ms sql server - Beuth Hochschule für Technik Berlin

Typen von Datenbanksystemen
4 Objektorientierte Datenbanksystemene
Beispiele: POET, ObjectStore, Versant
Objektorientierte Datenbanksysteme müssen haben:
Komplex strukturierte Objekte (wie Java und C++)
Objektidentität
Kapselung
Klassen
Spezialisierungshierarchien
Vererbung von Methoden, evtl. Mehrfachvererbung
Statische Typisierung
Datenbankprogrammiersprache (z.Zt. Java und C++)
Erweiterbarkeit
Versionsverwaltung
Persistente Speicherung
Sekundärspeicher
Weitere Eigenschaften
Anfragesprache
Mehrbenutzerbetrieb
Transaktionen
Verteilte Datenhaltung
Lange Transaktionen
Es geht um:
Objektmodell (Javaanpassung, ODL, Präprozessor oder Postprozessor)
Objektspezifikationssprache
Objektanfragesprache
Programmiersprachenanbindungen
Einige Charakteristika:
Java-Klassen sind Datenbankdatentypen.
Mismatch zwischen Programmiersprache und SQL: Navigation und Resultatorientierung
ODL und OQL
TFH Berlin/Steyer
Typen von Datenbanksystemen
Anwendung Bookshop
ER-Modell
Author
Category
Publisher
Book
OrderItem
BookOrder
Customer
Ablauf der Programmentwicklung und -nutzung
1) Compilation des Programms (Java-like)
2) Postprozessor (oder Praeprozessor)
verarbeitet die Java-Datentypdefinitionen.
(In einer Datei stehen Datenbank, persistent gewünschte Klassen, gewünschte Indexe)
3) Ausführung (Java-like)/Programmablauf
öffnen der Datenbank
Beginn einer Transaktion
suchen, wenn gefunden
-> Ausgabe
wenn nicht gefunden -> einfügen
TFH Berlin/Steyer
Typen von Datenbanksystemen
void PopulateObj() throws ODMGException {
Transaction txn = new Transaction ();
txn.begin;
try {
Author a1 = new Author (“Andreas”, “Heuer”);
Author a2 = new Author (“Gunter”,”Saake”);
Book book = new Book (“3-8266-0513-6”);
Book.setTitle (“Datenbabnken”);
Book.setPrice (69.0);
Book.addAuthor (a1);
Book.addAuthor (a2);
a1.addBook (book);
a2.addBook (book);
dbase.bind (book, “Mein Buch”);
} catch (ODMGException exc) {
txn.abort ();
throw exc;
}
txn.commit ();
}
public static void main (String args[]) {
if (args.length != 1) {
System.out.println (‘usage: Populate dbname’);
System.exit(1));
}
try {
Database db = Database.open (args[0];
Database.openReadWrite);
Populate app = new populate (db);
If (! App.lookupObj ();
App.populateObj ();
} catch (ODMGException exc) {
exc.printStackTrace ();
}
}
}
TFH Berlin/Steyer
Typen von Datenbanksystemen
Book.java
package bookshop;
import COM.POET.odmg.collection.*;
import java.util.Enumeration;
/**
*
*/
public class Book {
String isbn, title;
Double price;
Publisher publishedBy;
// invers zu
Category classification;
// invers zu
ListOfObject writtenBy;
// invers zu
int stock;
public Book (String isbn) {
isbn = isbn;
writtenBy = new ListOfObject ();
}
/**
*
*/
public String getISBN () {
return isbn;
}
public void setPrice (double p) {
price = p;
}
public void setTitle (String s) {
title = s;
}
public void setPublisher (Publisher p) {
publishedBy = p;
}
public Publisher getPublisher () {
return publishedBy;
}
public void addAuthor (Author a) {
writtenBy.add (a);
}
Enumeration getAuthors () {
Return writtenBy.elements ();
}
TFH Berlin/Steyer
Typen von Datenbanksystemen
public void setCategory (Category c) {
classifiedIn = c;
}
public void Category getCategory () {
return classifiedIn;
}
public void setStock (int num) {
stock = num;
}
public double getPrice () {
return price;
}
public void getStock () {
return stock;
}
/**
*
*/
public boolean reduceStock (int num) {
if (stock > num) {
stock -= num;
return true;
else
return false;
}
/**
*
*/
public String toString () {
return “Book [“ + isbn + “, “ + title + “ : “ + stock + “]”;
