Well, by means of historical session, we can query an object at a specific time. But what I need is to query all the versions of that object..
The documentation points out that we can not do this.. But is there anyone that customize eclipselink for this behaviour?..
edit : well, this question has been asked at eclipselink forums. It seems that nobody interested in this question.
EDIT :
I have requested an enhancement request. If you want this enhancement, please vote.. Here is the link : https://bugs.eclipse.org/bugs/show_bug.cgi?id=333725
Here is the answer from eclipselink forum ..
There does not seem to be an easy way
to do this. Please log an enhancement
request and vote for it.
You can use a native SQL query for
this. You will need to set
"eclipselink.maintain-cache"="true" on
the query.
You could also map a separate class to
the historical table, and include the
start and end date in the object, and
the startDate as part of the Id. This
is really what you would want to do,
as querying the original class will
not give you access to the start and
end dates. You could use a
MappedSuperclass and have the current
and historical class subclass it and
use the different tables.
Related
I've been researching this for a while and still couldn't find a satisfactory answer for my problem.
I have an entity on my postgres DB (product) that has a ManyToOne relationship with another entity (Dun).
Each product may have N duns.
On my PUT endpoint, the desired behavior would be:
Every time I update a product, it replaces all the duns with the ones provided on the endpoint.
Is there any way to handle it automatically by Hibernate/JPA?
In order to make it easier to test and explain the issue, I've uploaded a project on Github on the following link https://github.com/brunapereira/jpaexample
If there's no way to handle it automatically by JPA, what's the best way to solve it with code?
Thanks in advance,
First, you need to remove Duns by product id, then get the product by id, add the new duns then save back.
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
I need to load model validations from a table and validate my model. e.g. I have a database table called validations, which has rows like :
validation_action validation_condition
---------------- --------------------
validates_presence_of if answer_name is name
validates_format_of if answer_type is date
In my model I want:
class Model < ActiveRecord::Base
load validation_actions , lambda {if validation_condition is true}
Ok more detail:
I am creating an app for taking surveys. I am storing questions in a table and answers in another table. I need to store the validation for each answer in the question table and validate each answer before I accept it. I can query validation for each question and run it in controller but I want to do it in model instead as it is much cleaner.
so two models :
Questions -> table questions sas code and details about questions
Answers -> table answers stores answers with a foreign key to Questions.
I want to validate the input in Answers model depending upon conditions defined in questions database table.
Please let me know if more detail is needed?
If I understand correctly, you have Questions which have many associated Answers, and also have associated ValidationActions. When an Answer is being saved, you want to run validations against it based on evaluating code stored in the ValidationActions belonging to it's associated Question object.
This seems like a bad idea. Not so much that validations are conditional on the state of an associated object (the Question), which is the sort of thing that does happen, but that you're doing what amounts to executing code from the contents of the database. This is one of those things that makes web developers twitchy - the security issue is the most obvious reason (that if someone can edit your database's fields, they can cause arbitrary code to run on your system), but it's definitely a questionable practice even outside that (I'm having trouble articulating the reason more convincingly than 'code is code and data is data and never the twain shall meet', but there it is).
All that said, it should be possible to write a custom validator as explained here to handle this. It will doubtless be inefficient, might well be prone to breakage, and is probably a security hole unless it's written very carefully. But it's possible.
I am struggling a bit on what probably is a simple matter or something I misunderstand... But anyway, using Linq entity code first, I am trying to keep some of my tables to be inaccessible from the client, without success.
Using Breeze, I have made a datacontext that holds only the dbsets I want exposed, fine.
But when I write a query using .expand(). For example, let's say I have a posts table which I want to expose, and an Owner table that I want to hide.
Using a query like:
var query = EntityQuery
.from('Posts')
.expand('Owner');
I can still see all the columns from Owner.
So the question is: in Linq, how am I supposed to secure/protect/hide the tables, and/or specific columns, that I want to hide?
After some digging, all I have found is the [JsonIgnore] attribute, which seems insufficient to me.
What is the best way to do this? I feel I am missing something probably huge here, but it's the end of the day around here...
Thanks
If you are using the Breeze's WebApi implementation then Breeze also supports ODataQueryOptions ( see here and here ).
This allows you to mark up your controller methods so as to limit how the query is interpreted. For example, to only allow filtering on your 'Posts' query and therefore exclude the ability to "expand" or "select" 'Owners' from any 'Posts' request you could do the following.
[Queryable(AllowedQueryOptions=AllowedQueryOptions.Filter| AllowedQueryOptions.Top | AllowQueryOptions.Skip)]
public IQueryable<Posts> Posts() {
....
}
Ok apparently my question was already addressed here:
Risks of using OData and IQueryable
I just found it.
Disclaimer: I'm not a programmer, so this question is non-technical and probably very basic. I am just hoping to be pointed in the right direction...
I want to automate the routine process of compiling custom lists of medical questions by matching a question's attribute tags to the attributes of the patient and ailment. I've built an Access DB which generates lists when queried based on these tags. But I also need to set rules to determine the order the questions are returned in. Otherwise the questions are "out of order" and don't make sense.
Is there a better (and ideally browser based) software or service I could use to achieve such search/reporting functionality? Or does I need to find someone who can add this functionality to my access DB?
Thanks in advance!
It kind of depends on how you generate "lists when queried based on these tags".
If you're using sql to select from the database, then it may just be a matter of adding an "order by" to the end of your query:
eg:
Select question_no, question from some_table where patient = 'Freddy'
and tag = 'sick' order by question_no
Generally speaking, however you are retrieving these questions; the easiest way of ordering them is by one or more columns in the table you're storing the questions (or a related table)