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Posted to torque-user@db.apache.org by Joacim Turesson <jo...@profuture.se> on 2004/03/09 10:35:11 UTC
[Newbie] Getting limited number of rows
Hi!
I'm using Torque and it works fine:-)
I'm working with a webbapplication and I want to display a limited
amount of a data in a list.
How do I get a limited number of rows, and still knows how many total
number of rows there exist?
As I understand:
* setOffset indicates from where I start (zero based)
* setLimit indicates how many rows from the offset I get
Do I have to do a select count statement with the criteria above without
offset and limit to get the total number of rows?
Or is it a better way?
Best Regards
Joacim Turesson
Re: Further question [Newbie] Getting limited number of rows
Posted by Scott Eade <se...@backstagetech.com.au>.
Bogdan is correct - you would customise the indicated methods if you were selecting just a subset of the columns (which would be good for performance if you only need a subset of the columns defined in the table) or if you are selecting columns from multiple tables into one object.
Scott
--
Scott Eade
Backstage Technologies Pty. Ltd.
http://www.backstagetech.com.au
Bogdan Vatkov wrote:
>Hi,
>I am not sure but i think this customization might be usefull when selecting
>a large amount of rows
>in cases where you are not going to extract well specified torque DataObject
>but a Select statement
>created on the fly ...for example JOIN of 2-3-4 different tables ...then you
>do not have torque object to represent the selected columns ..hope this
>gives some answers ..
>
>Regards,
>Bogdan
>----- Original Message -----
>From: "bhiyavudh" <bh...@hotmail.com>
>To: "Apache Torque Users List" <to...@db.apache.org>
>Sent: Tuesday, March 09, 2004 5:10 PM
>Subject: Further question [Newbie] Getting limited number of rows
>
>
>
>
>>Hi all,
>> A further question on LargeSelect. I have try your sample with my data
>>and it work ok, just check on the API doc and it mentions that you can
>>customize "addSelectColumns() , populateObjects(), row2Object() and
>>populateObject() methods from an existing Peer class". I am not sure why
>>would we need to customize these methods because with the default
>>implementation it already copy data from the list of village records to
>>
>>
>list
>
>
>>of object we need (the one we passed to LargeSelect constructor as
>>returnBuilderClassName).Any specific reason for customization. Is it
>>intended for your own implementation of the business object, not the one
>>generated by torque. Sorry I am not quite sure what exactly does it mean.
>>Regards,
>>
>>----- Original Message -----
>>From: "Bogdan Vatkov" <bv...@globaltech-bg.com>
>>To: "Apache Torque Users List" <to...@db.apache.org>
>>Sent: Tuesday, March 09, 2004 11:11 AM
>>Subject: Re: [Newbie] Getting limited number of rows
>>
>>
>>
>>
>>>Hi Joacim,
>>>
>>>I think the best way to do the thing you are trying to do is to use
>>>LargeSelect
>>>it provides more functionality than just number of rows limitation.
>>>It gives you the paged tables that almost every weblication needs.
>>>Actually using LargeSelect you are not responsible for the SQL statement
>>>/( Criteria preparation) for limiting the rows anymore.
>>>I am using it and it is quite good ..in fact it has all that I need.
>>>
>>>1) display single page of a db table (example 10 rows)
>>>2) display the navigation info (example "page 3 of 10 total")
>>>3) and of course methods for first/prev/next/last pages
>>>4) the LargeSelect class provides customization of the number of rows to
>>>
>>>
>>be
>>
>>
>>>fetched..and numbers of rows to be displayed in a single page
>>>
>>>
>>>example from my code: (there is some of my local logic ..like
>>>
>>>
>weblication
>
>
>>>action object ..but i think you will get the idea of using the
>>>
>>>
>LargeSelect
>
>
>>>object)
>>>
>>>load the data:
>>>
>>> private static final int PAGE_SIZE = 10; // maximum page size
>>> private static final int PAGES_FETCH_COUNT = 10; // pages to be loaded
>>>
>>>
>>on
>>
>>
>>>time
>>>
>>> private void LoadLargeSelect(Criteria parameter) {
>>> largeSelect = new LargeSelect(parameter, PAGE_SIZE,
>>>
>>>
>PAGES_FETCH_COUNT,
>
>
>>> CsVpbxPeer.class.getName());
>>> try {
>>> largeSelect.getNextResults();
>>> }
>>> catch (Exception e) {
>>> logError(e);
>>> }
>>> }
>>>
>>>
>>>weblication actions interpret:
>>>
>>>
>>> if (action.equals(Action.COMMON_LIST_FIRST_PAGE)) {
>>> businessObjectList = largeSelect.getPage(1);
>>> }
>>> else if (action.equals(Action.COMMON_LIST_LAST_PAGE)) {
>>> businessObjectList =
>>>largeSelect.getPage(largeSelect.getTotalPages());
>>> }
>>> else if (action.equals(Action.COMMON_LIST_NEXT_PAGE)) {
>>> businessObjectList = largeSelect.getNextResults();
>>> }
>>> else if (action.equals(Action.COMMON_LIST_PREV_PAGE)) {
>>> businessObjectList = largeSelect.getPreviousResults();
>>> }
>>> else {
>>> largeSelect.invalidateResult();
>>> businessObjectList = largeSelect.getPage(1);
>>> }
>>>
>>>I am not sure that it is what you need but is a good start point.
