Table relationships in Supabase - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a foreign key relationship in Supabase SQL.

Supabase

CREATE TABLE orders (id SERIAL PRIMARY KEY, user_id INTEGER [1] REFERENCES users(id));

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AFOREIGN KEY

BUNIQUE

CINDEX

DCONSTRAINT

Attempts:

3 left

💡 Hint

Common Mistakes

Using CONSTRAINT without FOREIGN KEY keyword.

Using INDEX or UNIQUE which do not define relationships.

The FOREIGN KEY keyword defines a foreign key relationship linking user_id in orders to id in users.

2fill in blank

medium

Complete the code to create a one-to-many relationship between users and posts.

Supabase

CREATE TABLE posts (id SERIAL PRIMARY KEY, author_id INTEGER [1] users(id));

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AREFERENCES

BJOIN

CCONNECTS

DLINKS

Attempts:

3 left

💡 Hint

Common Mistakes

Using JOIN which is for queries, not table definitions.

Using LINKS or CONNECTS which are not SQL keywords.

The REFERENCES keyword creates a foreign key pointing author_id in posts to id in users, establishing a one-to-many relationship.

3fill in blank

hard

Fix the error in the foreign key constraint syntax.

Supabase

ALTER TABLE comments ADD CONSTRAINT fk_post_id FOREIGN KEY (post_id) [1] posts(id);

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ALINKS

BCONNECTS

CREFERENCES

DJOINS

Attempts:

3 left

💡 Hint

Common Mistakes

Using LINKS, CONNECTS, or JOINS which are invalid in this context.

The correct syntax uses REFERENCES to specify the referenced table and column in a foreign key constraint.

4fill in blank

hard

Fill both blanks to create a many-to-many relationship using a join table.

Supabase

CREATE TABLE [1] (user_id INTEGER [2] users(id), role_id INTEGER REFERENCES roles(id));

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Auser_roles

BREFERENCES

CFOREIGN KEY

Droles_users

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect table names that don't reflect the relationship.

Using FOREIGN KEY keyword alone without REFERENCES.

The join table is commonly named user_roles and the foreign key uses REFERENCES to link user_id to users(id).

5fill in blank

hard

Fill all three blanks to define a composite primary key and foreign keys in a join table.

Supabase

CREATE TABLE [1] (user_id INTEGER [2] users(id), role_id INTEGER REFERENCES roles(id), PRIMARY KEY ([3]));

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Auser_roles

BREFERENCES

Cuser_id, role_id

DFOREIGN KEY

Attempts:

3 left

💡 Hint

Common Mistakes

Using FOREIGN KEY keyword without REFERENCES.

Not defining a composite primary key for the join table.

The join table user_roles uses REFERENCES to link foreign keys and defines a composite primary key on user_id, role_id to ensure uniqueness.