storing an objcet with only selected columns

[indu iyengar]

Hi all,

My requirement is store only selected columns in the database for an object using Hibernate...

When i set the values and try to store with desired columns , it s not showing any error, but in the db the object is not updating.

please tell me how to .. ?

[Paul Sturrock]

Can you give us more detail? Perhaps post your code?

[indu iyengar]

thanks for the reply..

Register Student is a pojo with 4 fields

   private long stid;
	private String stpw;
	private String stname;
	private Date dob;

In Register Form.jsp i have only 2 fields

Student Name and DOB

the table in DB is with 4 corresponding columns as in Pojo.

Here I need to store only studentName and DOB in DB(student ID is increment generator) , and in return i need to give studentID for the student .

Mycode to update

              date1 = df1.parse(dob);
			dob = df2.format(date1);
			dbdate = df2.parse(dob);
			System.out.println(" DBDATE ------------>>>>>>>  "+dbdate);
			DBRegisterStudent dbr = new DBRegisterStudent();
			dbr.setStname(reg.getStname());
			dbr.setDob(dbdate);
			session.update(dbr);
			System.out.println(" updated .... ");	///  Database table is not updating..	

[Paul Sturrock]

You will need to load the object you want to update, otherwise Hibernate has no way of knowing what it is you are trying to update.

[indu iyengar]

Thaks Paul for replying... how to load an object without knowing its identifier ? because identifier will be created once the object is stored.. Please tell me is there any other way of doing for this ?

[Paul Sturrock]

how to load an object without knowing its identifier

This cannot be done. You can't find anything in a relational database unless you can identify it.

because identifier will be created once the object is stored

This sounds to me like you are trying to create rather than update an object, is that so? In which case you need to use the save method, not the update method of Session.

[indu iyengar]

yes.. am using save method only..

session.save(dbr);

but object is not creating in database

[Paul Sturrock]

yes.. am using save method only..

Not in the code posted above, have you changed it?

Where do you commit your transaction?

[indu iyengar]

yes.. I changed it to

session.save(reg);

no exception is coming.. but not creating any object in DB

[Paul Sturrock]

Where do you commit your transaction?

[indu iyengar]

oh sorry Paul, I forgot to commit the transaction .. It is storing the object properly...

Thanks a lot..

[Paul Sturrock]

You're welcome