Insert Date Into Database Postgres JDBC

Question

I'm new to Java and also to Postgres.

I have a little project about restaurant and i have a struk(eng: bill) table like this:

and I have a method to inserting information into that table like this:

public int insertBill(int id_karyawan, String tanggal, String waktu, int total) {
    String SQL = "INSERT INTO struk(kode, id_karyawan, tanggal, waktu, total) VALUES (?,?,?,?,?)";
    int id = 0;

    try(Connection conn = connect(); PreparedStatement pstmt = conn.prepareStatement(SQL, Statement.RETURN_GENERATED_KEYS)) {
        pstmt.setInt(1, 1);
        pstmt.setInt(2, id_karyawan);
        pstmt.setString(3, tanggal);
        pstmt.setString(4, waktu);
        pstmt.setInt(5, total);

        int affectedRows = pstmt.executeUpdate();
        if(affectedRows > 0) {
            try(ResultSet rs = pstmt.getGeneratedKeys()) {
                if(rs.next()) {
                    id = rs.getInt(1);
                }
            } catch (SQLException ex) {
                System.out.println(ex.getMessage());
            }
        }
    } catch (SQLException ex) {
        System.out.println(ex.getMessage());
    }
    return id;
}

later, that method will called with this:

int billID = app.insertBill(1, "2017-09-24", "08:00:00", 150000);

The problem is, i dont have any idea about the Date and the time, what should i pass as a parameter? what kind of variable so that the query work well? I've searched about it got some clue to use string. I use string on a query method for now. Any advice?

Answer 1

Since you have said you are new to java, I assume that you would be using Java 8 and The PostgreSQL JDBC driver provides native support for the Java 8 Date and Time API using JDBC 4.2.

Following datatypes for Date/Time are supported by PostgreSQL :

DATE
TIME [ WITHOUT TIMEZONE ]
TIMESTAMP [ WITHOUT TIMEZONE ]
TIMESTAMP WITH TIMEZONE

You can use the LocalDate, LocalTime, LocalDateTime or OffsetDateTime (OffsetDateTime is an immutable representation of a date-time with an offset eg:the value "20th July 2017 at 10:45.24.123456789 +04:00" can be stored in an OffsetDateTime). These classes comes in the java.time package, which was introduced in Java 8, as a new Date-Time API.(It covers several cons of old date-time API like design issues, thread safety, time zone handling issues etc.) However, ZonedDateTime, Instant and OffsetTime / TIME [ WITHOUT TIMEZONE ] are currently not supported in PostgreSQl (as in JDBC 4.2). Now comming to programming part based on you code, you can do it like this.

public int insertBill(int id_karyawan, String tanggal, String waktu, int total) {

LocalDate localDate = LocalDate.now(); //or whatever date you want to use, for passing parameter as string you could use 

                        /*public static LocalDate parse(CharSequence text,
                          DateTimeFormatter formatter)*/

 //   LocalDate ld = LocalDate.of(2017, Month.JULY, 20);
 LocalTime lt = LocalTime.of(8, 0, 0); 

String SQL = "INSERT INTO struk(kode, id_karyawan, tanggal, waktu, total) VALUES (?,?,?,?,?)";
int id = 0;

try(Connection conn = connect(); PreparedStatement pstmt = conn.prepareStatement(SQL, Statement.RETURN_GENERATED_KEYS)) {
pstmt.setInt(1, 1);
pstmt.setInt(2, id_karyawan);
pstmt.setObject(3, localDate);
pstmt.setObject(4, lt);
pstmt.setInt(5, total);

pstmt.executeUpdate(); 
pstmt.close();

---

Hope this helped you. In case you are using Java versions below 8, you could use joda time.