Lesson: JDBC

1. Add dependency:

implementation group: 'org.postgresql', name: 'postgresql', version: '42.6.0' 

2. Load Postgres driver:

Class.forName("org.postgresql.Driver");

3. Create Connection: 

Connection con = DriverManager.getConnection("jdbc:postgresql://localhost:5432/se_21",
        "postgres", "112358");

4. Create Statement:

Statement stmt = con.createStatement();

5. Create ResultSet:

ResultSet rs = stmt.executeQuery("select * from student");

6. Iterate ResultSet:

while (rs.next()) {
    System.out.println(rs.getString("name"));
}

7. Insert into DB with JDBC

String query = "insert into person(name, surname, age, pin, password) values (?, ?, ?, ?, ?)";

PreparedStatement stmt = con.prepareStatement(query);
stmt.setString(1, person.getName());
stmt.setString(2, person.getSurname());
stmt.setInt(3, person.getAge());
stmt.setString(4, person.getPin());
stmt.setString(5, person.getPassword());
int i = stmt.executeUpdate();

8. Select from DB with JDBC

tring query = "select * from person where id = ?";
PreparedStatement stmt = con.prepareStatement(query);
stmt.setInt(1, id);
ResultSet rs = stmt.executeQuery();

9. Update with JDBC

String query = "update person set name = ?, surname = ?, age = ?, pin = ?, password = ? where id = ?";
PreparedStatement stmt = con.prepareStatement(query);
stmt.setString(1, person.getName());
stmt.setString(2, person.getSurname());
stmt.setInt(3, person.getAge());
stmt.setString(4, person.getPin());
stmt.setString(5, person.getPassword());
stmt.setInt(6, id);
int i = stmt.executeUpdate();