Update mutation pattern in GraphQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a GraphQL mutation to update a user's name.

GraphQL

mutation UpdateUserName($id: ID!, $name: String!) {
  updateUser(id: $id, input: { name: [1] }) {
    id
    name
  }
}

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

A$name

Bid

C$id

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Using the field name 'name' instead of the variable '$name'.

Using the user ID variable instead of the name variable.

The variable $name is used to pass the new name value in the mutation input.

2fill in blank

medium

Complete the code to specify the mutation name correctly.

GraphQL

mutation [1]($id: ID!, $email: String!) {
  updateUser(id: $id, input: { email: $email }) {
    id
    email
  }
}

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

Aupdate_email

BUpdateUserEmail

CupdateUserEmail

DUpdate_Email

Attempts:

3 left

💡 Hint

Common Mistakes

Using snake_case or PascalCase for mutation names.

Starting mutation names with uppercase letters.

Mutation names typically use camelCase starting with a lowercase letter in GraphQL.

3fill in blank

hard

Fix the error in the mutation argument to correctly pass the user ID.

GraphQL

mutation updateUser($id: ID!, $name: String!) {
  updateUser(id: [1], input: { name: $name }) {
    id
    name
  }
}

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

A$id

Bname

C$name

Did

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the field name 'id' instead of the variable '$id'.

Passing the name variable instead of the ID variable.

The user ID must be passed as the variable $id to match the mutation parameter.

4fill in blank

hard

Fill both blanks to complete the mutation that updates a user's age and returns the updated age and name.

GraphQL

mutation [1]($id: ID!, $age: Int!) {
  updateUser(id: $id, input: { age: [2] }) {
    age
    name
  }
}

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

AupdateUserAge

B$age

C$name

Dage

Attempts:

3 left

💡 Hint

Common Mistakes

Using the field name 'age' instead of the variable '$age' in the input.

Using the wrong mutation name format.

The mutation name is updateUserAge and the age input uses the variable $age.

5fill in blank

hard

Fill all three blanks to write a mutation that updates a user's profile with name and email, and returns the id, name, and email.

GraphQL

mutation [1]($id: ID!, $name: String!, $email: String!) {
  updateUser(id: $id, input: { name: [2], email: [3] }) {
    id
    name
    email
  }
}

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

AupdateUserProfile

B$name

C$email

DuserProfileUpdate

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong mutation name.

Passing input fields without the dollar sign variables.

The mutation name is updateUserProfile. The input fields use variables $name and $email.

Practice

1. What is the main purpose of an update mutation in GraphQL?

easy

A. To create new data records

B. To change existing data by specifying an ID and new values

C. To delete data from the database

D. To fetch data without any changes

Solution

1. Step 1: Understand the role of update mutations

   Update mutations modify existing records by identifying them and applying new values.

2. Step 2: Differentiate from other mutation types

   Delete mutations remove data, create mutations add new data, and queries fetch data without changes.

3. Final Answer:

   To change existing data by specifying an ID and new values -> Option B

4. Quick Check:

   Update mutation = change existing data [OK]

Hint: Update mutations modify existing records by ID [OK]

Common Mistakes:

• Confusing update with create or delete mutations
• Thinking update fetches data without changes
• Assuming update creates new records

2. Which of the following is the correct syntax for an update mutation in GraphQL?

easy

A. mutation { updateUser(id: "123", input: {name: "Alice"}) { id name } }

B. mutation { createUser(id: "123", input: {name: "Alice"}) { id name } }

C. query { updateUser(id: "123", input: {name: "Alice"}) { id name } }

D. mutation { deleteUser(id: "123") { id name } }

Solution

1. Step 1: Identify the mutation keyword and operation

   Update mutations use the mutation keyword and specify the update operation with an ID and input object.

2. Step 2: Check the options for correct mutation syntax

   mutation { updateUser(id: "123", input: {name: "Alice"}) { id name } } uses mutation with updateUser and input fields correctly; others use wrong operation or query keyword.

3. Final Answer:

   mutation { updateUser(id: "123", input: {name: "Alice"}) { id name } } -> Option A

4. Quick Check:

   Update mutation syntax = mutation + update operation + input [OK]

Hint: Update mutations use 'mutation' keyword with update operation [OK]

Common Mistakes:

• Using 'query' instead of 'mutation'
• Using create or delete operation instead of update
• Missing input object for new values

3. Given this mutation:

mutation { updatePost(id: "5", input: {title: "New Title"}) { id title content } }

What will be the output if the post with ID 5 exists and has content "Old content"?

medium

A. { "data": { "updatePost": null } }

B. { "data": { "updatePost": { "id": "5", "title": "Old Title", "content": "Old content" } } }

C. { "data": { "updatePost": { "id": "5", "title": "New Title", "content": "Old content" } } }

D. Error: Post with ID 5 not found

Solution

1. Step 1: Understand the mutation effect

   The mutation updates the post with ID 5, changing only the title to "New Title" while keeping other fields unchanged.

2. Step 2: Predict the returned data

   The response includes the updated title and the unchanged content "Old content" along with the ID.

3. Final Answer:

   { "data": { "updatePost": { "id": "5", "title": "New Title", "content": "Old content" } } } -> Option C

4. Quick Check:

   Update mutation returns updated fields plus unchanged fields [OK]

Hint: Update changes specified fields, others remain same [OK]

Common Mistakes:

• Assuming all fields reset or become null
• Expecting error when post exists
• Ignoring unchanged fields in output

4. Identify the error in this update mutation:

mutation { updateUser(input: {name: "Bob"}) { id name } }

medium

A. Missing the ID argument to specify which user to update

B. Input object should be named 'data' instead of 'input'

C. Mutation keyword should be 'query' instead of 'mutation'

D. Cannot update the 'name' field

Solution

1. Step 1: Check required arguments for update mutation

   Update mutations require an ID to identify the record to update.

2. Step 2: Analyze the given mutation

   The mutation lacks the ID argument, so it cannot know which user to update.

3. Final Answer:

   Missing the ID argument to specify which user to update -> Option A

4. Quick Check:

   Update mutation must include ID argument [OK]

Hint: Always include ID to update specific record [OK]

Common Mistakes:

• Omitting the ID argument
• Confusing input object name
• Using 'query' instead of 'mutation'

5. You want to update a user's email and phone number but only if the phone number is provided. Which mutation pattern correctly handles this conditional update?

mutation UpdateUser($id: ID!, $email: String!, $phone: String) {
  updateUser(id: $id, input: {email: $email, phone: $phone}) {
    id
    email
    phone
  }
}

hard

A. Create separate mutations for email and phone updates

B. Always send phone field with empty string if no update needed

C. Use optional input fields and send null for phone if not updating

D. Remove phone field from input object when not updating

Solution

1. Step 1: Understand conditional updates in GraphQL

   To update only provided fields, omit fields not meant to be changed from the input object.

2. Step 2: Analyze options for handling optional phone

   Sending null or empty string may overwrite data; omitting the phone field avoids unintended changes.

3. Final Answer:

   Remove phone field from input object when not updating -> Option D

4. Quick Check:

   Omit fields to keep existing values unchanged [OK]

Hint: Omit fields to avoid overwriting unchanged data [OK]

Common Mistakes:

• Sending null overwrites existing data
• Using empty string instead of omitting field
• Creating unnecessary multiple mutations