java -postgresql last inserted id on insertion not getting

Question

I have a function for insertion in postgresql as follows:

CREATE OR REPLACE FUNCTION insert_orderhead(order_id integer, order_dt text, customer_id integer, route_id integer, routenum integer, ordertype text, create_station_id integer, create_stationtype text, create_time text, create_user_id integer, tran_time text, tran_user_id integer) RETURNS integer AS $BODY$
INSERT INTO ordermaster
VALUES(DEFAULT,
       order_dt,
       customer_id,
       route_id,
       routenum,
       ordertype,
       create_station_id,
       create_stationtype,
       create_time,
       create_user_id,
       tran_time,
       tran_user_id) returning order_id $BODY$ LANGUAGE SQL VOLATILE COST 100;


ALTER FUNCTION insert_orderhead(integer, text, integer, integer, integer, text, integer, text, text, integer, text, integer) OWNER TO postgres;

And I am using java to insert and I am calling as follows:

cstorderhead = conn.prepareCall("{call insert_orderhead(?,?)}");
                    cstorderhead.setString(1, order_date);
                    cstorderhead.setInt(2, custidup);
                       .........
                    cstorderhead.executeUpdate();

The value is getting inserted correctly.

I need to return the last inserted id here it is the serial auto increment.

I tried as follows:

ResultSet rstd = cstorderhead.getGeneratedKeys();
                    if (rstd.next()) {
                        int newId = rstd.getInt(1);
                            out.print("Value returned=="+newId);
                    }

But it is not returning the last inserted id. What change I need to make my code to get it?

This is the table definition:

create table ordermaster 
(
  order_id serial NOT NULL, order_dt text, customer_id integer, route_id integer, routenum integer, ordertype text, create_station_id integer, create_stationtype text, create_time text, create_user_id integer, tran_time text, tran_user_id integer, CONSTRAINT order_id PRIMARY KEY (order_id)
);

Answer 1

You can't use getGeneratedKeys() with a CallableStatement. However as your insert is "hidden" in the function, you also can't use a regular PreparedStatement with getGeneratedKeys() because the driver will append a RETURNING clause to the SQL statement - which doesn't work with a function call.

I see two solutions to your problem:

1. Change the function to return the value:

CREATE OR REPLACE FUNCTION insert_orderhead(
    p_order_id integer, 
    p_order_dt text, 
    p_customer_id integer, 
    p_route_id integer, 
    p_routenum integer, 
    p_ordertype text, 
    p_create_station_id integer, 
    p_create_stationtype text, 
    p_create_time text, 
    p_create_user_id integer, 
    p_tran_time text, 
    p_tran_user_id integer)
  RETURNS integer AS
$BODY$
   INSERT INTO ordermaster 
     (order_dt, customer_id, route_id, routenum, ordertype, create_station_id, create_stationtype, create_time,create_user_id,tran_time, tran_user_id)
   values 
     (p_order_dt, p_customer_id, p_route_id, p_routenum, p_ordertype, p_create_station_id, p_create_stationtype, p_create_time, p_create_user_id, p_tran_time, p_tran_user_id) 
   returning  orderline_id;
$BODY$
  LANGUAGE sql VOLATILE
  COST 100;

Note that I removed the unused order_id parameter and renamed the other two parameters - because it is usually not a good idea to have parameters with the same name as columns.

Then in your code you can use the function like this:

PreparedStatement pstmt = con.prepareStatement("select insert_order(?,?)");
pstmt.setString(1, "foo");
pstmt.setInt(2, 42);

rs = pstmt.executeQuery();

if (rs.next()) {
  System.out.println("Generated ID is: " + rs.getInt(1));
}

2. Query the sequence manually:

After calling your function, you can run another statement to obtain the last generated sequence value:

ResultSet rs = stmt.executeQuery("select lastval()");
if (rs.next()) {
  System.out.println("Generated ID is: " + rs.getInt(1));
}

The above will only work if the function doesn't insert into multiple tables. If it does, you need to use currval() with the sequence name:

ResultSet rs = stmt.executeQuery("select currval('ordermaster.order_id_seq')");
if (rs.next()) {
  System.out.println("Generated ID is: " + rs.getInt(1));
}