Indexes - Speed Up Queries

An Index helps the database find data faster.

Like a book index - instead of reading every page, jump to the right spot.

Create an index:

CREATE INDEX idx_salary ON employees(salary);

Now queries filtering by salary are much faster!

Types:

• B-tree - default, good for ranges
• Hash - exact matches only
• Composite - multiple columns

Trade-offs:

• Faster reads
• Slower writes (index must update)
• Uses storage space

Index columns you frequently filter or join on.