Curt,
I think 'dynamic criteria of a DO beiing sessionized as user session object' makes
more sense. Let's consider a simple case- a page having a list box populated by a DO
whose dyn. criteria
is set during onBeforeDisplay event of the page. Now if dyn.
criteria were not to be sessionized & let's say some other user
changed the it right after the display of my page and 2 min.
later I refreshed my page, the contents of the list box would
change and that wouldn't be very nice of ND.
Hope this makes sense
Vishal
Curt Springer <[EMAIL PROTECTED]> wrote:
>Well, now I'm confused.
>
>The below was always my understanding. Then, the last time that Team ND
>got together, back in February, I mentioned this to Brendan, who thought
>otherwise. He whipped up a little test project that seemed to prove this
>wrong. At that point, I figured that my reliance on so-called sessioning
>was where I was setting criteria in a DO in a button or href event method,
>and then executing it after loading another page, but in the same web
>event. Stuff in the same web event doesn't really use sessioning, even if
>your use put/get(Any)UserSessionObject (as discussed in another thread, or
>is it this one, can't keep track).
>
>OK, I will have to do my own test project, and report the results.
>
>-- Curt Springer, Team ND
>
>At 03:09 PM 5/21/99 -0500, Shamdasani Nimmi-ANS004 wrote:
>>Aby,
>>
>>Is this what you are looking for?
>>
>>-Nimmi
>>
>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D> =20
>>Class spider.database.$Package_Description$
>>
>>
>>The WHERE Clause
>>
>>
>>SELECT, UPDATE, and DELETE queries allow (and often require) that you
>>specify
>>criteria. The criteria define the subset of the database records to be
>>retrieved
>>or affected. The criteria are specified in the WHERE clause of the query. A
>>common base class named CSpCriteriaSQLObject provides common functions for
>>constructing queries and defines constant values.
>>
>>
>>In order to support the 4GL functionality NetDynamics provides, the final
>>WHERE
>>clause (when automatically created) is constructed from 5 sub-elements:
>>
>>
>>=B7 Static Join - The joins you specify in the Studio for this data object
>>using
>>the Joins tab of the data object editor
>>
>>=B7 Static Filter - The where criteria you specify in the Studio for this
>>data
>>object using the Where tab of the data object editor
>>
>>=B7 QBE Dynamic Criteria - The criteria automatically added by the doQBE()
>>method
>>(or manually added by you)
>>
>>=B7 DrillDown Dynamic Criteria - The criteria automatically added in some
>>cases by
>>the doAction() method (or manually added by you)
>>
>>=B7 Join Dynamic Criteria - All criteria automatically added by the=
> doJoin()
>>and
>>methods like executeAllUpdatingDataObjects() (or manually added by you)
>>
>>
>>The first two parts (Static Join and Static Filter) are typically provided
>>by
>>the developer, and they tend to be fixed for all executions of this data
>>object
>>by all end users. In contrast, the three Dynamic Criteria types tend to
>>change
>>from one end user to another, and they may even change during the same end
>>user's session. For example, if the end user searches for all customers
>>living
>>in England, the doQBE() method would add a QBE Dynamic Criterion:
>>
>>
>>(Customers.Country =3D 'England')
>>
>>
>>
>>If the results of the query contain more than the requested number of rows
>>in
>>the output HTML, the end user may return after an unknown time period and
>>press
>>the <Next> button. Naturally, he/she would expect to see the next page of
>>all
>>customers that live in England. Between these two web events, another end
>>user
>>might "intrude" and search for customers whose first name begins with "Jo".
>>In
>>short, the dynamic parts of the the WHERE clause are automatically saved by
>>each
>>criteria data object as normal session objects. This is the mechanism
>>NetDynamics uses so that it does not get confused in such cases.
>>
>>There is a predefined hierarchy between the three parts of a dynamic
>>criteria:
>>
>>
>>=B7 QBE
>>
>>=B7 Drill Down
>>
>>=B7 Join
>>
>>
>>Consequently, high level Java CP methods that need to clear one level
>>automatically clear all levels below it.
>>
>>
>>=B7 doQBE() clears all dynamic criteria (QBE, Drill Down, and Join).
>>
>>=B7 doAction() may clear the Drill Down (and Join) criteria.
>>
>>=B7 doJoin() clears the Join part only.
>>
>>
>>In some cases you may add dynamic criteria yourself, check the criteria
>>automatically added by the system, clear some parts, and so on. The=
> database
>
>>package provides methods such as addDynamicCriterion(), getDynamicCriteria
>>and
>>clearDynamicCriteria() to perform such tasks.
>>
>>
>>Warning: Changes that you make to the dynamic criteria affect only the
>>current
>>end user (since criteria are automatically stored as user session objects).
>>Changes made to the other two parts of the WHERE clause (Static Join and
>>Static
>>Filter) affect all end users. They are member variables of data objects
>>shared
>>by all end users.
