Ensure Unique Email Entries with a Unique Index

Creating a Unique Index in PostgreSQL

Write a PostgreSQL query to create a unique index on a column to enforce uniqueness.

Solution:

-- Specify the action to create a unique index.
CREATE UNIQUE INDEX idx_employees_email 
-- Define the target table and column for the unique index.
ON Employees(email);

Explanation:

• Purpose of the Query:
• To enforce that each email in the Employees table is unique, preventing duplicate entries.
• Key Components:
• CREATE UNIQUE INDEX idx_employees_email : Creates an index that enforces uniqueness.
• ON Employees(email) : Specifies the table and column to index.

Notes:

• Unique indexes combine performance benefits with data integrity checks.
• Use unique indexes when you want to ensure no duplicate values are inserted.

For more Practice: Solve these Related Problems:

• Write a PostgreSQL query to create a unique index on the "username" column in the "Users" table.
• Write a PostgreSQL query to create a unique index on the "serial_number" column in the "Devices" table.
• Write a PostgreSQL query to create a unique index on the "license_plate" column in the "Vehicles" table.
• Write a PostgreSQL query to create a unique index on the "registration_number" column in the "Registrations" table.

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