OData and REST API connections in Power BI - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to connect Power BI to an OData feed URL.

Power BI

let
    Source = OData.Feed("[1]")
in
    Source

Drag options to blanks, or click blank then click option'

Ahttp://localhost:8080/api/data

BC:/Users/Documents/data.csv

Cftp://example.com/data

Dhttps://services.odata.org/V4/OData/OData.svc/

Attempts:

3 left

💡 Hint

Common Mistakes

Using a local file path instead of a URL.

Using an FTP URL which is not supported by OData.Feed.

Using a REST API URL that is not an OData service.

The OData.Feed function requires a valid OData service URL to connect and retrieve data.

2fill in blank

medium

Complete the code to add HTTP headers when connecting to a REST API in Power BI.

Power BI

let
    Source = Json.Document(Web.Contents("https://api.example.com/data", [Headers=[[1]]]))
in
    Source

Drag options to blanks, or click blank then click option'

A#"Authorization" = "Bearer token123"

B[Authorization = "Bearer token123"]

C#"Content-Type" = "application/json"

D[Content-Type = "application/json"]

Attempts:

3 left

💡 Hint

Common Mistakes

Using curly braces {} instead of square brackets [] for headers.

Using colon instead of equals sign for key-value pairs.

Passing headers as a list instead of a record.

Headers in Web.Contents must be passed as a record inside a record, using square brackets and equals signs.

3fill in blank

hard

Fix the error in the Power Query code to correctly parse JSON from a REST API.

Power BI

let
    Source = Web.Contents("https://api.example.com/data"),
    JsonData = Json.Document([1])
in
    JsonData

Drag options to blanks, or click blank then click option'

ASource()

BJson.Document

CSource

DWeb.Contents

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the function Web.Contents instead of its result.

Calling Source as a function with parentheses.

Passing Json.Document inside itself.

The Json.Document function needs the binary content from Web.Contents, which is stored in the variable Source.

4fill in blank

hard

Fill both blanks to filter OData feed data for products with Price greater than 100.

Power BI

let
    Source = OData.Feed("https://services.odata.org/V4/OData/OData.svc/"),
    Filtered = Table.SelectRows(Source, each [1] > [2])
in
    Filtered

Drag options to blanks, or click blank then click option'

A[Price]

B100

C50

D[Quantity]

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong column name like Quantity.

Using a smaller number like 50 instead of 100.

Not using square brackets around the column name.

To filter rows where the Price column is greater than 100, use [Price] and the number 100.

5fill in blank

hard

Fill all three blanks to create a custom header and query parameter for a REST API call in Power BI.

Power BI

let
    Source = Web.Contents(
        "https://api.example.com/data",
        [
            Headers = [[1]],
            Query = [[2] = [3]]
        ]
    )
in
    Source

Drag options to blanks, or click blank then click option'

A#"Authorization" = "Bearer abc123"

Bfilter

C"status eq 'active'"

D#"Content-Type" = "application/json"

Attempts:

3 left

💡 Hint

Common Mistakes

Using curly braces {} instead of square brackets [] for headers.

Not quoting the query parameter key and value correctly.

Mixing up headers and query parameters.

The Headers record must include the Authorization token. The Query record uses the key "filter" and the value "status eq 'active'" to filter data.

Practice

1. What is the main advantage of using an OData connection in Power BI compared to a generic REST API?

easy

A. It cannot refresh data automatically.

B. It requires manual coding for every data request.

C. It only works with Excel files.

D. It provides a standardized query language and easier data filtering.

Solution

1. Step 1: Understand OData protocol features

   OData supports standardized query options like filtering, sorting, and paging directly in the URL.

2. Step 2: Compare with REST API flexibility

   REST APIs are flexible but often require custom query parameters and manual handling of data requests.

3. Final Answer:

   It provides a standardized query language and easier data filtering. -> Option D

4. Quick Check:

   OData = Standardized queries [OK]

Hint: OData uses standard queries; REST APIs need custom calls [OK]

Common Mistakes:

• Thinking OData only works with Excel
• Assuming REST APIs auto-refresh data
• Believing OData requires manual coding

2. Which Power Query M function is used to connect to a REST API endpoint in Power BI?

easy

A. OData.Feed()

B. Web.Contents()

C. Csv.Document()

D. Excel.Workbook()

Solution

1. Step 1: Identify function for REST API calls

   The Web.Contents() function fetches data from any web URL, including REST APIs.