>>>
>>>With best regards,
>>>Bogdan Vatkov
>>>
>>>----- Original Message -----
>>>From: "Joacim Turesson" <jo...@profuture.se>
>>>To: <to...@db.apache.org>
>>>Sent: Tuesday, March 09, 2004 11:35 AM
>>>Subject: [Newbie] Getting limited number of rows
>>>
>>>
>>>
>>>
>>>>Hi!
>>>>
>>>>
>>>>
>>>>I'm using Torque and it works fine:-)
>>>>
>>>>
>>>>
>>>>I'm working with a webbapplication and I want to display a limited
>>>>amount of a data in a list.
>>>>
>>>>
>>>>
>>>>How do I get a limited number of rows, and still knows how many total
>>>>number of rows there exist?
>>>>
>>>>
>>>>
>>>>As I understand:
>>>>
>>>>* setOffset indicates from where I start (zero based)
>>>>* setLimit indicates how many rows from the offset I get
>>>>
>>>>
>>>>
>>>>Do I have to do a select count statement with the criteria above
>>>>
>>>>
>without
>
>
>>>>offset and limit to get the total number of rows?
>>>>
>>>>Or is it a better way?
>>>>
>>>>
>>>>
>>>>Best Regards
>>>>
>>>>
>>>>
>>>>Joacim Turesson
>>>>
>>>>
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Re: Further question [Newbie] Getting limited number of rows
Posted by Bogdan Vatkov <bv...@globaltech-bg.com>.
Hi,
I am not sure but i think this customization might be usefull when selecting
a large amount of rows
in cases where you are not going to extract well specified torque DataObject
but a Select statement
created on the fly ...for example JOIN of 2-3-4 different tables ...then you
do not have torque object to represent the selected columns ..hope this
gives some answers ..
Regards,
Bogdan
----- Original Message -----
From: "bhiyavudh" <bh...@hotmail.com>
To: "Apache Torque Users List" <to...@db.apache.org>
Sent: Tuesday, March 09, 2004 5:10 PM
Subject: Further question [Newbie] Getting limited number of rows
> Hi all,
> A further question on LargeSelect. I have try your sample with my data
> and it work ok, just check on the API doc and it mentions that you can
> customize "addSelectColumns() , populateObjects(), row2Object() and
> populateObject() methods from an existing Peer class". I am not sure why
> would we need to customize these methods because with the default
> implementation it already copy data from the list of village records to
list
> of object we need (the one we passed to LargeSelect constructor as
> returnBuilderClassName).Any specific reason for customization. Is it
> intended for your own implementation of the business object, not the one
> generated by torque. Sorry I am not quite sure what exactly does it mean.
> Regards,
>
> ----- Original Message -----
> From: "Bogdan Vatkov" <bv...@globaltech-bg.com>
> To: "Apache Torque Users List" <to...@db.apache.org>
> Sent: Tuesday, March 09, 2004 11:11 AM
> Subject: Re: [Newbie] Getting limited number of rows
>
>
> > Hi Joacim,
> >
> > I think the best way to do the thing you are trying to do is to use
> > LargeSelect
> > it provides more functionality than just number of rows limitation.
> > It gives you the paged tables that almost every weblication needs.
> > Actually using LargeSelect you are not responsible for the SQL statement
> > /( Criteria preparation) for limiting the rows anymore.
> > I am using it and it is quite good ..in fact it has all that I need.
