I'm considering creating an alternative to PFQueryTableViewController because I need some functionality that isn't offered.
I'm curious if the Load Next Page button on PFQueryTableViewController results in a server call?
...because in my implementation I'm going to run a query each time I need to load another page. I'm hoping that this won't be more expensive than PFQueryTableViewController.
When queryForTable is called it keeps a record of how many objects of that queried class are needed to display in the PFQTVC. The count is updated every time loadNextPage is called and loads the necessary data to fill the remaining objectsPerPage that you set for the PFQTVC. If there are more objects that could be loaded into the table, the PFQTVC can create a custom "Load More Cell" to load the next page, or remain content. So by having to update the table for next page and someone add a new post on a twitter like app for example, it would need to request that data because its new.
Related
i am using Spring/Hibernate/ZK. In one tab i get object from DB for editing by user, but second user can open the same tab and the same object for editing . I want to informed second user whit message like "This object is аlready open" and hide buttons for save.Тhus second user can see current data from DB to this object but can`t edint him.Is there a way to check session for this object or another way to do that.
The other answers mostly look at the database, but if all users use the same zk application to access the database, you could keep track of opened objects in the Composer or ViewModel (depending whether you use MVC or MVVM; I'll just call it controller).
Your controller would need a static list of objects that are currently modified. If a user requests to open an object that is not in the list, everything is fine and your controller enables the fields and save button. Otherwise, those are disabled and/or you display a message.
The tricky part is clearing objects from that list. If a user presses the save button, you just remove the object from the list. But what if the user doesn't and just closes the tab or their session just times out? In this case you need a callback, or a mechanism that regularly checks whether the screen is still open.
You could achieve this by adding a zk timer to the tab that pings every now and then and updates the timestamp in your static list (so make it a map). If a new user tries to edit the object, check how old the last timestamp is. If it is old enough (i.e. the previous user saved it or abandoned the screen), allow them to edit it.
Still, you have to think about what to do if a user just keeps the screen open. How long are they allowed to keep the lock on the object? This is an issue in Microsoft Office as well. If multiple users try to open an Excel file from a network location, the first one gets to lock and the others cannot save until that user saves.
You may have additional field which indicates that column is being edited. When first user starts work, the field would be updated. The second user would query object with 'on hold' status and your code would handle this.
Other way - use Hibernate #Version field in your entity. It holds object version which is incremented after every update operation. If second user would save object after first one already saved, it would throw OptimisticLockException which you could handle in your code. More about optimistic and pesimistic locking: Chapter 5. Locking. Related discussions: Hibernate Automatic Versioning and When to use #Version and #Audited in Hibernate?
The best solution is to use Optimistic Concurrency Control with Versioning and when Hibernate throws Concurrency Update issue due to same row is being updated in two transaction then use one of below strategy
First Wins Strategy
Last Wins Strategy
Merge Conflicting Update Strategy
First Wins Strategy is not good solution as it leads to lost update and user will get frustrated that all his work is lost.
By Last Wins Strategy one of user will get error message that you are working on Stale data and start your transaction again . By this way also user can get frustrated due to fact that now again he need to restart operation from beginning but his changes will not lost.
Instead go with Merge conflicting Update Strategy, when Hibernate throws Stale object exception reload screen with new data and user will see updated result and allow him to proceed with latest data. In this user changes will not loss and user will not get error message , just his screen reloads with fresh data and he can decide whether to proceed or not .
You can take example any e-commerce site and you will get one of result of either Last Wins Strategy or Merge Conflicting Update Strategy. Two user can start to by one item but one of user will get message in last screen that item is not stock.
In CRM Online on a customer form is there anyway that you can check if the Associated View for Assets is blank? And if its blank change a field value based on it.
Using JavaScript, 2 ways:
The associated grid is showing records related to your primary record. You can perform the same query the grid is doing using REST which will tell you if there are any records. You can then count the records, and change the field value as required. This approach is better if there are records in the database but which aren't shown in the view for some reason, e.g. view filters.