2. Step 2: Differentiate from OData function

   OData.Feed() is specific for OData sources, not generic REST APIs.

3. Final Answer:

   Web.Contents() -> Option B

4. Quick Check:

   REST API = Web.Contents() [OK]

Hint: Use Web.Contents() for REST API URLs [OK]

Common Mistakes:

• Using OData.Feed() for REST APIs
• Confusing CSV import with API calls
• Trying Excel.Workbook() for web data

3. Given this Power Query M code snippet connecting to an OData feed:

let
  Source = OData.Feed("https://services.odata.org/V4/Northwind/Northwind.svc/Products"),
  Filtered = Table.SelectRows(Source, each [CategoryID] = 1)
in
  Filtered

What will be the result?

medium

A. An empty table because CategoryID is not a valid column.

B. An error because OData.Feed cannot filter data.

C. A table of products where CategoryID equals 1.

D. A list of all categories instead of products.

Solution

1. Step 1: Understand OData.Feed output

   The OData.Feed() function returns a table of products from the OData service.

2. Step 2: Analyze filtering step

   Table.SelectRows() filters rows where CategoryID equals 1, which is valid for this dataset.

3. Final Answer:

   A table of products where CategoryID equals 1. -> Option C

4. Quick Check:

   Filter by CategoryID=1 = filtered product table [OK]

Hint: OData.Feed returns tables; filter with Table.SelectRows() [OK]

Common Mistakes:

• Assuming OData.Feed cannot filter
• Confusing products with categories
• Thinking CategoryID column is missing

4. You wrote this Power Query M code to get data from a REST API:

let
  Source = Web.Contents("https://api.example.com/data"),
  Json = Json.Document(Source),
  Table = Table.FromList(Json, Splitter.SplitByNothing())
in
  Table

But you get an error saying "Expression.Error: We cannot convert the value to a table." What is the likely cause?

medium

A. The JSON returned is an object, not a list, so Table.FromList fails.

B. Web.Contents() cannot fetch JSON data.

C. Json.Document() only works with XML data.

D. Splitter.SplitByNothing() is not a valid function.

Solution

1. Step 1: Check JSON structure expected

   Table.FromList() expects a list, but if JSON is an object (record), it cannot convert directly.

2. Step 2: Understand error cause

   The error means the JSON is not a list but an object, so conversion fails.

3. Final Answer:

   The JSON returned is an object, not a list, so Table.FromList fails. -> Option A

4. Quick Check:

   JSON object ≠ list causes conversion error [OK]

Hint: Check if JSON is list or object before Table.FromList() [OK]

Common Mistakes:

• Thinking Web.Contents() can't get JSON
• Assuming Json.Document() only parses XML
• Believing Splitter.SplitByNothing() is invalid

5. You want to combine data from an OData feed and a REST API in Power BI. The OData feed provides product details, and the REST API returns live stock levels as JSON. Which approach is best to create a unified table for reporting?

hard

A. Use OData.Feed() to get products, Web.Contents() + Json.Document() for stock, then merge tables in Power Query.

B. Use only OData.Feed() for both sources since it supports all APIs.

C. Import REST API JSON as CSV and append to OData feed table directly.

D. Load both sources separately and create relationships in the data model without merging.

Solution

1. Step 1: Connect to each data source appropriately

   Use OData.Feed() for the OData product details and Web.Contents() with Json.Document() to parse REST API stock JSON.

2. Step 2: Combine data in Power Query

   Merge the two tables on product ID to create a unified table before loading into the report.

3. Final Answer:

   Use OData.Feed() to get products, Web.Contents() + Json.Document() for stock, then merge tables in Power Query. -> Option A

4. Quick Check:

   Combine sources with correct connectors and merge [OK]

Hint: Use correct connectors per source, then merge in Power Query [OK]

Common Mistakes:

• Trying to use OData.Feed() for REST API JSON
• Appending JSON as CSV without parsing
• Not merging data, just relating tables