What are the main advantages and disadvantages of using indexes in a database?

Indexes in a database significantly speed up search and data retrieval operations, as they allow quick access to the required records without scanning the entire table. Main advantages:

• Speeding up SELECT queries — especially when filtering and sorting.
• Improving the performance of JOIN operations.
• Ensuring data uniqueness (e.g., unique indexes).

Disadvantages:

• Additional disk space consumption for storing indexes.
• Slowing down insert, update, and delete operations, as indexes need to be updated.
• Complexity in choosing the right indexes — excessive indexing can degrade performance.

Example: if you have a user table with millions of records, an index on the email field will allow you to quickly find a user by email instead of scanning all records.