Constraint naming conventions in SQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to name a primary key constraint following the convention.

SQL

ALTER TABLE employees ADD CONSTRAINT [1] PRIMARY KEY (employee_id);

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

Aprimary_key

Bpk_employees

Ckey_employee

Demp_pk

Attempts:

3 left

💡 Hint

Common Mistakes

Using generic names like 'primary_key' without table reference.

Not using the 'pk_' prefix.

The convention is to prefix primary key constraints with pk_ followed by the table name.

2fill in blank

medium

Complete the code to name a foreign key constraint following the convention.

SQL

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

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Afk_customer

Bforeign_key

Corders_fk

Dfk_orders_customers

Attempts:

3 left

💡 Hint

Common Mistakes

Using vague names like 'foreign_key' without table names.

Omitting the referenced table name.

Foreign key constraints are named with the prefix fk_ followed by the referencing and referenced table names.

3fill in blank

hard

Fix the error in naming a unique constraint following the convention.

SQL

ALTER TABLE products ADD CONSTRAINT [1] UNIQUE (product_code);

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Auq_products_product_code

Bunique_products_code

Cunique_code

Dproducts_uniq

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'unique_' prefix instead of 'uq_'.

Not including column name in the constraint name.

Unique constraints use the prefix uq_ followed by the table and column names for clarity.

4fill in blank

hard

Fill both blanks to name a check constraint following the convention.

SQL

ALTER TABLE employees ADD CONSTRAINT [1] CHECK (salary [2] 0);

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Achk_employees_salary

B>

C<

Dsalary_positive

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong prefix like 'check_' instead of 'chk_'.

Using '<' instead of '>' for salary check.

Check constraints use the prefix chk_ followed by table and column names. The condition should ensure salary is greater than zero.

5fill in blank

hard

Fill both blanks to name a default constraint following the convention.

SQL

ALTER TABLE orders ADD CONSTRAINT [1] DEFAULT [2] FOR order_status;

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Adf_orders_order_status

B'pending'

Ddefault_status

Attempts:

3 left

💡 Hint

Common Mistakes

Using extra syntax after the column name.

Not quoting string default values.

Default constraints use the prefix df_ followed by table and column names. The default value is set without extra syntax after the column name.