I work on an educational website in which we show dynamic filters. What does this mean? We now have several course categories that will increase in number in the following weeks.
Right now categories are a string field in each course. I'm planning to model this and create a Categories table. Having done this, it would be pretty easy to load the filters based on the categories we have on the database. However, I see the problem that each time the website is loaded, the query will be made.
I thought of caching these categories but I'm guessing is not the best solution.
Any idea on how can I avoid these queries each time but get this information from the database?
I'm working on a portal based on Orchard CMS. We're using Orchard to manage the "normal" content of the site, as well as to model what's essentially data for a small application embedded in it.
We figured that doing it that way is "recommended" for working in Orchard, and that it would save us duplicating a bunch of effort in features that Orchard already provides, mainly generating a good enough admin UI. This is also why we're using fields wherever possible.
However, for said application, the client wants to be able to display the data in the regular UI in a garden-variety datagrid that can be filtered, sorted, and paged.
I first tried to implement this by cobbling together a page with a bunch of form elements for the filtering, above a projection with filters bound to query string parameters. However, I ran into the following issues with this approach:
Filters for numeric fields crash when the value is missing - as would be pretty common to indicate that the given field shouldn't be considered when filtering. (This I could achieve by changing the implementation in the Orchard source, which would however make upgrading trickier later. I'd prefer to keep anything I haven't written untouched.)
It seems the sort order can only be defined in the administration UI, it doesn't seem to support tokens to allow for the field to sort by to be changed when querying.
So I decided to dump that approach and switched to trying to do this with just MVC controllers that access data using IContentQuery. However, there I found out that:
I have no clue how, if at all, it's possible to sort the query based on field values.
Or, for that matter, how / if I can filter.
I did take a look at the code of Orchard.Projections, however, how it handles sorting is pretty inscrutable to me, and there doesn't seem to be a straightforward way to change the sort order for just one query either.
So, is there any way to achieve what I need here with the rest of the setup (which isn't little) unchanged, or am I in a trap here, and I'll have to move every single property I wish to use for sorting / filtering into a content part and code the admin UI myself? (Or do something ludicrous, like create one query for every sortable property and direction.)
EDIT: Another thought I had was having my custom content part duplicate the fields that are displayed in the datagrids into Hibernate-backed properties accessible to query code, and whenever the content item is updated, copy values from these fields into the properties before saving. However, again, I'm not sure if this is feasible, and how I would be able to modify a content item just before it's saved on update.
Right so I have actually done a similar thing here to you. I ended up going down both approaches, creating some custom filters for projections so I could manage filters on the frontend. It turned out pretty cool but in the end projections lacked the raw querying power I needed (I needed to filter and sort based on joins to aggregated tables which I think I decided I didn't know how I could do that in projections, or if its nature of query building would allow it). I then decided to move all my data into a record so I could query and filter it. This felt like the right way to go about it, since if I was building a UI to filter records it made sense those records should be defined in code. However, I was sorting on users where each site had different registration data associated to users and (I think the following is a terrible affliction many Orchard devs suffer from) I wanted to build a reusable, modular system so I wouldn't have to change anything, ever!
Didn't really work out quite like I hoped, but to eventually answer the question in your title: yes, you can query fields. Orchard projections builds an index that it uses for querying fields. You can access these in HQL, get the ids of the content items, then call getmany to get them all. I did this several years ago, and I cant remember much but I do remember having a distinctly unenjoyable time with it haha. So after you have an nhibernate session you can write your hql
select distinct civr.Id
from Orchard.ContentManagement.Records.ContentItemVersionRecord civr
join civ.ContentItemRecord cir
join ci.FieldIndexPartRecord fipr
join fipr.StringFieldIndexRecord sfir
This just shows you how to join to the field indexes. There are a few, for each different data type. This is the string one I'm joining here. They are all basically the same, with a PropertyName and value field. Hql allows you to add conditions to your join so we can use that to join with the relevant field index records. If you have a part called Group attached directly to your content type then it would be like this:
join fipr.StringFieldIndexRecord sfir
with sfir.PropertyName = 'MyContentType.Group.'
where sfir.Value = 'HR'
If your field is attached to a part, replace MyContentType with the name of your part. Hql is pretty awesome, can learn more here: https://docs.jboss.org/hibernate/orm/3.3/reference/en/html/queryhql.html But I dunno, it gave me a headache haha. At least HQL has documentation though, unlike Orchard's query layer. Also can always fall back to pure SQL when HQL wont do what you want, there is an option to write SQL queries from the NHibernate session.
Your other option is to index your content types with lucene (easy if you are using fields) then filter and search by that. I quite liked using that, although sometimes indexes are corrupted, or need to be rebuilt etc. So I've found it dangerous to rely on it for something that populates pages regularly.
And pretty much whatever you do, one query to filter and sort, then another query to getmany on the contentmanager to get the content items is what you should accept is the way to go. Good luck!
You can use indexing and the Orchard Search API for this. Sebastien demoed something similar to what you're trying to achieve at Orchard Harvest recently: https://www.youtube.com/watch?v=7v5qSR4g7E0
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 created an extension for joomla using:
$id=$database->insertid();
I just covered that if two users are logged on to the site will fit together perform two records in the database and then this statement will return in both cases the same value.
in php you can solve this problem with the transactions.
In joomla how do I solve this problem?
If you have a table you are working with that extends JTable then make sure that you included the check out functionality that is optionally a part of that. THis must means adding a couple of fields like what is in the content table. This will prevent two people from editing the same row at the same time which creates a race condition in which one of the other will lose their data.
Please note that both php and joomla functions to return the last insert id rely on the mysql implementation, and mysql returns the last id inserted on the currently open connection so concurrency is not an issue
#iacoposk8 Your are right it might possible that in very rear case. Such time try to add current logged in user id in your sql query or any where so that it doesn't make any confict. I hope you get it what i want to say. Thanks
I have got a situation where I have list of records say 10,000, I am using datatable and I am using paging,(10 records per display). I wanted to put put that list in the session as:
facesContext........put("mylist", mylist);
And in the getters of the mylist, I have
public List<MyClass> getMyList() {
if(mylist== null){
mylist= (List<MyClass>) FacesContext......getSessionMap().get("mylist");
}
return mylist;
}
Now the problem is whene ever i click on paging button to go to second page, only the first records are displayed,
I know i am missing some thing, and I have few questions:
Is the way of putting the list in session correct.
Is this the way I should be calling the list in my case.
Thnaks in advance...
Something entirely different: I strongly recommend to not put those 10.000 records in the session scope. That is plain inefficient. If 100 users are visiting your datatable, those records would be duplicated in memory for every user. This makes no sense. Just leave them in the database and write SQL queries accordingly that it returns exactly the rows you want to display per request. That's the job the DB is designed for. If the datamodel is well designed (indexes on columns involved in WHERE and if necessary ORDER BY clauses), then it's certainly faster than hauling the entire table in Java's memory for each visitor.
You can find more insights and code examples in this article.