>>
>>-----Original Message-----
>>From: Mathew, Aby [mailto:[EMAIL PROTECTED]]
>>Sent: Friday, May 21, 1999 2:36 PM
>>To: 'Curt Springer';
>>[EMAIL PROTECTED]
>>Subject: Re: [ND] Why do I have to execute the dataobject before calling
>>i ts getValue()?
>>
>>
>>Curt,
>>
>>I too spent a lot of my ND life thinking Dynamic Criteria are as=
> trustworthy
>>as instance variables, until I was corrected recently.=20
>>
>>From what I learned, even though dataObject.addDynamicCriterion() sounds
>>like adding something to the DataObject instance, ND goes and keeps the
>>stuff in a userSessionObject, so it stays for the same user for later use.
>>This functionality seems to be crucial for the built-in handling of Next,
>>Prev etc.
>>
>>I had read a detailed note on this, but not able to locate it. It was=
> fairly
>>recently, otherwise I would doubt myself.
>>
>>Regards,
>>
>>Aby
>>
>>> -----Original Message-----
>>> From: Curt Springer [SMTP:[EMAIL PROTECTED]]
>>> Sent: Friday, May 21, 1999 2:38 PM
>>> To: [EMAIL PROTECTED]
>>> Subject: Re: [ND] Why do I have to execute the dataobject before
>>> calling its getValue()?
>>>=20
>>> see below
>>>=20
>>> At 11:02 AM 5/21/99 -0800, [EMAIL PROTECTED] wrote:
>>> >Hi,
>>> >
>>> >If some one could clarify the following that will be great-
>>> >
>>> >My Case:
>>> >I have a DO that is not bound to the page, I am calling it on=20
>>> >the onBeforeDisplay event of the page and adding dynamic=20
>>> >criterion to it to personalize the contents of the page=20
>>> >(actually a listbox on the page) for the user. Now I want to use
>>> >the same DO in onWebEvent of a button the page, regarding that I=20
>>> >have following questions-
>>> >1. Why do I have to call execute() method of the DO before=20
>>> >calling its getValue()?
>>>=20
>>> execute() causes the SQL 'select' statement to be sent to the dbms and
>>> results to be retrieved back. When the DO is bound to the page, the page
>>> calls execute() automatically. When the DO is not bound, you have to do
>>> it
>>> yourself.
>>>=20
>>> >2. Can I be sure that the DO's dynamic criteria is still the same
>>> >assuming multiple user sessions are active and provided I did=20
>>> >not change the criteria any where else in the code? My understanding is
>>> that- instances DOs are not shared between sessions.
>>>=20
>>> I must admit I took a long time to get this straight (pre-emptive
>>> statement).
>>>=20
>>> Dynamic criteria in a DO are like member variables in a page object. =
> They
>>> hold for the life of a web event, i.e., from a page load or beginning of
>>> button/href method, until a page is sent back to the browser (including
>>> the
>
>>> situation where you set criteria on a DO in a button event, then load
>>> another page and execute the DO in that page's onBeforeLoad or
>>> onBeforeDisplay event). And, at the outset of a web event, they must be
>>> assumed to reflect work done in a previous web event using the same
>>> object.
>>>=20
>>> At the beginning of a web event, the DO might have criteria set by=
> another
>>> page session. So before you add any dynamic criteria for the current=
> page
>>> session, you must execute clearDynamicCriteria on the DO. Then you can
>>> add
>>> your current criteria.
>>>=20
>>> Also, in case it was not clear above, in one web event, if you are in a
>>> button event of PageA, and you call CSpider.getDataObject("DO"),=20
>>> and then you load PageB, and in its onBeforeLoadEvent, you call the same
>>> CSpider.getDataObject("DO"), you will get the same object. =20
>>>=20
>>> -- Curt Springer, Team ND
>>>=20
>>>=20
>>> >
>>> >Thanks in advance to all the noble souls who are gonna reply...
>>> >
>>> >Vishal
>>>=
> >_________________________________________________________________________
>>> >
>>> >For help in using, subscribing, and unsubscribing to the discussion
>>> >forums, please go to:=
> http://www.netdynamics.com/support/visitdevfor.html
>>> >
>>> >For dire need help, email: [EMAIL PROTECTED]
>>> >=20
>>> _________________________________________________________________________
>>>=20
>>> For help in using, subscribing, and unsubscribing to the discussion
>>> forums, please go to: http://www.netdynamics.com/support/visitdevfor.html
>>>=20
>>> For dire need help, email: [EMAIL PROTECTED]
>>_________________________________________________________________________
>>
>>For help in using, subscribing, and unsubscribing to the discussion
>>forums, please go to: http://www.netdynamics.com/support/visitdevfor.html
>>
>>For dire need help, email: [EMAIL PROTECTED]
>>_________________________________________________________________________
>>
>>For help in using, subscribing, and unsubscribing to the discussion
>>forums, please go to: http://www.netdynamics.com/support/visitdevfor.html
>>
>>For dire need help, email: [EMAIL PROTECTED]
>>=20
_________________________________________________________________________
For help in using, subscribing, and unsubscribing to the discussion
forums, please go to: http://www.netdynamics.com/support/visitdevfor.html
For dire need help, email: [EMAIL PROTECTED]