Access the Grid objects data using getRows(). As above you can then count the records, and change the field value as required. The downside of this is I believe those methods only give you access to the records shown on the form (and not any hidden by filters but still in the database) - but I don't think that that will be a problem here.
Worth bearing in mind that this approach only works client side, e.g. someone has to be actually looking at the form.
If you need to cover the a non-client side approach, e.g. workflows creating records, then you should probably look at plugin development so the changes can be performed server side.
As a side if you just want a simple count shown on form you then you should probably look at Calculated Fields and in particular Rollup fields. You might also be able to run further client side JavaScript from the count.
I'm writing a webmail-application by using smartgwt.
I'm trying to use auto-search on TextItem.
The TextItem is added a keyup-Handler and go to server side to do sql search every time when user
key-in a word. (I don't use js search because the speed of ie is very slow when doing filtering)
Further more, i use DSResponse.setData to create the listgrid records.
The problem is when setData is called, the grid always has a "loading data" message during the search.
How can i prevent this? Or just like PickListProperties, no "loading data" message, grid show the result without refresh.
Thanks!!
The message will appear whenever the grid calls the server to retrieve the data.
However you can, get the entire data on load, and whenever the the user keys in a word, just filter the grid by creating a new criteria like this :-
Criteria criteria=new Criteria();
criteria.addCriteria("name",textBox.getValue());
grid.filterData(criteria);
This way the loading message would not appear and also it would save you trips to server.
I have two drop down list on my registration page of sql type. they both fetch data from database. but my problem is that in second drop down list , i want specific data as per the option selected in dropdown list 1. how to do it?
thank you very much
There are two possibilities(well theoretically endless)..
1) You send the whole data on pageload and then filter it using javascript based on the first selection.
2) Use the ajax technique, where you send the ajax handler the selected value and then the handler queries the database and sends the relative data which you append on the second select in the runtime.
Note:- for larger tables the firstone is NOT Recommended.
I have a custom entity in Microsoft CRM (4.0). The user has to input records however usually they have a batch of 20+ records that are almost the same apart from 2 or 3 fields which need changing. I know I need to write some custom code to enable this functionally. However can anyone recommend any methods to do this.
Ideally there should be a button that will save and create a copy as a new entity.
My Current way of thinking is to pass all the details as part of the URL and use javascript to strip them out on the page load event. Any ideas welcome.
Thanks
Luke
I found the answer here:
http://mscrm4ever.blogspot.com/2008/06/cloning-entity-using-javascript.html
I've used it and it appears to work well.
Since there are numerous fields, but only certain fields values are different, then i am thinking to set the default value to all the fields, so that users just need to alter those values when needed.
In my approach, i will hook a javascript function on load of the form data entry screen and use XmlHttp approach/Ajax approach to hook to the custom web service to pull/retrieve the default values of each fields. Or you can set those values at the javascript function itself, but the drawback of this, it's difficult to customize later. So i will choose the approach to hook to the custom web service and retrieve those value from some application parameter entity.
Your idea of providing a "clone" button is also a great idea, which means that it will duplicate all the attributes of the previous record, into a new record, so that it will save time for data entry person to customize the different value
EDIT
Since you would enter records in batch mode, how about customizing .ASPX screen to enter records. By customizing through .ASPX screen, you can use a tab , so that users can browse through tabs, to customize the value/attribute of each record.
There will be a "save" button as well as "clone" button to clone some common attribute or value.
I would create a custom web service that would accept the entity type and the ID of the record I'm cloning. Your "Save and Clone" button would call the service, and the service would handle the details of retrieving the current record and deciding which fields to set on the new record. The service creates the record, and sends the Guid of the record back to your button, which then opens up the newly created record.
This way, you avoid the messiness of setting/getting values in JavaScript and tying which fields to set/retrieve directly to your OnLoads, as well as avoiding the possibility of query string that's too long.
The service could easily be sufficiently generalized so that all you'd have to do is add your button to any entity, and it would work, assuming you'd set up your service to handle that particular entity.
One possible downside is that since the clone record button would actually create the record, the user would be forced to delete the cloned record if they decided they didn't want to clone the record after all.