We need some more information about the actual code you were using, how you
are getting the connections, etc. You can get this to work the way you want
to (a single transaction), there is just something off a bit. What
appserver are you using, what database?
Cheers
-----Original Message-----
From: Jeetendra
To: [EMAIL PROTECTED]
Sent: 9/11/01 10:56 AM
Subject: Data Access Patterns
Hello,
We had initiated this discussion a few days ago. I am looking for some
comments on my implementation of this pattern. Here is the description
1) I have a Session bean (as Session Facade) which has a method to open
a
new account (lets call it sf_method1 representing method1 of session
facade). Opening a new account requires us to insert the account
information
in the database and to link this account to a customer.
1.1) The method in Session Facade (sf_method1) calls sb_acct_method1
(method1 of account session bean). This method will insert the account
information in the database. To insert this data it makes use of a data
access object. Say it calls the method dao_method1 where dao_method1
will
insert the data (account information) in the accounts table.
1.1.1) dao_method1 obtains a connection from the connection pool by
looking
up for the data source object (javax.sql.DataSource). It then inserts
the
account information in account_info table
1.2) The next method called by session facade bean is sb_acct_method2
(method2 of the same session bean as in step 1.1) . This method inserts
a
records in Customer_Account table. This table merely contains two
columns -
Customer_Id and Account_Id. Even this method uses the abovementioned DAO
to
insert the data in Customer_Account table. Say it calls dao_method2.
1.2.1) dao_method2 obtains a connection from the pool and inserts the
data
in Customer_Account table.
The question is whether and how do I use declarative transactions?
I have declared the attribute of sf_method1 as REQUIRESNEW and that of
sb_acct_method1 and sb_acct_method2 as REQUIRED.
In the dao_method2 I have a division by zero exception. When I run the
client, the data is inserted in the account_info table (whereas I did
not
expect it because the second part of the transaction namely inserting
into
Customer_Account table) failed .
What I could derive from this is
1) The transactional scope of a method (of a bean) does not extend to
Java
classes that it might be calling.
2) By using DAO patterns, the transaction management becomes the
responsibility of the programmer.
Please let me know if I have got it wrong.
I was also wondering about the usability of this pattern in areas where
we
have only session beans. This ofcourse goes with the assumption that we
cannot extend transactional scope of a bean to the Data Access Objects.
Does
merely seperating the data access logic justify the cost of managing
transactions?
Thanx a lot in anticipation
Jeetendra Dassani
Lead Systems Engineer
Tata Infotech Limited
SEEPZ, Andheri (E)
Mumbai.
Email : [EMAIL PROTECTED]
[EMAIL PROTECTED]
Telephone: 8291261 X 2775/2465
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