> >
> > 1) display single page of a db table (example 10 rows)
> > 2) display the navigation info (example "page 3 of 10 total")
> > 3) and of course methods for first/prev/next/last pages
> > 4) the LargeSelect class provides customization of the number of rows to
> be
> > fetched..and numbers of rows to be displayed in a single page
> >
> >
> > example from my code: (there is some of my local logic ..like
weblication
> > action object ..but i think you will get the idea of using the
LargeSelect
> > object)
> >
> > load the data:
> >
> > private static final int PAGE_SIZE = 10; // maximum page size
> > private static final int PAGES_FETCH_COUNT = 10; // pages to be loaded
> on
> > time
> >
> > private void LoadLargeSelect(Criteria parameter) {
> > largeSelect = new LargeSelect(parameter, PAGE_SIZE,
PAGES_FETCH_COUNT,
> > CsVpbxPeer.class.getName());
> > try {
> > largeSelect.getNextResults();
> > }
> > catch (Exception e) {
> > logError(e);
> > }
> > }
> >
> >
> > weblication actions interpret:
> >
> >
> > if (action.equals(Action.COMMON_LIST_FIRST_PAGE)) {
> > businessObjectList = largeSelect.getPage(1);
> > }
> > else if (action.equals(Action.COMMON_LIST_LAST_PAGE)) {
> > businessObjectList =
> > largeSelect.getPage(largeSelect.getTotalPages());
> > }
> > else if (action.equals(Action.COMMON_LIST_NEXT_PAGE)) {
> > businessObjectList = largeSelect.getNextResults();
> > }
> > else if (action.equals(Action.COMMON_LIST_PREV_PAGE)) {
> > businessObjectList = largeSelect.getPreviousResults();
> > }
> > else {
> > largeSelect.invalidateResult();
> > businessObjectList = largeSelect.getPage(1);
> > }
> >
> > I am not sure that it is what you need but is a good start point.
> >
> > With best regards,
> > Bogdan Vatkov
> >
> > ----- Original Message -----
> > From: "Joacim Turesson" <jo...@profuture.se>
> > To: <to...@db.apache.org>
> > Sent: Tuesday, March 09, 2004 11:35 AM
> > Subject: [Newbie] Getting limited number of rows
> >
> >
> > > Hi!
> > >
> > >
> > >
> > > I'm using Torque and it works fine:-)
> > >
> > >
> > >
> > > I'm working with a webbapplication and I want to display a limited
> > > amount of a data in a list.
> > >
> > >
> > >
> > > How do I get a limited number of rows, and still knows how many total
> > > number of rows there exist?
> > >
> > >
> > >
> > > As I understand:
> > >
> > > * setOffset indicates from where I start (zero based)
> > > * setLimit indicates how many rows from the offset I get
> > >
> > >
> > >
> > > Do I have to do a select count statement with the criteria above
without
> > > offset and limit to get the total number of rows?
> > >
> > > Or is it a better way?
> > >
> > >
> > >
> > > Best Regards
> > >
> > >
> > >
> > > Joacim Turesson
> > >
> > >
> > >
> > >
> >
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: torque-user-unsubscribe@db.apache.org
> > For additional commands, e-mail: torque-user-help@db.apache.org
> >
> >
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: torque-user-unsubscribe@db.apache.org
> For additional commands, e-mail: torque-user-help@db.apache.org
>
---------------------------------------------------------------------
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Further question [Newbie] Getting limited number of rows
Posted by bhiyavudh <bh...@hotmail.com>.
Hi all,
A further question on LargeSelect. I have try your sample with my data
and it work ok, just check on the API doc and it mentions that you can
customize "addSelectColumns() , populateObjects(), row2Object() and
populateObject() methods from an existing Peer class". I am not sure why
would we need to customize these methods because with the default
implementation it already copy data from the list of village records to list
of object we need (the one we passed to LargeSelect constructor as
returnBuilderClassName).Any specific reason for customization. Is it
intended for your own implementation of the business object, not the one
generated by torque. Sorry I am not quite sure what exactly does it mean.
Regards,
----- Original Message -----
From: "Bogdan Vatkov" <bv...@globaltech-bg.com>
To: "Apache Torque Users List" <to...@db.apache.org>
Sent: Tuesday, March 09, 2004 11:11 AM
Subject: Re: [Newbie] Getting limited number of rows
> Hi Joacim,
>
> I think the best way to do the thing you are trying to do is to use
> LargeSelect
> it provides more functionality than just number of rows limitation.
> It gives you the paged tables that almost every weblication needs.
> Actually using LargeSelect you are not responsible for the SQL statement
> /( Criteria preparation) for limiting the rows anymore.
> I am using it and it is quite good ..in fact it has all that I need.