}
}
Author.java
package bookshop;
import COM.POET.odmg.collection.*;
import java.util.Enumeration;
/**
*
*/
TFH Berlin/Steyer
Typen von Datenbanksystemen
public class Author {
String firstname, lastname;
ListOfObject hasWritten;
// invers zu
public Author (String first, String last) {
firstname = first;
lastname = last;
hasWritten = new listOfObject();
}
/**
*
*/
public void addBook (Book b) {
hasWritten.add (b);;
}
public Enumeration getBooks () {
return hasWritten.elements ();
}
}
Customer.java
package bookshop;
/**
*
*/
public class Customer {
int id;
String name, city;
Int zipcode;
public Customer (int id, String s) {
id = id;
name = s;
}
/**
*
*/
public void setAddress (int zip, String s) {
zipcode = zip;
city = s;
}
public String getName () {
return lastname;
}
TFH Berlin/Steyer
Typen von Datenbanksystemen
public long getCustId () {
return id;
}
}
BookOrder.java
package bookshop;
import java.util.Date;
import java.util.Enumeration;
import COM.POET.odmg.collection.*;
/**
*
*/
public class BookOrder {
public final static int OPEN = 1;
public final static int DELIVERED = 2;
double price;
Date date;
ListOfObject contains;
int status;
Customer orderedBy;
public BookOrder () {
price = 0.0;
date = new Date ();
contains = new ListOfObject ();
status = OPEN;
}
/**
*
*/
public void addItem (Book b, int n) {
contains.add (new OrderItem (b, n));
}
/**
*
*/
public void setCustomer (Customer cust) {
orderedBy = cust;
}
public Date getDate () {
return date;
}
TFH Berlin/Steyer
Typen von Datenbanksystemen
public Enumeration getItems () {
return contains.elements ();
}
/**
*
*/
public boolean deliver () {
Enumeration e;
}
//
e = getItems ();
while (e.hasMoreElements ()) {
OrderItem item = (OrderItem) e.nextElement ();
If (! Item.isAvailable ())
Return false;
}
//
calculatePrice ();
//
e = getItems ();
while (e.hasMoreElements ()) {
OrderItem item = (OrderItem) e.nextElement ();
Item.book.reduceStock (item.num);
}
//
status = DELIVERED;
return true;
}
/**
*
*/
private void calculatePrice () {
price = 0.0;
Enumeration e = getItems ();
while (e.hasMoreElements ()) {
OrderItem item = (OrderItem) e.nextElement ();
Price += item.getPrice ();
}
}
}
TFH Berlin/Steyer
Typen von Datenbanksystemen
OrderItem.java
package bookshop;
/**
*
*/
class OrderItem {
Book book;
int num;
public OrderItem (Book b, int n) {
book = b;
num = n;
}
/**
*
*/
public boolean isAvailable () {
return book.getStock () >= num;
}
/**
*
*/
public double getPrice () {
return book.getPrice () = num;
}
}
Publisher.java
package bookshop;
import COM.POET.odmg.collection.*;
import java.util.Enumeration;
/**
*
*/
public class Publisher {
String name;
String address;
ListOfObject hasPublished;
//
public Publisher (String name, String addr){
name = name;
address = addr;
hasPublished = new ListOfObject ();
}
TFH Berlin/Steyer
Typen von Datenbanksystemen
/**
*
*/
public String getName () {
return name;
}
public String getAddress () {
return address;
}
public String addBook (Book b) {
hasPublished.add (b);
}
void Enumeration getBooks () {
return hasPublished.elements ();
}
}
Category.java
package bookshop;
import COM.POET.odmg.collection.*;
import java.util.Enumeration;
/**
*
*/
public class Category {
String name;
ListOfObject contains;
//
public Category (String s) {
name = s;
contains = new ListOfObject ();
}
/**
*
*/
public String getName () {
return name;
}
public String addBook (Book b) {
contains.add (b);
}
public Enumeration getBooks () {
return contains.elements ();
}
}
TFH Berlin/Steyer
Typen von Datenbanksystemen
Objekt-Browser
Zeigt an:
Klassen, roots, views
TFH Berlin/Steyer