What Is a View?
A view gives a name to a query so that other queries can use it like a table. An ordinary PostgreSQL view stores the definition, not a separate copy of the result.
Example
Assume orders(id, customer_id, status, total). A view can give several callers the same definition of a paid order.
CREATE VIEW paid_orders AS
SELECT id, customer_id, total
FROM orders
WHERE status = 'PAID';
SELECT customer_id, SUM(total)
FROM paid_orders
GROUP BY customer_id;
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Why Use It?
•
Reuse a query without repeating its filters in every caller.
•
Expose a stable set of columns while keeping callers away from unnecessary implementation details.
•
Make reporting queries easier to read by naming an intermediate result.
Things to Check
A view is not automatically a performance improvement: the database still executes the underlying query. A materialized view stores results, but its refresh policy determines how current those results are.
Some simple views are updatable; complex joins and aggregates may not be. A view is also not a complete security policy by itself. Review privileges, row-level security, and the database’s view security rules before using it to restrict access.