>
> 1) display single page of a db table (example 10 rows)
> 2) display the navigation info (example "page 3 of 10 total")
> 3) and of course methods for first/prev/next/last pages
> 4) the LargeSelect class provides customization of the number of rows to
be
> fetched..and numbers of rows to be displayed in a single page
>
>
> example from my code: (there is some of my local logic ..like weblication
> action object ..but i think you will get the idea of using the LargeSelect
> object)
>
> load the data:
>
> private static final int PAGE_SIZE = 10; // maximum page size
> private static final int PAGES_FETCH_COUNT = 10; // pages to be loaded
on
> time
>
> private void LoadLargeSelect(Criteria parameter) {
> largeSelect = new LargeSelect(parameter, PAGE_SIZE, PAGES_FETCH_COUNT,
> CsVpbxPeer.class.getName());
> try {
> largeSelect.getNextResults();
> }
> catch (Exception e) {
> logError(e);
> }
> }
>
>
> weblication actions interpret:
>
>
> if (action.equals(Action.COMMON_LIST_FIRST_PAGE)) {
> businessObjectList = largeSelect.getPage(1);
> }
> else if (action.equals(Action.COMMON_LIST_LAST_PAGE)) {
> businessObjectList =
> largeSelect.getPage(largeSelect.getTotalPages());
> }
> else if (action.equals(Action.COMMON_LIST_NEXT_PAGE)) {
> businessObjectList = largeSelect.getNextResults();
> }
> else if (action.equals(Action.COMMON_LIST_PREV_PAGE)) {
> businessObjectList = largeSelect.getPreviousResults();
> }
> else {
> largeSelect.invalidateResult();
> businessObjectList = largeSelect.getPage(1);
> }
>
> I am not sure that it is what you need but is a good start point.
>
> With best regards,
> Bogdan Vatkov
>
> ----- Original Message -----
> From: "Joacim Turesson" <jo...@profuture.se>
> To: <to...@db.apache.org>
> Sent: Tuesday, March 09, 2004 11:35 AM
> Subject: [Newbie] Getting limited number of rows
>
>
> > Hi!
> >
> >
> >
> > I'm using Torque and it works fine:-)
> >
> >
> >
> > I'm working with a webbapplication and I want to display a limited
> > amount of a data in a list.
> >
> >
> >
> > How do I get a limited number of rows, and still knows how many total
> > number of rows there exist?
> >
> >
> >
> > As I understand:
> >
> > * setOffset indicates from where I start (zero based)
> > * setLimit indicates how many rows from the offset I get
> >
> >
> >
> > Do I have to do a select count statement with the criteria above without
> > offset and limit to get the total number of rows?
> >
> > Or is it a better way?
> >
> >
> >
> > Best Regards
> >
> >
> >
> > Joacim Turesson
> >
> >
> >
> >
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: torque-user-unsubscribe@db.apache.org
> For additional commands, e-mail: torque-user-help@db.apache.org
>
>
---------------------------------------------------------------------
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SV: [Newbie] Getting limited number of rows
Posted by Joacim Turesson <jo...@profuture.se>.
Thanks!
It works great!
/Joacim Turesson
-----Ursprungligt meddelande-----
Från: Bogdan Vatkov [mailto:bvatkov@globaltech-bg.com]
Skickat: den 9 mars 2004 11:11
Till: Apache Torque Users List
Ämne: Re: [Newbie] Getting limited number of rows
Hi Joacim,
I think the best way to do the thing you are trying to do is to use
LargeSelect
it provides more functionality than just number of rows limitation.
It gives you the paged tables that almost every weblication needs.
Actually using LargeSelect you are not responsible for the SQL statement
/( Criteria preparation) for limiting the rows anymore.
I am using it and it is quite good ..in fact it has all that I need.
1) display single page of a db table (example 10 rows)
2) display the navigation info (example "page 3 of 10 total")
3) and of course methods for first/prev/next/last pages
4) the LargeSelect class provides customization of the number of rows to
be
fetched..and numbers of rows to be displayed in a single page
example from my code: (there is some of my local logic ..like
weblication
action object ..but i think you will get the idea of using the
LargeSelect
object)
load the data:
private static final int PAGE_SIZE = 10; // maximum page size
private static final int PAGES_FETCH_COUNT = 10; // pages to be loaded
on
time
private void LoadLargeSelect(Criteria parameter) {
largeSelect = new LargeSelect(parameter, PAGE_SIZE,
PAGES_FETCH_COUNT,
CsVpbxPeer.class.getName());
try {
largeSelect.getNextResults();
}
catch (Exception e) {
logError(e);
}
}
weblication actions interpret:
if (action.equals(Action.COMMON_LIST_FIRST_PAGE)) {
businessObjectList = largeSelect.getPage(1);
}
else if (action.equals(Action.COMMON_LIST_LAST_PAGE)) {
businessObjectList =
largeSelect.getPage(largeSelect.getTotalPages());
}
else if (action.equals(Action.COMMON_LIST_NEXT_PAGE)) {
businessObjectList = largeSelect.getNextResults();
}
else if (action.equals(Action.COMMON_LIST_PREV_PAGE)) {
businessObjectList = largeSelect.getPreviousResults();
}
else {
largeSelect.invalidateResult();
businessObjectList = largeSelect.getPage(1);
}
I am not sure that it is what you need but is a good start point.
