Postgres Jdbc Driver Guide

// PreparedStatement (preferred) String sql = "SELECT * FROM users WHERE age > ? AND city = ?"; try (PreparedStatement pstmt = conn.prepareStatement(sql)) pstmt.setInt(1, 18); pstmt.setString(2, "Paris"); ResultSet rs = pstmt.executeQuery();

8.1 Common Errors | Error | Solution | |-------|----------| | The connection attempt failed | Check PostgreSQL running, firewall, pg_hba.conf | | No suitable driver found | Add JDBC jar to classpath | | FATAL: no pg_hba.conf entry | Add client IP/method to pg_hba.conf | | PSQLException: This connection has been closed | Reconnect or use connection pool | | PSQLException: Out of memory | Increase JVM heap or reduce result set size | 8.2 Best Practices Checklist ✅ Always use PreparedStatement (prevents SQL injection) ✅ Use try-with-resources for automatic closing ✅ Implement connection pooling (HikariCP) ✅ Set reasonable timeouts (connect, socket, login) ✅ Use fetchSize for large result sets postgres jdbc driver

// Store array Integer[] intArray = 1, 2, 3; Array array = conn.createArrayOf("integer", intArray); pstmt.setArray(1, array); // Read array Array resultArray = rs.getArray("int_array"); Integer[] values = (Integer[]) resultArray.getArray(); // PreparedStatement (preferred) String sql = "SELECT *