Re: [OT] Updating CachedRowSet
RowSet does not do Multi Table Updates! Neither does CommonsSQL as I saw
it. That is why it's light weight, fast and scalable, since it does not
deal with O/R, it is just relational data. For R/O, you can do joins,
most data is R/O. Also, if you do use RowSet, do not use ResultSet, no
need for it. (The reason I use Struts is that is is light weight and
fast, thus I avoid heavy DAO layers that do not do SQL (ex: EJB, JDO, OJB).
For R/W:
But of course one can do master/Detail, or many to many, or more
complicated updates, in fact most updates are "compound". See if I can
explain this, but it takes using the tool between the ears:
For multi table updates I create a nested bean. Master/Detail like.
I always start by creating base beans, simple beans that are unit
tested, and have a dao, but have a singe table.
Then I created a C bean that extends bean A, and has a bean B. (is a/has
a is very OO **)
Bean C has 2 tables now. (you get the idea?) It has a B getB() method. I
override next (for iteration) to go next on the A and B, find {to do
super.find() (for A) and B.find for b }, save { super.save(), B.save()
}, etc.
With this Zero copy approach, I can get very high transactions rates for
low overhead. Compare this to multi copy and ineficient aproach of array
list of objects when you need to do updetable master detail processing.
Why is this Zero copy? Because the cached or disconnected row set, where
the retrieval happens, is where the setters fire. (Advanced: My beans
are actually collections with getRow so they can do multi row updates,
but they look like regular beans).
I can change DAO implementation at will as well. I can use same bean in
console, or Model 1, or Soap, etc. since DAO lets me create a DBCP pool
or use the pool of the container (based on properties).
My Beans of type C are tied to the presentation layer.
OT: (Since my beans of type C are tied to the presentation, I do
presentation first on my projects as a "contract" with 0 code until the
presentation layers is accepted and signed of by a client.
The presentation just has actions that forward to "success", nothing
else, maybe some other navigation logic.
The JSPs the client sees look real, as a finished app. It has tiles, and
CSS, but no java code, no point in coding until the client signs of.
Once the client says, yes, this is the what I want (Just blank actions
and JSP) then I start coding the "simple beans" that I unit test. Then I
create the bus. compound beans (is a/ has a) and unit test them. Thus I
have benefits of layered iterative approach. The thing that I will be
adding soon to "example app" , is more browser side procesing in XFORMS,
and JavaScript.
Consider allways writing presentation and action mappings first in Model
2, then beans come natural. That is why you do MVC layers, right, so you
can unit test each!).
.V
** Some people do not realize that Java is OO capable. Java does not
produce OO reusable code on it's own, it compiles fine linear, but you
could if you have experience make it reusable via OO. This lets me reuse
beans, and other things.
John Bigboote wrote:
Hmm, I think that's implementation dependent. For
example, the Oracle CachedRowSet implementation
doesn't support updating joined tables. See:
http://otn.oracle.com/docs/products/ias/doc_library/90200doc_otn/web.902/a90211/rowset.htm#628357
I don't know for sure, but I'll wager the RI doesn't,
either...
John
--- Jerry Jalenak <[EMAIL PROTECTED]> wrote:
My initial SQL SELECT statement that creates my
ResultSet pulls data from several tables. I wasn't
sure if the RowSetWriter implementation would be
able to accommodate this scenario, so I've started
using the CachedRowSet object as a means of passing
data from DAO to business logic and back. I had to
kill the writer in order to use the
'acceptChanges()'
method. Does the default RowSetWriter handle
updating multiple tables?
Jerry
-Original Message-
From: John Bigboote [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, November 26, 2002 2:23 PM
To: Struts Users Mailing List
Subject: Re: [OT] Updating CachedRowSet
--- Jerry Jalenak <[EMAIL PROTECTED]>
wrote:
[...snip...]
crs.updateString("userInfo", userInfo);
crs.updateRow();
crs.setWriter(null); // kill default writer
crs.acceptChanges();
Why are you setting the writer to null? It's the
RowSetWriter that propagates changes back to the
database...
John
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RE: [OT] Updating CachedRowSet
Hmm, I think that's implementation dependent. For
example, the Oracle CachedRowSet implementation
doesn't support updating joined tables. See:
http://otn.oracle.com/docs/products/ias/doc_library/90200doc_otn/web.902/a90211/rowset.htm#628357
I don't know for sure, but I'll wager the RI doesn't,
either...
John
--- Jerry Jalenak <[EMAIL PROTECTED]> wrote:
>
> My initial SQL SELECT statement that creates my
> ResultSet pulls data from several tables. I wasn't
> sure if the RowSetWriter implementation would be
> able to accommodate this scenario, so I've started
> using the CachedRowSet object as a means of passing
> data from DAO to business logic and back. I had to
> kill the writer in order to use the
'acceptChanges()'
> method. Does the default RowSetWriter handle
> updating multiple tables?
>
> Jerry
>
> > -Original Message-
> > From: John Bigboote [mailto:[EMAIL PROTECTED]]
> > Sent: Tuesday, November 26, 2002 2:23 PM
> > To: Struts Users Mailing List
> > Subject: Re: [OT] Updating CachedRowSet
> >
> >
> >
> > --- Jerry Jalenak <[EMAIL PROTECTED]>
> wrote:
> > >
> > [...snip...]
