One-to-many relationship design in SQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a table named 'orders' with a primary key column 'order_id'.

SQL

CREATE TABLE orders (order_id [1]);

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AINT PRIMARY KEY

BVARCHAR(255)

CFLOAT

DDATE

Attempts:

3 left

💡 Hint

Common Mistakes

Using VARCHAR instead of INT for the primary key.

Not specifying PRIMARY KEY.

The 'order_id' column should be an integer and set as the primary key to uniquely identify each order.

2fill in blank

medium

Complete the code to add a foreign key column 'customer_id' to the 'orders' table.

SQL

ALTER TABLE orders ADD COLUMN customer_id [1];

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AINT

BDATE

CTEXT

DBOOLEAN

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different data type than the referenced primary key.

Using a non-numeric type for IDs.

The 'customer_id' should be an integer to match the primary key type of the 'customers' table.

3fill in blank

hard

Fix the error in the foreign key constraint syntax to link 'customer_id' in 'orders' to 'id' in 'customers'.

SQL

ALTER TABLE orders ADD CONSTRAINT fk_customer FOREIGN KEY (customer_id) REFERENCES customers([1]);

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Acustomer_id

Border_id

Cid

Dorder_date

Attempts:

3 left

💡 Hint

Common Mistakes

Referencing a non-primary key column.

Using the foreign key column name instead of the referenced column.

The foreign key must reference the primary key column 'id' in the 'customers' table.

4fill in blank

hard

Fill both blanks to create a 'customers' table with a primary key 'id' and a 'name' column.

SQL

CREATE TABLE customers (id [1], name [2]);

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AINT PRIMARY KEY

BVARCHAR(100)

CTEXT

DDATE

Attempts:

3 left

💡 Hint

Common Mistakes

Using DATE for the name column.

Not setting the primary key on 'id'.

The 'id' column is an integer primary key, and 'name' is a variable character string with max length 100.

5fill in blank

hard

Fill all three blanks to insert a new order with order_id 101, customer_id 5, and order_date '2024-06-01'.

SQL

INSERT INTO orders (order_id, customer_id, order_date) VALUES ([1], [2], '[3]');

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A100

B5

C2024-06-01

D101

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping order_id and customer_id values.

Not quoting the date string.

The order_id is 101, customer_id is 5, and the order_date is '2024-06-01'.