Power BI Data Connection and Transformation

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Questions and Answers

What is the primary purpose of connecting to a data source in Power BI Desktop?

To establish a connection for data import (correct)

To perform data analysis without loading data

To visualize the data directly in the report

To create a data model from unstructured data

Which feature allows developers to manage data from multiple sources in Power BI Desktop?

Power Query Editor (correct)

Report Builder

Visual Studio Integration

Data Management Studio

During the data connection process, what occurs after selecting a data source on the Get Data screen?

Application settings are reconfigured

The Navigator screen shows the available tables (correct)

The data is automatically visualized

The metadata of the data source is displayed

What can a developer do after combining queries from multiple data sources in Power BI Desktop?

Create a unified data model for visualizations (C) Signup and view all the answers

What is the first step a developer should take when starting a new file in Power BI Desktop?

Connect to a data source using the Get data button (B) Signup and view all the answers

What must be done before using data from different sources to create visualizations in Power BI?

Perform data modeling on the combined data (C) Signup and view all the answers

Which of the following is NOT a feature of Power BI when connecting to data sources?

Automatic correction of data inconsistencies (C) Signup and view all the answers

What option is available to developers in Power BI Desktop after the initial connection to a data source?

Access an additional data source and add it to the report (A) Signup and view all the answers

What is the main purpose of data modeling in Power BI?

To optimize data for effective visualization in reports. (C) Signup and view all the answers

Which action is NOT considered a part of data transformation in Power Query?

Backing up original data sources. (C) Signup and view all the answers

When a developer changes the data type of a column in Power Query, what happens to the original data in its source?

The original data remains unchanged. (D) Signup and view all the answers

How can a developer undo a previously applied data transformation in Power Query?

By deleting the transformation from the Applied Steps list. (C) Signup and view all the answers

What is the distinction between merging and appending queries in Power BI?

Merging combines columns, while appending adds new rows. (D) Signup and view all the answers

Which of the following tasks can be performed to modify data types in Power Query?

Using the Change Type option from the context menu. (B) Signup and view all the answers

What visual indicator shows that a column's data type has been changed to number in Power Query?

The number '123' tag in the column header. (C) Signup and view all the answers

If a developer needs to use state abbreviations instead of full state names, what action might they take during data transformation?

They will merge another data source containing both names and abbreviations. (A) Signup and view all the answers

In Power Query, which action would a developer take to remove columns that are no longer needed?

Select the columns and use the Manage Columns > Remove Command. (B) Signup and view all the answers

What is indicated by the 'table' label in the merged query column after performing a merge?

It shows that the merged query contains multiple columns. (A) Signup and view all the answers

After completing data modeling, how does a developer incorporate the modeled data into a report in Power BI?

By selecting Close & Apply in the ribbon’s Close group. (D) Signup and view all the answers

What must a developer do to ensure columns are named correctly after importing data?

Right-click each column and rename them if necessary. (D) Signup and view all the answers

Which function is primarily used in Power Query to combine data from different sources?

Merge Queries. (A) Signup and view all the answers

Study Notes

Connecting to and Consuming Data in Power BI

Power BI allows connecting to various data sources
Power BI Desktop allows combining data from multiple sources
To start, click "Get Data" to access the "Get Data" screen
Select data sources (e.g., web pages), and provide necessary credentials
Power BI evaluates the data sources and displays available tables (Navigator screen)
Load tables into the Fields pane (Report view)
Repeat for additional sources

Transforming Data with Power Query

Data modeling/shaping/transforming prepares data for visualizations
Data modifications do not affect original data
Modifying Data Types:
Change column types (e.g., text to whole number) in the Power Query Editor
Right-click or use the drop-down menu
Modifications are recorded (Applied Steps) for potential reversal
Removing Rows/Columns:
Remove unneeded columns/rows using "Manage Columns > Remove Columns"
Renaming Elements:
Use first row as headers or manually rename to match other data sources
Combining Queries:
Merge: Adds columns from one source to another.
Append: Adds rows from one source to another.

Merging Queries

Use "Combine > Merge Queries" to merge queries
Specify columns to match during merging (e.g., "State" and "State Name" columns)
The merged data appears as a single column with the merged data contained
Use the "Expand" button to show expanded columns
Select specific columns needed for the merged query—deselecting unneeded columns.
Clicking "Close & Apply" adds the model to Power BI Desktop and prepares the visualization.

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Description

This quiz covers the essential processes of connecting to data sources and transforming that data in Power BI. Learn how to use Power Query to prepare your data for visualizations and understand how to modify data types, remove unnecessary elements, and manage your data effectively. Test your knowledge on these key functionalities of Power BI.