> > >
> > >
> > > crs.updateString("userInfo", userInfo);
> > > crs.updateRow();
> > > crs.setWriter(null); // kill default writer
> > > crs.acceptChanges();
> > >
> >
> > Why are you setting the writer to null? It's the
> > RowSetWriter that propagates changes back to the
> > database...
> >
> > John
> >
> >
> > __
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> >
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Re: [OT] Updating CachedRowSet
http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/basicportal/basicportal_07/src/basicWebLib/org/commons/DAO/BasicDAOImpl.java
Above has a working DAO implementation that uses RowSet.
The idea is that you can have many implementations using DAO.
(So, next to it is same DAO that uses SQL-Commons. I only use light
weight DAO becuase they have higher performance and mostly zero copy beans).
After you review above, follow up.
.v
Jerry Jalenak wrote:
My initial SQL SELECT statement that creates my ResultSet pulls data from
several tables. I wasn't sure if the RowSetWriter implementation would be
able to accommodate this scenario, so I've started using the CachedRowSet
object as a means of passing data from DAO to business logic and back. I
had to kill the writer in order to use the 'acceptChanges()' method. Does
the default RowSetWriter handle updating multiple tables?
Jerry
-Original Message-
From: John Bigboote [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, November 26, 2002 2:23 PM
To: Struts Users Mailing List
Subject: Re: [OT] Updating CachedRowSet
--- Jerry Jalenak <[EMAIL PROTECTED]> wrote:
[...snip...]
crs.updateString("userInfo", userInfo);
crs.updateRow();
crs.setWriter(null); // kill default writer
crs.acceptChanges();
Why are you setting the writer to null? It's the
RowSetWriter that propagates changes back to the
database...
John
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RE: [OT] Updating CachedRowSet
My initial SQL SELECT statement that creates my ResultSet pulls data from
several tables. I wasn't sure if the RowSetWriter implementation would be
able to accommodate this scenario, so I've started using the CachedRowSet
object as a means of passing data from DAO to business logic and back. I
had to kill the writer in order to use the 'acceptChanges()' method. Does
the default RowSetWriter handle updating multiple tables?
Jerry
> -Original Message-
> From: John Bigboote [mailto:[EMAIL PROTECTED]]
> Sent: Tuesday, November 26, 2002 2:23 PM
> To: Struts Users Mailing List
> Subject: Re: [OT] Updating CachedRowSet
>
>
>
> --- Jerry Jalenak <[EMAIL PROTECTED]> wrote:
> >
> [...snip...]
> >
> >
> > crs.updateString("userInfo", userInfo);
> > crs.updateRow();
> > crs.setWriter(null); // kill default writer
> > crs.acceptChanges();
> >
>
> Why are you setting the writer to null? It's the
> RowSetWriter that propagates changes back to the
> database...
>
> John
>
>
> __
> Do you Yahoo!?
> Yahoo! Mail Plus - Powerful. Affordable. Sign up now.
> http://mailplus.yahoo.com
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Re: [OT] Updating CachedRowSet
--- Jerry Jalenak <[EMAIL PROTECTED]> wrote:
>
[...snip...]
>
>
> crs.updateString("userInfo", userInfo);
> crs.updateRow();
> crs.setWriter(null); // kill default writer
> crs.acceptChanges();
>
Why are you setting the writer to null? It's the
RowSetWriter that propagates changes back to the
database...
John
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Re: [OT] Updating CachedRowSet
Sorry I don't know how to fix your problem but I do have some comments. It
looks like your DAO class has a bunch of static methods. It's better to
have your DAOs be singletons and be created with a DaoFactory. This allows
various DAO implementations to be plugged in later. You lose this benefit
when using static methods.
David
From: "Jerry Jalenak" <[EMAIL PROTECTED]>
Reply-To: "Struts Users Mailing List" <[EMAIL PROTECTED]>
To: "'[EMAIL PROTECTED]'" <[EMAIL PROTECTED]>
Subject: [OT] Updating CachedRowSet
Date: Tue, 26 Nov 2002 13:46:19 -0600
I'm stumped.
In my DAO I return a disconnected CachedRowSet object back to my business
logic level, do some processing, then update the CachedRowSet so I can send
it back to my DAO and update my database. The code basically looks like
this:
CachedRowSet crs = new CachedRowSet();
try {
crs = DAO.findUserProfile(user);
do stuff
crs.updateString("userInfo", userInfo);
crs.updateRow();
crs.setWriter(null); /* kill the default writer
*/
crs.acceptChanges();
DAO.updateUserProfile(crs);
}
I can print out the updated userInfo and see that it has been changed. But
when I print out the contents of the 'userInfo' column from the
CachedRowSet, it still has the original values. I think it has something
to
do with not being on the correct row, but all of the doc I can find leads
me
to believe that the code above should work. Does anyone have any ideas why
this doesn't?
TIA!
Jerry Jalenak
Web Publishing
LabOne, Inc.
10101 Renner Blvd.
Lenexa, KS 66219
(913) 577-1496
[EMAIL PROTECTED]
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