How do I 'UPDATE' using EJB

[Tiago Sudeval]

Hi,
Someone can help me, how i do a update using EJB, something similar with 'source' below.

...
 
* @ejb.finder signature="UidGenLocal findByName(java.lang.String name)"
*query="SELECT OBJECT(c) FROM UidGen AS c WHERE c.name=?1"

using SQL:

"UPDATE UidGen SET value=value+1 WHERE name=?"

or don't possible?

ps.: EJB is EntityBean
[ November 10, 2006: Message edited by: sudeval ]

[Prabhu Venkatachalam]

Why do you want to update in EJB QL?

Steps for UPDATING :

1. Get the particular entity bean(in DB it is a row) using its primary key.

2. Using Bean's Component Interface implemented object, change the value using setter methods.

3. Once done, If it is CMP, container will UPDATE the database. If it is BMP, then you need to write a query in ejbLoad to do the updation.

There is no support for updating in EJB QL and even it doesn't make any sense in this context.

HTH,

[Mark Spritzler]

"sudeval",
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[Tiago Sudeval]

Originally posted by Prabhu venkatachalam:
Why do you want to update in EJB QL?

Steps for UPDATING :

1. Get the particular entity bean(in DB it is a row) using its primary key.

2. Using Bean's Component Interface implemented object, change the value using setter methods.

3. Once done, If it is CMP, container will UPDATE the database. If it is BMP, then you need to write a query in ejbLoad to do the updation.

There is no support for updating in EJB QL and even it doesn't make any sense in this context.

HTH,

ok, but how do i using ejbLoad() ?

do you have one example ?

Why do you want to update in EJB QL?

because i need performace, and in my source is this:

/**
 * @ejb.create-method
 */
public String ejbCreate(String name)
throws javax.ejb.CreateException {
setName(name);
setValue(1);
return null;
}

/**
 * @ejb.interface-method
 */
 public int nextValue() {
int value = getValue();
setValue(value + 1);
return value;
 }

/**
 * @ejb.interface-method
 */
public static int nextValue(String name) throws CreateException, NamingException {
UidGenLocalHome h=null;
UidGenLocal l=null;
try {
h = UidGenUtil.getLocalHome();
l = h.findByName(name);
} catch(FinderException e) {
l=h.create(name);
}
return l.nextValue();
}

Using this source i don't has perfomace becaouse i get the connection (Transaction) and get the value, after i get other connection to update the value.

i need the something as a "SELECT ... FOR UPDATE" where i using one connection(transaction) get the value e update this value.

do you understands?

thanks!