confusion over using values in Java within SQL statements -

confusion over using values in Java within SQL statements -

i need retrieve list of vehicle registrations sql database , set them dropdown list in java gui. 1 time vehicle registration selected (as part of login sequence) list want utilize in "where" statement of subsequent sql queries made database things inventory statuses etc vehicle.

i have done first part i.e. retrieved list database , displayed veh regs in dropdown user select, have managed display in optional panel display in class in jlabel box cannot seem figure out how utilize selected veh reg in seperate query class i.e part of select/where statement?

i have been trying find solution getting confused on whether utilize array list , set registration number , how create available other classes can retrieve value utilize in sql statement. quite lost advice in right direction helpful.

i new java , programming altogether if sense need create sarcastic (you such noob) type comments don't bother posting!

this code grabs registrations database , adds them combo box in 1 gui:

private void populateregistration() { seek { // create connection database pst = conn.preparestatement("select vehicleregistrationnumber vehicle;"); // create query vehicle regs rs = pst.executequery(); // add together vehicle regs combobox while (rs.next()) { jcombobox1.additem(rs.getstring("vehicleregistrationnumber")); } } grab (sqlexception ex) { logger.getlogger(login_gui.class.getname()).log(level.severe, null, ex); }

this code in gui class shows vehicle registration in dialogue box , shows in text field in gui:

public arraylist<string> gettablecontent() { databaseconnection db = new databaseconnection(); seek { //sql homecoming statement string newquery= "select p.patientfirstname, p.patientlastname, p.patienthousenumber, p.patientstreetname, p.patientpostcode, p.patientbreathing, p.probleminformation, c.ampdscategory, \n" + "i.numberhurt,t.taskclosed, h.hospitalspaceavailable, h.hospitalname, h.hospitalpostcode, v.vehicleregistrationnumber, em.datetimereported\n" + "from patient p\n" + "join category c\n" + "on c.category_id = p.categoryid\n" + "--and p.patient_id = 2\n" + "join incident i\n" + "on i.incident_id = p.incidentid\n" + "join task t\n" + "on t.incidentid = i.incident_id\n" + "join hospital h\n" + "on h.hospital_id = t.hospitalid\n" + "join vehicle v\n" + "on t.task_id = v.taskid\n" + "join eccpersonnel ec\n" + "on i.eccpersonnelid = ec.eccpersonnel_id\n" + "join emergencycall em\n" + "on ec.callid = em.call_id\n" + "where t.task_id=1" + "--where v.vehicleregistrationnumber = '?'";

i know sql ugly works refine later if time. believe need define ? have no thought how reference ? vehreg value!!

first should allways close have opened. in populateregistration() not forget rs.close() , pst.close().

next reference ? vehreg, create preparedstatement , phone call setstring method (supposing vehreg string).

pst = conn.preparestatement(newquery); pst.setstring(1, vehreg); rs = pst.executequery();

(try, catch, declarations, , actual read ommitted brevity)

remember columns numbered starting 1.

java sql