Object-relational mapping (JPA, Hibernate)

Transkript

1 Vysoká škola báňská - technická univerzita Ostrava 17. března 2010

2 Obsah

3 namapovat chování objektového světa do relačních struktur a naopak, tak aby spolu mohli jednoduše komunikovat většina moderních aplikací již s databázemi pracuje rozdílná rozhraní databází vedla k vytvoření JDBC JDBC je však stále relační jazyk oproti tomu, Java je objektově orientovaná ORM se snaží vyřešit neshody mezi těmito přístupy

4 dědičnost public class User{ private String Name; public class Student extends User{ private double credits; public class Teacher extends User{ private int salary;

5 nespojitost public class User{ private String Name; private Address address; public class Address{ private String city; private String country; Table USER: NAME CITY COUNTRY

6 asociace public class User{ private Address address; public class Address{ private string city; private string country; Table ADDRESS ADDRESS_ID CITY COUNTRY Table USER USER_ID NAME ADDRESS_ID (Fk)

7 ostatní identita a rovnost (identity and equality) datové typy

8 Java Persistence API (JPA)

9 mapování public class Student public class public class Student {

10 mapování identit private = public Long getid() { return id; student = new Student(); Long studentid = (Long)session.save(student);

11 = "t_student") public class = GenerationType.AUTO) private Long = false) private String = false, length = 30) private String = 15) private String = "e_mail") private String ; private Integer age;

12 private void validatephonenumber(){ if (telephone.charat(0)!= + ) throw new IllegalArgumentException("Invalid phone number");

13 mapování //nezapise do databaze public int getactive() { return //format casu public Date getbirthdate() { return birthdate;

14 @Table(name="BASIC_USER") public class User{ protected long id; protected String name;

15 dědičnost public class Customer extends User{ protected public class Employee extends User{ protected String rank; BASIC_USER Table ID NAME CREDIT_LIMIT RANK DISCRIMINATOR

16 dědičnost public abstract class User{ protected long id; protected = GenerationType.AUTO) public long getid() public class Customer extends User{ protected double creditlimit;

17 public class User implements Serializable{ protected long id; protected public class Employee extends User{ protected String rank;

18 dědičnost BASIC_USER Table ID NAME Employee table EMPLOYEE_ID RANK //i primarni i cizi klic

19 kolekce Table STUDENT STUDENT_ID Table PHONE STUDENT_ID NUMBER

20 (targetelement = name="phone"; @org.hibernate.annotations.sort (type=org.hibernate.annotations.sorttype.natural) public Set<String> getphones() {

21 vazby = "t_customer") public class = "t_address") public class private Long id; private String firstname; private String lastname; private String telephone; private String ; private private Long id; private String street; private String city; private String zipcode; private String country; private Address homeaddress;

22 = "t_customer") public class private Long id; = = "address_fk", nullable = false) private Address homeaddress;

23 vazby public abstract class private Long id; = FetchType.LAZY, cascade = = "t_delivery_addresses", joincolumns = {@JoinColumn(name = "customer_fk"), inversejoincolumns = {@JoinColumn(name = "address_fk")) private List<Address> deliveryaddresses = new ArrayList<Address>(); public void adddeliveryaddress(address deliveryaddress) { deliveryaddresses.add(deliveryaddress);

24 = "t_address") public class Address private Long (cascade = = "t_address_tag", joincolumns = = "address_fk"), inversejoincolumns = = "tag_fk")) private List<Tag> tags = = "t_tag") public class Tag private String private List<Address> addresses

25 dotazy // zakazniky se jmenem john Query query = em.createquery ("SELECT c FROM Customer c WHERE c.firstname= John "); List<Customer> customers = query.getresultlist(); // to same s pouzitim parametru Query query = em.createquery ("SELECT c FROM Customer c WHERE c.firstname=:param"); query.setparameter(":param", "John"); List<Customer> customers = query.getresultlist();

26 dotazy // Vsechny adresy z London nebo New York query = em.createquery ("SELECT a FROM Address a WHERE a.city IN ( London, New York )" addresses = query.getresultlist(); // Vsechny adresy s alespon jednim tagem query = em.createquery ("SELECT a FROM Address a WHERE a.tags IS NOT EMPTY"); addresses = query.getresultlist(); // Vsechny adresy s week-end tagem. query = em.createquery ("SELECT a FROM Address a WHERE :param MEMBER OF a.tags"); query.setparameter("param", new Tag("week-ends")); addresses = query.getresultlist();

27 struktura tabulky popisující atributy třídy prvků zahrnující body, linie, plochy apod. soubory rastů a rastrové katalogy

28 typy prvků

29 typy prvků fromát geodat formát WKT nebo WKB (well-known text/binary) WKT - POINT(10 10), LINESTRING(10 10, 20 20, 30 40), POLYGON((10 10, 10 20, 20 20, 20 15, 10 10)) apod. WKB F03F F03F (POINT (1,1)) metody - GeomFromText(wkt,srid), LineFromText(wkt,srid), MPointFromText(wkt,srid) apod.

30 dotazy CREATE TABLE address ( address CHAR(80) NOT NULL, address_loc POINT NOT NULL, PRIMARY KEY(address), SPATIAL KEY(address_loc) ); CREATE TABLE cab ( cab_id INT AUTO_INCREMENT NOT NULL, cab_driver CHAR(80) NOT NULL, cab_loc POINT NOT NULL, PRIMARY KEY(cab_id), SPATIAL KEY(cab_loc) );

31 dotazy INSERT INTO address VALUES( w 12,GeomFromText( POINT( ) )); INSERT INTO address VALUES( w 56,GeomFromText( POINT( ) )); INSERT INTO address VALUES( w 78,GeomFromText( POINT( ) )); INSERT INTO address VALUES( w 97,GeomFromText( POINT( ) )); INSERT INTO address VALUES( w 99,GeomFromText( POINT( ) )); INSERT INTO address VALUES( n 10,GeomFromText( POINT( ) )); INSERT INTO address VALUES( n 20,GeomFromText( POINT( ) )); INSERT INTO address VALUES( n 45,GeomFromText( POINT( ) )); INSERT INTO cab VALUES(0, Joe,GeomFromText( POINT( ) )); INSERT INTO cab VALUES(0, Bill,GeomFromText( POINT( ) )); INSERT INTO cab VALUES(0, Sam,GeomFromText( POINT( ) ));

32 dotazy SELECT c.cab_driver, ROUND(GLength(LineStringFromWKB(LineString(AsBinary(c.cab_loc), AsBinary(a.address_loc))))) AS distance FROM cab c, address a WHERE a.address = Foobar street 99 ORDER BY distance ASC LIMIT 1; cab_driver distance Sam row in set (0.00 sec)

33 Děkuji za pozornost