Home » Modeling » EMF » Are CDO Transactions transparents?
|
| Re: Are CDO Transactions transparents? [message #419654 is a reply to message #419649] |
Sat, 31 May 2008 01:30   |
Eclipse User |
|
|
|
Originally posted by: cdamus.zeligsoft.com
--=-GYz6lye4f3cNoZvL49Xs
Content-Type: text/plain
Content-Transfer-Encoding: 7bit
Hi, AJ,
I think your first question wants to be asked on the EMFT newsgroup,
where CDO lives.
There is no relationship between the
org.eclipse.emf.transaction.Transaction and a CDO transaction. A CDO
transaction has many of the characteristics of transactions in a
relational database management system: atomicity, concurrency,
isolation, and durability. Indeed, in the most common case, a CDO
transaction is actually backed by an RDBMS transaction.
The transactions of the EMF Transaction component have none of these
characteristics. Rather, these transactions are a relatively simply
mechanism for guarding concurrent access to EMF data, with some data
integrity facilities (validation, triggers, and rollback) that are
inspired by, but by no means as robust as, database transactions. It is
a practical approach to building robust editors on EMF models in a
concurrent Eclipse environment, but is not a technology for integration
with EIS or anything like that.
HTH,
Christian
On Fri, 2008-05-30 at 22:26 +0000, AJ wrote:
> Hi,
>
> According to Eike Stepper (see link to post below), transactions are
> transparent and we don't need to worry about them when editing our EMF
> model. If that's the case, how do we control transactions when we need to,
> for instance, say I change several fields in a model, but don't want to
> have them sent over the wire until I hit the "save" button?
>
> http://dev.eclipse.org/newslists/news.eclipse.tools.emf/msg1 1555.html
>
> Also, I notice that CDOTransaction doesn't seem to have anything to do
> with org.eclipse.emf.transaction.Transaction; what's the relationship
> between them, if any?
>
> Thanks in advance!
>
>
--=-GYz6lye4f3cNoZvL49Xs
Content-Type: text/html; charset=utf-8
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 TRANSITIONAL//EN">
<HTML>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=UTF-8">
<META NAME="GENERATOR" CONTENT="GtkHTML/3.16.0">
</HEAD>
<BODY>
Hi, AJ,<BR>
<BR>
I think your first question wants to be asked on the EMFT newsgroup, where CDO lives.<BR>
<BR>
There is no relationship between the org.eclipse.emf.transaction.Transaction and a CDO transaction. A CDO transaction has many of the characteristics of transactions in a relational database management system: atomicity, concurrency, isolation, and durability. Indeed, in the most common case, a CDO transaction is actually backed by an RDBMS transaction.<BR>
<BR>
The transactions of the EMF Transaction component have none of these characteristics. Rather, these transactions are a relatively simply mechanism for guarding concurrent access to EMF data, with some data integrity facilities (validation, triggers, and rollback) that are inspired by, but by no means as robust as, database transactions. It is a practical approach to building robust editors on EMF models in a concurrent Eclipse environment, but is not a technology for integration with EIS or anything like that.<BR>
<BR>
HTH,<BR>
<BR>
Christian<BR>
<BR>
<BR>
On Fri, 2008-05-30 at 22:26 +0000, AJ wrote:
<BLOCKQUOTE TYPE=CITE>
<PRE>
<FONT COLOR="#000000">Hi,</FONT>
<FONT COLOR="#000000">According to Eike Stepper (see link to post below), transactions are </FONT>
<FONT COLOR="#000000">transparent and we don't need to worry about them when editing our EMF </FONT>
<FONT COLOR="#000000">model. If that's the case, how do we control transactions when we need to, </FONT>
<FONT COLOR="#000000">for instance, say I change several fields in a model, but don't want to </FONT>
<FONT COLOR="#000000">have them sent over the wire until I hit the "save" button?</FONT>
<FONT COLOR="#000000"><A HREF=" http://dev.eclipse.org/newslists/news.eclipse.tools.emf/msg1 1555.html"> http://dev.eclipse.org/newslists/news.eclipse.tools.emf/msg1 1555.html</A></FONT>
<FONT COLOR="#000000">Also, I notice that CDOTransaction doesn't seem to have anything to do </FONT>
<FONT COLOR="#000000">with org.eclipse.emf.transaction.Transaction; what's the relationship </FONT>
<FONT COLOR="#000000">between them, if any?</FONT>
<FONT COLOR="#000000">Thanks in advance!</FONT>
</PRE>
</BLOCKQUOTE>
</BODY>
</HTML>
--=-GYz6lye4f3cNoZvL49Xs--
|
|
| | |
| Re: Are CDO Transactions transparents? [message #419665 is a reply to message #419656] |
Sat, 31 May 2008 19:01 |
| Eclipse User |
|
|
|
Originally posted by: cdamus.zeligsoft.com
--=-bJ4z6j8jHaFQ39DFWD6O
Content-Type: text/plain
Content-Transfer-Encoding: 7bit
Sorry, AJ. The confusion is mine. I missed that announcement.
