I like how cleanly an object is stored in ravenDB, but have a practical question for which I'm not sure of the best answer.
Lets say i have a quote request:
QuoteRequest.cs
int Id;
dateTime DateCreated;
List<Quotes> Quotes;
Quote.cs
int ProviderId;
int Price;
int ServiceDays;
int ServiceTypeId;
when someone hits a page, i spit out a list of quotes from which they can choose. These quotes are only related to an instance of the quote request.
My question is, since a child object, such as a quote in the list, doesnt have an Id generated by the database, how do I generate a querystring to let the next page know which quote the user wants to buy?
There could be multiple quotes by one providerId.
My thoughts were either add a QuoteId and increment it based on this.Quotes.Count, but that seems a little hacky, or generate a random number, also a little hacky.
How do people generally handle something like this?
Do you really need to associate the purchase (what the user chose to buy) with the original quote? I'm guessing that you take the quote and then convert it to a purchase.
If that is so, then don't worry about an id at all. Just pass along the constituent values to the next step. In other words, treat quote like a Value in the DDD sense.
However, if you do need to store an association to the purchase... well, then it depends on what you really need to track. For example, you could just update the QuoteRequest, marking the selected quote. (Add an IsSelected or something similar to the quote class Quote.) Then the purchase could be linked back to the quote request, and you could identify the quote by way of the flags.
Again, all this depends on the context (and I'm just making guesses about that).
Since no one has answered this yet I'll just say how I would do it;
Why add a Id at all? just use the index of the List? It the request is "?quote=0" they get the quote at position 0?
Not really sure If I'm not getting something here though...
One option is to have the parent object store the last used id. When adding a new child object you increment the id-counter and add that to the child. When the object is saved the id-counter is automatically incremented.
Lets say you have blog post with comments:
public class Post
{
public int NextCommentId;
public List<Comment> Comments;
...
}
...
var comment = new Comment { Id = post.NextCommentId++ };
post.Comments.Add(comment);
session.SaveChanges();
The code above might not be 100% correct, but should give you an idea of how to do it at least!
Related
I'm trying to learn Grails but am still pretty much on beginner level.
I made a tiny application, where you can basically add events, and people can write reviews about them and rate them.
So I have an eventController and reviewController. The rating is just an Integer in a review. But now I want to show an overall rating for an event. So the events rating should be the average value of the corresponding ratings value.
This is my event domain code where the rating is initially set, I left out the constraints and toString:
class Event {
Double dRating = 2
static hasMany = [ratings:Rating]
}
The controller is simply:
class EventController {
def scaffold = Event
}
The rating domain file:
class Rating {
String comment
java.util.Date date = new java.util.Date()
Integer rating
Event event
}
and the Rating Controller is:
class RatingController {
def scaffold = Rating
}
Hope I didn't make mistakes, I had to translate variable names so they're understandable.
I'm guessing that where dRating is set, I could somehow add some calculation, but I don't even know how to access the values of the rating, and everything I try ends in lots of errors and having to restart the app again and again. I tried adding calculations in the controller, but there I don't know how to get the value into the database. So where do I actually put the logic, and how do I access the values?
If any other file is important, please tell me.
Hoping to get some hints on how to start doing this, I didn't think it would be this hard.
At first I would recommend start reading grails doc. Later from your question it is not much clear what you are asking a there could be several places or possibilities of setting up the value in domain field and persist it to database. I'm telling all of these which are known to me:
If it is generalised calculation that needs to be applied to your dRating field, then create a setter with standard bean naming convention and do this there. For example, you want to find percentage from say 1000 and then add it to dRating
class Event {
static hasMany = [ratings:Rating]
Double dRating
void setDRating(Double value){
this.dRating = value * 100/1000 // alternatively value /10
}
}
Do it in commandObject: If you don't want to put certain calculations and validation in domain then put these in command objects. See this. You can at any point of time assign values from command object to domain object by .properties binding mechanism. For example,
yourDomainObject.properties = yourcommandObjectObject.properties
Remember properties having same name would be binded.
Do it in service: You can do your calculations in service method, inject that service into your controller and call that method to perform calculations and even to persist to db as well. Remember services are by default transactional.
Hope it helps!
I just wasted half a day trying to figure this out, reading about some workarounds, and thinking "it can't be that bad - there must be a straightforward to do edit a collection in Grails, whethere using scaffolded views or my own."
Let's say I have this domain object:
class TreeGroup {
String name
List<Tree> trees
static hasMany = ['trees': MyTree]
}
Just to explain the choice of data structure - I need my records to be unique, but in the order I set. That's why I chose List, AFAIK one cannot rely on order in a Set. So there are 2 pieces to this question - 1) how to remove from any Collection, for example a Set, 2) is List the best replacement for Set in this context (preserving order).
I want to be able to create a group record with no trees in it and make 4 updates:
edit/save
edit the group record to reference 2 trees A and B
add another tree C
remove A
remove B and C
And obviously, I want the desired state after every step. Currently though, I can only add records, and if I even edit/save to list, the list elements are added to it again.
I am using the multiple select tag for this. It looks like this:
<g:select name="trees" from="${allTrees}" optionKey="id"
multiple="true" class="many-to-many"
value="${trees ? trees*.id : treeGroupInstance?.trees*.id}" />
and that's fine, in the sense that it generates an HTTP header with these variables on update:
_method:PUT
version:19
name:d5
trees:1
_action_update:Update
But the data binder only adds new elements, it never lets you edit a list.
What is the cleanest way to do it ? Is it me, not reading something obvious, or is this a design flaw of grails data binding (and of so, when/how will it be fixed) ?
Is there a way perhaps via a hidden HTTP parameter to clear the list before (re)adding elements ?
