Database Indexing Strategies

# Database Indexing Strategies Database indexes are crucial for query performance. Understanding when and how to use them can dramatically improve your application's speed. ## What Are Indexes? An index is a data structure that improves the speed of data retrieval operations on a database table. ## Types of Indexes 1. **Primary Index**: Automatically created on primary key 2. **Unique Index**: Ensures column uniqueness 3. **Composite Index**: Index on multiple columns 4. **Full-Text Index**: For text search operations ## Creating Indexes ```sql -- Single column index CREATE INDEX idx_users_email ON users(email); -- Composite index CREATE INDEX idx_users_name ON users(last_name, first_name); -- Unique index CREATE UNIQUE INDEX idx_users_username ON users(username); ``` ## When to Use Indexes - Columns frequently used in WHERE clauses - Columns used in JOIN operations - Columns used in ORDER BY clauses - Foreign key columns ## When NOT to Use Indexes - Small tables - Columns with high write frequency - Columns with low cardinality Remember: indexes speed up reads but slow down writes. Balance is key.