cW
On Sat, 2008-05-31 at 03:25 +0000, AJ wrote:
> Hi, Christian,
>
> Thank you for answering the 2nd question. I will post the 1st on the EMFT
> newsgroup. I guess I was confused by the announcement on the EMFT pages
> saying "CDO has graduated to Eclipse Modeling Framework (EMF)."; which is
> now listed here:
>
> http://www.eclipse.org/modeling/emf/?project=cdo#cdo
>
> Thanks & best regards,
> -AJ
>
>
>
--=-bJ4z6j8jHaFQ39DFWD6O
Content-Type: text/html; charset=utf-8
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 TRANSITIONAL//EN">
<HTML>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=UTF-8">
<META NAME="GENERATOR" CONTENT="GtkHTML/3.16.0">
</HEAD>
<BODY>
Sorry, AJ. The confusion is mine. I missed that announcement.<BR>
<BR>
cW<BR>
<BR>
On Sat, 2008-05-31 at 03:25 +0000, AJ wrote:
<BLOCKQUOTE TYPE=CITE>
<PRE>
<FONT COLOR="#000000">Hi, Christian,</FONT>
<FONT COLOR="#000000">Thank you for answering the 2nd question. I will post the 1st on the EMFT </FONT>
<FONT COLOR="#000000">newsgroup. I guess I was confused by the announcement on the EMFT pages </FONT>
<FONT COLOR="#000000">saying "CDO has graduated to Eclipse Modeling Framework (EMF)."; which is </FONT>
<FONT COLOR="#000000">now listed here:</FONT>
<FONT COLOR="#000000"><A HREF="http://www.eclipse.org/modeling/emf/?project=cdo#cdo">http://www.eclipse.org/modeling/emf/?project=cdo#cdo</A></FONT>
<FONT COLOR="#000000">Thanks & best regards,</FONT>
<FONT COLOR="#000000">-AJ</FONT>
</PRE>
</BLOCKQUOTE>
</BODY>
</HTML>
--=-bJ4z6j8jHaFQ39DFWD6O--
|
|
|
| Re: Are CDO Transactions transparents? [message #419668 is a reply to message #419649] |
Sun, 01 June 2008 08:31 |
|
Hi AJ,
As Chris said, there's no technical relationship between a
CDOTransaction and an org.eclipse.emf.transaction.Transaction.
Obviously both try to solve a similar problem, so the next question is:
How do they differ in that?
Functionally Chris' explanation of the differences is correct: A
CDOTransaction operates on EObjects (well, on CDOObjectImpls) while
Chris' transactions operate on resources. They have different locking
granularities.
From an architecture point of view the main difference is that a
CDOTransaction operates at the model layer whereas Chris' transaction
operates at the model.edit layer. As Chris said, his solution requires
the cooperation of *all* editors (edit-clients) that use the model. With
a CDOTransaction this is not necessary because the transactionality is
transparent to the model.edit and the model.editor. Even a model-client
that doesn't use the edit framework at all would be able to participate
in transactions.
Cheers
/Eike
AJ schrieb:
> Hi,
>
> According to Eike Stepper (see link to post below), transactions are
> transparent and we don't need to worry about them when editing our EMF
> model. If that's the case, how do we control transactions when we need
> to, for instance, say I change several fields in a model, but don't
> want to have them sent over the wire until I hit the "save" button?
>
> http://dev.eclipse.org/newslists/news.eclipse.tools.emf/msg1 1555.html
>
> Also, I notice that CDOTransaction doesn't seem to have anything to do
> with org.eclipse.emf.transaction.Transaction; what's the relationship
> between them, if any?
>
> Thanks in advance!
>
>
Cheers
/Eike
----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper
|
|
|
Goto Forum:
Current Time: Fri Apr 26 15:19:12 GMT 2024
Powered by FUDForum. Page generated in 0.03777 seconds |
] 
Search
Help
Register
Login
Home
