java applet qr code reader Ignore the line of code that calls HibernateUtil.getSessionFactory() we ll get to it soon. in Java

Creator QR Code ISO/IEC18004 in Java Ignore the line of code that calls HibernateUtil.getSessionFactory() we ll get to it soon.

Ignore the line of code that calls HibernateUtil.getSessionFactory() we ll get to it soon.
Create QR Code JIS X 0510 In Java
Using Barcode maker for Java Control to generate, create QR Code JIS X 0510 image in Java applications.
www.OnBarcode.com
QR Code ISO/IEC18004 Decoder In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Starting a project
EAN13 Maker In Java
Using Barcode printer for Java Control to generate, create EAN / UCC - 13 image in Java applications.
www.OnBarcode.com
Code 39 Drawer In Java
Using Barcode drawer for Java Control to generate, create ANSI/AIM Code 39 image in Java applications.
www.OnBarcode.com
The first unit of work, if run, results in the execution of something similar to the following SQL:
Create QR Code In Java
Using Barcode creation for Java Control to generate, create QR Code image in Java applications.
www.OnBarcode.com
Drawing Matrix 2D Barcode In Java
Using Barcode creator for Java Control to generate, create Matrix image in Java applications.
www.OnBarcode.com
insert into MESSAGES (MESSAGE_ID, MESSAGE_TEXT, NEXT_MESSAGE_ID) values (1, 'Hello World', null)
Data Matrix 2d Barcode Drawer In Java
Using Barcode drawer for Java Control to generate, create DataMatrix image in Java applications.
www.OnBarcode.com
2/5 Interleaved Drawer In Java
Using Barcode drawer for Java Control to generate, create 2/5 Interleaved image in Java applications.
www.OnBarcode.com
Hold on the MESSAGE_ID column is being initialized to a strange value. You didn t set the id property of message anywhere, so you expect it to be NULL, right Actually, the id property is special. It s an identifier property: It holds a generated unique value. The value is assigned to the Message instance by Hibernate when save() is called. (We ll discuss how the value is generated later.) Look at the second unit of work. The literal string "from Message m order by m.text asc" is a Hibernate query, expressed in HQL. This query is internally translated into the following SQL when list() is called:
QR Code Encoder In Objective-C
Using Barcode creator for iPhone Control to generate, create QR Code JIS X 0510 image in iPhone applications.
www.OnBarcode.com
QR Code JIS X 0510 Recognizer In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
select m.MESSAGE_ID, m.MESSAGE_TEXT, m.NEXT_MESSAGE_ID from MESSAGES m order by m.MESSAGE_TEXT asc
Drawing 1D Barcode In Visual Studio .NET
Using Barcode creation for VS .NET Control to generate, create Linear 1D Barcode image in .NET applications.
www.OnBarcode.com
Painting PDF-417 2d Barcode In None
Using Barcode creation for Online Control to generate, create PDF-417 2d barcode image in Online applications.
www.OnBarcode.com
If you run this main() method (don t try this now you still need to configure Hibernate), the output on your console is as follows:
Scan QR-Code In Visual Basic .NET
Using Barcode reader for Visual Studio .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Print Linear In VS .NET
Using Barcode printer for ASP.NET Control to generate, create Linear Barcode image in ASP.NET applications.
www.OnBarcode.com
1 message(s) found: Hello World
PDF-417 2d Barcode Recognizer In Java
Using Barcode scanner for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Making Code 3/9 In None
Using Barcode generation for Font Control to generate, create ANSI/AIM Code 39 image in Font applications.
www.OnBarcode.com
If you ve never used an ORM tool like Hibernate before, you probably expected to see the SQL statements somewhere in the code or mapping metadata, but they aren t there. All SQL is generated at runtime (actually, at startup for all reusable SQL statements). Your next step would normally be configuring Hibernate. However, if you feel confident, you can add two other Hibernate features automatic dirty checking and cascading in a third unit of work by adding the following code to your main application:
Data Matrix ECC200 Encoder In Objective-C
Using Barcode drawer for iPad Control to generate, create Data Matrix 2d barcode image in iPad applications.
www.OnBarcode.com
QR Code ISO/IEC18004 Printer In Objective-C
Using Barcode creator for iPhone Control to generate, create QR Code image in iPhone applications.
www.OnBarcode.com
// Third unit of work Session thirdSession = HibernateUtil.getSessionFactory().openSession(); Transaction thirdTransaction = thirdSession.beginTransaction(); // msgId holds the identifier value of the first message message = (Message) thirdSession.get( Message.class, msgId ); message.setText( "Greetings Earthling" ); message.setNextMessage( new Message( "Take me to your leader (please)" ) ); thirdTransaction.commit(); thirdSession.close();
Creating UPCA In Java
Using Barcode creation for Android Control to generate, create GS1 - 12 image in Android applications.
www.OnBarcode.com
UPC-A Supplement 2 Recognizer In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Starting a Hibernate project
This code calls three SQL statements inside the same database transaction:
select m.MESSAGE_ID, m.MESSAGE_TEXT, m.NEXT_MESSAGE_ID from MESSAGES m where m.MESSAGE_ID = 1 insert into MESSAGES (MESSAGE_ID, MESSAGE_TEXT, NEXT_MESSAGE_ID) values (2, 'Take me to your leader (please)', null) update MESSAGES set MESSAGE_TEXT = 'Greetings Earthling', NEXT_MESSAGE_ID = 2 where MESSAGE_ID = 1
Notice how Hibernate detected the modification to the text and nextMessage properties of the first message and automatically updated the database Hibernate did automatic dirty checking. This feature saves you the effort of explicitly asking Hibernate to update the database when you modify the state of an object inside a unit of work. Similarly, the new message was made persistent when a reference was created from the first message. This feature is called cascading save. It saves you the effort of explicitly making the new object persistent by calling save(), as long as it s reachable by an already persistent instance. Also notice that the ordering of the SQL statements isn t the same as the order in which you set property values. Hibernate uses a sophisticated algorithm to determine an efficient ordering that avoids database foreign key constraint violations but is still sufficiently predictable to the user. This feature is called transactional write-behind. If you ran the application now, you d get the following output (you d have to copy the second unit of work after the third to execute the query-display step again):
2 message(s) found: Greetings Earthling Take me to your leader (please)
You now have domain classes, an XML mapping file, and the Hello World application code that loads and stores objects. Before you can compile and run this code, you need to create Hibernate s configuration (and resolve the mystery of the HibernateUtil class).
Hibernate configuration and startup
The regular way of initializing Hibernate is to build a SessionFactory object from a Configuration object. If you like, you can think of the Configuration as an object representation of a configuration file (or a properties file) for Hibernate. Let s look at some variations before we wrap it up in the HibernateUtil class.
Copyright © OnBarcode.com . All rights reserved.