Describe your experience with PostgreSQL database, including functions used and solutions implemented.

In working with PostgreSQL, I used the following capabilities:

• Creating and managing databases and tables using SQL.
• Using indexes to optimize queries.
• Writing complex queries with JOINs, subqueries, and aggregations.
• Using transactions to ensure data integrity.
• Setting up roles and access rights for security.
• Using functions and triggers to automate business logic.
• Backing up and restoring data with pg_dump and pg_restore.

In projects, I implemented:

• Database schema migrations using tools like Flyway or Liquibase.
• Query optimization to improve performance.
• Replication and configuring fault tolerance.

An example of a simple query using a transaction:

BEGIN;
INSERT INTO users (name, email) VALUES ('Ivan', 'ivan@example.com');
UPDATE accounts SET balance = balance - 100 WHERE user_id = 1;
COMMIT;