Index Creation StQuerygies

-- B-tree index for equality and range queries
CREATE INDEX idx_products_category_price
    ON products (category_id, unit_price);

-- Partial index: only index active products
CREATE INDEX idx_products_active
    ON products (product_name)
    WHERE discontinued_date IS NULL;

-- Expression index for case-insensitive searches
CREATE INDEX idx_customers_email_lower
    ON customers (LOWER(email));

-- Unique index for constraint enforcement
CREATE UNIQUE INDEX idx_orders_customer_date
    ON orders (customer_id, order_date)
    WHERE status != 'cancelled';

-- Covering index (INCLUDE) for index-only scans
CREATE INDEX idx_order_items_covering
    ON order_items (order_id)
    INCLUDE (product_id, quantity, unit_price);

-- Concurrent index creation (no table locks)
CREATE INDEX CONCURRENTLY idx_products_name
    ON products (product_name);