Inserting and querying data in Supabase - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to insert a new row into the 'users' table.

Supabase

const { data, error } = await supabase.from('users').[1]({ name: 'Alice', age: 30 })

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

Aupdate

Bdelete

Cinsert

Dselect

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'select' instead of 'insert' to add data.

Using 'update' when trying to add new rows.

The insert method is used to add new rows to a table in Supabase.

2fill in blank

medium

Complete the code to select all rows from the 'products' table.

Supabase

const { data, error } = await supabase.from('products').[1]('*')

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

Ainsert

Bselect

Cupdate

Ddelete

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'insert' when trying to get data.

Forgetting to specify columns or using wrong method.

The select method retrieves data from a table. Using '*' selects all columns.

3fill in blank

hard

Fix the error in the code to update the 'age' of user with id 5.

Supabase

const { data, error } = await supabase.from('users').[1]({ age: 31 }).eq('id', 5)

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

Ainsert

Bselect

Cdelete

Dupdate

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'insert' to change data instead of 'update'.

Using 'select' when trying to modify data.

The update method modifies existing rows. Here, it updates the 'age' where 'id' equals 5.

4fill in blank

hard

Fill both blanks to delete rows where 'status' is 'inactive' from the 'accounts' table.

Supabase

const { data, error } = await supabase.from('accounts').[1]().[2]('status', 'inactive')

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

Adelete

Bselect

Ceq

Dinsert

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'select' instead of 'delete' to remove data.

Not filtering rows correctly before deleting.

The delete method removes rows. The eq method filters rows where 'status' equals 'inactive'.

5fill in blank

hard

Fill all three blanks to select 'name' and 'email' from 'customers' where 'age' is greater than 25.

Supabase

const { data, error } = await supabase.from('customers').[1](['name', 'email']).[2]('age', [3], 25)

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

Aselect

Bfilter

Cgt

Dinsert

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'insert' instead of 'select' to get data.

Using wrong filter method or operator.

Use select to choose columns, filter to apply conditions, and gt as the operator symbol for greater than.

Practice

1. What does the insert() method do in Supabase?

easy

A. Adds new rows of data to a table

B. Deletes rows from a table

C. Updates existing rows in a table

D. Retrieves data from a table

Solution

1. Step 1: Understand the purpose of insert()

   The insert() method is used to add new data entries (rows) into a database table.

2. Step 2: Differentiate from other methods

   Methods like delete() remove data, update() changes existing data, and select() retrieves data. Only insert() adds new rows.

3. Final Answer:

   Adds new rows of data to a table -> Option A

4. Quick Check:

   insert() = Add rows [OK]

Hint: Insert means add new data rows [OK]

Common Mistakes:

• Confusing insert() with update()
• Thinking insert() deletes data
• Mixing insert() with select()

2. Which of the following is the correct syntax to insert a new user with name 'Alice' into the 'users' table using Supabase client?

easy

A. supabase.insert('users').from({name: 'Alice'})

B. supabase.users.insert('Alice')

C. supabase.table('users').add({name: 'Alice'})

D. supabase.from('users').insert({name: 'Alice'})

Solution

1. Step 1: Recall Supabase insert syntax

   The correct syntax uses supabase.from('table').insert(data) to add data.

2. Step 2: Match syntax with options

   supabase.from('users').insert({name: 'Alice'}) matches the correct pattern: supabase.from('users').insert({name: 'Alice'}). Others misuse method order or names.

3. Final Answer:

   supabase.from('users').insert({name: 'Alice'}) -> Option D

4. Quick Check:

   from('table').insert(data) = correct syntax [OK]

Hint: Use from('table').insert({data}) to add rows [OK]

Common Mistakes:

• Swapping method order like insert().from()
• Using non-existent methods like add()
• Passing data as string instead of object

3. Given this code snippet, what will be the output?

const { data, error } = await supabase
  .from('products')
  .select('*')
  .eq('category', 'books');
console.log(data);

medium

A. An empty array always

B. An error message because of wrong syntax

C. An array of products where category is 'books'

D. All products regardless of category

Solution

1. Step 1: Understand the query filters

   The select('*') fetches all columns, and .eq('category', 'books') filters rows where category equals 'books'.

2. Step 2: Predict the output of console.log(data)

   It will print an array of product objects matching the category 'books'. If no error, data contains matching rows.

3. Final Answer:

   An array of products where category is 'books' -> Option C

4. Quick Check:

   select('*').eq() filters rows = filtered array [OK]

Hint: eq() filters rows by column value [OK]

Common Mistakes:

• Thinking select('*') returns all rows without filter
• Assuming syntax error due to chaining
• Expecting empty array without data

4. What is wrong with this Supabase insert code?

const { data, error } = await supabase
  .from('orders')
  .insert(['item', 'quantity']);

medium

A. insert() expects an array of objects, not an array of strings

B. from() should be called after insert()

C. insert() cannot be awaited

D. Missing .select() after insert()

Solution

1. Step 1: Check insert() argument type

   The insert() method requires an array of objects representing rows, e.g., [{item: 'apple', quantity: 2}]. Passing an array of strings is invalid.

2. Step 2: Verify method order and usage

   Calling from() before insert() is correct. Awaiting insert() is valid. .select() after insert() is optional for returning data.

3. Final Answer:

   insert() expects an array of objects, not an array of strings -> Option A

4. Quick Check:

   insert() needs array of objects [OK]

Hint: Insert data as objects inside array [OK]

Common Mistakes:

• Passing array of strings instead of objects
• Calling from() after insert()
• Thinking insert() can't be awaited

5. You want to insert multiple new users and then immediately fetch all users with age over 20. Which code correctly does this in Supabase?

hard

A. const { data } = await supabase.from('users').select('*').gt('age', 20);
await supabase.from('users').insert([{name: 'Bob', age: 25}, {name: 'Eve', age: 22}]);

B. await supabase.from('users').insert([{name: 'Bob', age: 25}, {name: 'Eve', age: 22}]);
const { data } = await supabase.from('users').select('*').gt('age', 20);

C. await supabase.from('users').insert({name: 'Bob', age: 25, name: 'Eve', age: 22});
const { data } = await supabase.from('users').select('*').gt('age', 20);

D. await supabase.from('users').insert([{name: 'Bob', age: 25}, {name: 'Eve', age: 22}]).select('*').gt('age', 20);

Solution

1. Step 1: Insert multiple users correctly

   Use insert() with an array of objects: [{name: 'Bob', age: 25}, {name: 'Eve', age: 22}]. A single malformed object is invalid.

2. Step 2: Query users with age > 20 after insertion

   Insert first, then use a separate query: supabase.from('users').select('*').gt('age', 20). Querying before insert misses new data; chaining select().gt() after insert() is invalid.

3. Final Answer:

   Insert first, then query with .gt('age', 20) -> Option B

4. Quick Check:

   Insert then query = correct order [OK]

Hint: Insert first, then query filtered data [OK]

Common Mistakes:

• Querying before inserting new data
• Passing single object instead of array for multiple inserts
• Chaining select() after insert() incorrectly