Thanks
I ended up doing this:
private repopulate(def domainObject, String propertyName, Class domainKlaz) {
if (params[propertyName] != null) {
domainObject[propertyName].clear()
domainObject[propertyName].addAll(
params[propertyName].collect { domainKlaz.get(it) }
)
}
}
and I am calling it in update controller method before save(), for every collection. OMG how ugly.
I have an array of bytes in my model
public byte[] created_dt { get; set; }
It represents a timestamp value in the database.
In my view , I am referring it as #model.created_dt
but it is coming as system.byte[]
How to resolve this?
Try as this is just an example to achieve the functionality
#foreach(var a in model.created_dt){
<label>#a</label>
}
Judging by the behavior, this looks like ASP.NET and you are simply seeing the output of an implicit call to ToString() on the array (the default way of displaying anything that does not have a template defined). You will have to do something with the raw byte data and present it to the user.
Since you refer to "timestamp" and the property name might suggest a record creation time, you may want to write a helper method to translate this raw data to a DateTime which you could then format accordingly.
However, one of the following is most likely true:
It strikes me as odd that you are using raw binary to store what should otherwise be a datetime2 column. (Or it is a datetime in your database but you're doing something unorthodox to retrieve the value.)
Your property/column name of "created_dt" is a misnomer and it is really a timestamp (i.e. rowversion) column. In which case I don't think this is something a user would know what to do with, and it probably doesn't belong on the UI.
Since Intuit has broken the QBFC reference today, I have to ask a question that I could normally look up. (I do not know who to complain to).
I normally query by list_id like so:
ICustomerQuery CustomerQueryRq = requestMsgSet.AppendCustomerQueryRq();
CustomerQueryRq.ORCustomerListQuery.ListIDList.Add(qb_list_id);
Is there a way to query by AccountNumber?
Thanks!
No, QuickBooks does not support querying by the AccountNumber field.
This is old, but maybe worth adding.
Create a temp "cached" object, containing all the properties you want to search for. Them when launching, and whenever customer changes are made, cache a list of custom QBcustomersForSearch objects with only the properties that you would want to use for the search.
class qbCustomerForSearch
property email as string
property accountnumber as string
property whatever as string
property QBListId as string
end class
Cache / create a list of these objects when and as needed, and search your list. Once located in your list, use the listID to identify the QB customer.
Cheers
I am looking for a simple way to hydrate a related object. A Note belongs to a Document and only owners of a Document can add Notes so when a user tries to edit a Note, I need to hydrate the related Document in order to find out if the user has access to it. In my Service layer I have the following:
public void editNote(Note note)
{
// Get the associated Document object (required for validation) and validate.
int docID = noteRepository.Find(note.NoteID).DocumentID;
note.Document = documentRepository.Find(docID);
IDictionary<string, string> errors = note.validate();
if (errors.Count > 0)
{
throw new ValidationException(errors);
}
// Update Repository and save.
noteRepository.InsertOrUpdate(note);
noteRepository.Save();
}
Trouble is, noteRepository.InsertOrUpdate(note) throws an exception with "An object with the same key already exists in the ObjectStateManager." when the repository sets EntityState.Modified. So a number of questions arise:
Am I approaching this correctly and if so, how do I get around the exception?
Currently, the controller edit action takes in a NoteCreateEditViewModel. Now this does have a DocumentID field as this is required when creating a new Note as we need to know which Document to attach it to. But for edit, I cannot use it as a malicious user could provide a DocumentID to which they do have access and thus edit a Note they don't own. So should there be seperate viewmodels for create and edit or can I just exclude the DocumentID somehow on edit? Or is there a better way to go about viewmodels such that an ID is not required?
Is there a better way to approach this? I have read that I should just have a Document repository as an aggregate and lose the Note repository but am not sure if/how this helps.
I asked a similar question related to this but it wasn't very clear so hoping this version will allow someone to understand and thus point me in the right direction.
EDIT
Based on the information provided by Ladislav Mrnka and the answer detailed here: An object with the same key already exists in the ObjectStateManager. The ObjectStateManager cannot track multiple objects with the same key, it seems that my repository method need to be like the following:
public void InsertOrUpdate(Note note)
{
if (note.NoteID == default(int)) {
// New entity
context.Notes.Add(note);
} else {
// Existing entity
//context.Entry(note).State = EntityState.Modified;
context.Entry(oldNote).CurrentValues.SetValues(note);
}
}
But how do I get the oldNote from the context? I could call context.Entry(Find(note.NoteID)).CurrentValues.SetValues(note) but am I introducing potential problems here?
Am I approaching this correctly and if so, how do I get around the exception?
I guess this part of your code loads the whole Node from the database to find DocumentID:
int docID = noteRepository.Find(note.NoteID).DocumentID;
In such case your InsertOrUpdate cannot take your node and attach it to context with Modified state because you already have note with the same key in the context. Common solution is to use this:
objectContext.NoteSet.ApplyCurrentValues(note);
objectContext.SaveChanges();
But for edit, I cannot use it as a malicious user could provide a DocumentID to which they do have access and thus edit a Note they don't own.
In such case you must add some security. You can add any data into hidden fields in your page but those data which mustn't be changed by the client must contain some additional security. For example second hidden field with either signature computed on server or hash of salted value computed on server. When the data return in the next request to the server, it must recompute and compare signature / hash with same salt and validate that the passed value and computed value are same. Sure the client mustn't know the secret you are using to compute signature or salt used in hash.
I have read that I should just have a Document repository as an aggregate and lose the Note repository but am not sure if/how this helps.
This is cleaner way to use repositories but it will not help you with your particular error because you will still need Note and DocumentId.