With best regards,
Bogdan Vatkov
----- Original Message -----
From: "Joacim Turesson" <jo...@profuture.se>
To: <to...@db.apache.org>
Sent: Tuesday, March 09, 2004 11:35 AM
Subject: [Newbie] Getting limited number of rows
> Hi!
>
>
>
> I'm using Torque and it works fine:-)
>
>
>
> I'm working with a webbapplication and I want to display a limited
> amount of a data in a list.
>
>
>
> How do I get a limited number of rows, and still knows how many total
> number of rows there exist?
>
>
>
> As I understand:
>
> * setOffset indicates from where I start (zero based)
> * setLimit indicates how many rows from the offset I get
>
>
>
> Do I have to do a select count statement with the criteria above
without
> offset and limit to get the total number of rows?
>
> Or is it a better way?
>
>
>
> Best Regards
>
>
>
> Joacim Turesson
>
>
>
>
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---------------------------------------------------------------------
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Re: [Newbie] Getting limited number of rows
Posted by Bogdan Vatkov <bv...@globaltech-bg.com>.
Hi Joacim,
I think the best way to do the thing you are trying to do is to use
LargeSelect
it provides more functionality than just number of rows limitation.
It gives you the paged tables that almost every weblication needs.
Actually using LargeSelect you are not responsible for the SQL statement
/( Criteria preparation) for limiting the rows anymore.
I am using it and it is quite good ..in fact it has all that I need.
1) display single page of a db table (example 10 rows)
2) display the navigation info (example "page 3 of 10 total")
3) and of course methods for first/prev/next/last pages
4) the LargeSelect class provides customization of the number of rows to be
fetched..and numbers of rows to be displayed in a single page
example from my code: (there is some of my local logic ..like weblication
action object ..but i think you will get the idea of using the LargeSelect
object)
load the data:
private static final int PAGE_SIZE = 10; // maximum page size
private static final int PAGES_FETCH_COUNT = 10; // pages to be loaded on
time
private void LoadLargeSelect(Criteria parameter) {
largeSelect = new LargeSelect(parameter, PAGE_SIZE, PAGES_FETCH_COUNT,
CsVpbxPeer.class.getName());
try {
largeSelect.getNextResults();
}
catch (Exception e) {
logError(e);
}
}
weblication actions interpret:
if (action.equals(Action.COMMON_LIST_FIRST_PAGE)) {
businessObjectList = largeSelect.getPage(1);
}
else if (action.equals(Action.COMMON_LIST_LAST_PAGE)) {
businessObjectList =
largeSelect.getPage(largeSelect.getTotalPages());
}
else if (action.equals(Action.COMMON_LIST_NEXT_PAGE)) {
businessObjectList = largeSelect.getNextResults();
}
else if (action.equals(Action.COMMON_LIST_PREV_PAGE)) {
businessObjectList = largeSelect.getPreviousResults();
}
else {
largeSelect.invalidateResult();
businessObjectList = largeSelect.getPage(1);
}
I am not sure that it is what you need but is a good start point.
With best regards,
Bogdan Vatkov
----- Original Message -----
From: "Joacim Turesson" <jo...@profuture.se>
To: <to...@db.apache.org>
Sent: Tuesday, March 09, 2004 11:35 AM
Subject: [Newbie] Getting limited number of rows
> Hi!
>
>
>
> I'm using Torque and it works fine:-)
>
>
>
> I'm working with a webbapplication and I want to display a limited
> amount of a data in a list.
>
>
>
> How do I get a limited number of rows, and still knows how many total
> number of rows there exist?
>
>
>
> As I understand:
>
> * setOffset indicates from where I start (zero based)
> * setLimit indicates how many rows from the offset I get
>
>
>
> Do I have to do a select count statement with the criteria above without
> offset and limit to get the total number of rows?
>
> Or is it a better way?
>
>
>
> Best Regards
>
>
>
> Joacim Turesson
>
>
>
>
---------------------------------------------------------------------
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