_x',
'Page Name_y', 'Z_x', 'Z_y', 'Visual Name_y'
]
)
df_visualinteractions = df_visualinteractions.rename(
columns={
'Display Type_x': 'Source Display Type', 'X_x': 'Source X',
'Y_x': 'Source Y', 'Width_x': 'Source Width',
'Display Type_y': 'Target Display Type', 'X_y': 'Target X',
'Y_y': 'Target Y', 'Width_y': 'Target Width',
'Data Visual_y': 'Target Is Data Visual',
'Type': 'Interaction Type'
}
)
var_newcolumnorder = [
'Page Display Name', 'Page Name', 'Interaction Type',
'Source Visual Name', 'Source Display Type', 'Source X', 'Source Y',
'Source Width', 'Target Visual Name', 'Target Display Type',
'Target Is Data Visual', 'Target X', 'Target Y', 'Target Width'
]
df_visualinteractions = df_visualinteractions[var_newcolumnorder]
df_visualinteractions = df_visualinteractions.sort_values(
by=['Page Display Name', 'Source Visual Name', 'Interaction Type']
)
display(df_visualinteractions) I narrowed down the column list for the visuals to only the ones I felt were helpful. The list of interactions contains a source visual (the visual emitting the interaction) and a target visual (the visual receiving the interaction). I merge the visual interactions with the visuals twice, so we can get info on both the source and target visuals. After merging, I dropped some columns and renamed others, then reordered the remaining columns to make it easier to understand. And finally, I sorted the values by page, then visual, then interaction type.
This results in the following table.
Now I can see what page the visuals are on, which type of interaction they have, what type of visual is used for the source and target, and where the source and target are located on the page.
I can also check which visuals have no modified interactions.
df_nochangedinteractions = df_visuals[
~df_visuals['Visual Name'].isin(
df_visualinteractions['Target Visual Name']
)
]
print(
'The following visuals are not the target of any modified '
'interactions:'
)
display(df_nochangedinteractions) Here, I take the full list of visuals and return any visual that is not listed in the target visuals in the table above. This returns the following table.
In my report, which uses the default size (1280 x 720), I have a large bar chart that is somewhat near the top of the page and about 1/3 of the way into the page. All the interactions of other visuals with this bar chart use the default interaction settings.
And if I run this last line of code, I can validate that by interacting with the report directly in my notebook.
#View the report to visually confirm the interactions
report.launch_report(report=var_reportname, workspace=var_ws) This adds a report viewer window containing the fully interactive report in the cell results area. By interacting with the report, I can confirm that I have turned off all interactions from the bar chart to other visuals.
More posts about Semantic Link Labs
So far, I’ve been exploring the report and admin subpackages of Semantic Link Labs. Below are some other blog posts I’ve written about them.
Finding fields used in a Power BI report in PBIR format with Semantic Link Labs
Get Power BI Report Viewing History using Semantic Link Labs
Modify Power BI page visibility and active status with Semantic Link Labs
Happy reading!
The post Check Power BI report interactions with Semantic Link Labs first appeared on Data Savvy.