Some background just in case there is a better way to do this other than the way I am trying:
I am requesting data of a rest API. When the data is received I want to check if a model containing this data already exists. The rest API does not give an ID for data entry so I cannot use this to see if a model instance already exists.
I have created an equal magic method for the model that checks several of the fields to see if they are equal and returning the appropriate boolean. This works fine when checking for example if instance == other_instance.
The issue arises when I try to filter or get to check the DB.
breach = Breach.objects.get(self=breach1)
I could check by specifying the fields each time but this would lead to some duplicated code over time and make the code base maintainable.
I am still newish to using Django so apologies if Django has a simple way of doing this.
I ran across a problem for which I found no documented solution, but inadvertently found the solution myself. So I wanted to document this here for others who may encounter the same problem.
I was using a CAML query within SPServices to retrieve list items, then referencing "ows_{fieldname}" as usual to retrieve the field value for each list item. The field value was reported as "undefined" for all items. I quintuple-checked that I was specifying the proper name of the field and that my query was properly constructed.
I eventually discovered that the fields I was trying to reference were not displayed in the default view of the list. As soon as I changed the list properties to include the fields in the default view, the proper field values were returned within my javascript.
I don't know how much of Sharepoint's underpinnings work, but I was very surprised at my finding because it implies that the SPServices GetListItems method gets its data from the list's default view, not the actual underlying list. I realize I could be wrong in this interpretation, but I imagine others could run into this same problem.
The default, although unreliable, way GetListItems works is that it's suppose to returns all fields displayed on the default list view if you don't specify ViewFields on input. This is unreliable. Although you got it working - now - someone could come along later and change the default view thus breaking your sweet customization. Bummer. :)
I suggest always listing the ViewFields you are interested in on the GetListItems method. This ensures that your will get them if they are set. That's right. You could still get rows with an undefined field. This happens mostly on fields of type Lookup that are not set on a row.
Hope this helps you understand what is going on. Over the years I have created my own wrappers around SPServices to ensure I get back a reference to all fields requested, even if they are not in the response by Sharepoint.
When using SPServices' GetListItems method, be sure that any fields that you reference from the list are included in the list's default view, otherwise an undefined value will be returned.
I'm been searching around, and I dont understand why it is, that if I create a query for the projection and I say I want to filter a field of the returned Content Type by a Field of the current user, that no rows are returned.
If I replace the token with a hard coded value, it does work. I'm just missing some important understanding about why the token has no value.
This is not how it works. You may use tokens in projections as long as they are not expected to vary per record. Tokens can be used if they are external data (querystring parameters, etc.) To make your scenario work, you'll have to build your own filter.
I have three document types MainCategory, Category, SubCategory... each have a parentid which relates to the id of their parent document.
So I want to set up a view so that I can get a list of SubCategories which sit under the MainCategory (preferably just using a map function)... I haven't found a way to arrange the view so this is possible.
I currently have set up a view which gets the following output -
{"total_rows":16,"offset":0,"rows":[
{"id":"11098","key":["22056",0,"11098"],"value":"MainCat...."},
{"id":"11098","key":["22056",1,"11098"],"value":"Cat...."},
{"id":"33610","key":["22056",2,"null"],"value":"SubCat...."},
{"id":"33989","key":["22056",2,"null"],"value":"SubCat...."},
{"id":"11810","key":["22245",0,"11810"],"value":"MainCat...."},
{"id":"11810","key":["22245",1,"11810"],"value":"Cat...."},
{"id":"33106","key":["22245",2,"null"],"value":"SubCat...."},
{"id":"33321","key":["22245",2,"null"],"value":"SubCat...."},
{"id":"11098","key":["22479",0,"11098"],"value":"MainCat...."},
{"id":"11098","key":["22479",1,"11098"],"value":"Cat...."},
{"id":"11810","key":["22945",0,"11810"],"value":"MainCat...."},
{"id":"11810","key":["22945",1,"11810"],"value":"Cat...."},
{"id":"33123","key":["22945",2,"null"],"value":"SubCat...."},
{"id":"33453","key":["22945",2,"null"],"value":"SubCat...."},
{"id":"33667","key":["22945",2,"null"],"value":"SubCat...."},
{"id":"33987","key":["22945",2,"null"],"value":"SubCat...."}
]}
Which QueryString parameters would I use to get say the rows which have a key that starts with ["22945".... When all I have (at query time) is the id "11810" (at query time I don't have knowledge of the id "22945").
If any of that makes sense.
Thanks
The way you store your categories seems to be suboptimal for the query you try to perform on it.
MongoDB.org has a page on various strategies to implement tree-structures (they should apply to Couch and other doc dbs as well) - you should consider Array of Ancestors, where you always store the full path to your node. This makes updating/moving categories more difficult, but querying is easy and fast.
I have core data app with an entity OBSERVATION that has as one of its attributes DEALNAME.
I want to reference through Interface Builder or by making custom modifications to an NSArrayController a list of unique sorted dealnames so that I can use them in a pop-up.
I have attempted to use #distinctUnionOfSets (and #distinctUnionOfArrays) but am unable to locate the proper key sequence.
I can sort the ArrayController by providing a sort descriptor, but do not know how to eliminate duplicates.
Are the #distinct... keys the right methodology? It would seem to provide the easiest way to optimize the use of IB.
Is there a predicate form for removing duplicates?
Or do I need to use my custom controller to extract an NSSet of the specific dealnames, put them back in an array and sort it and reference the custom array from IB?
Any help would be appreciated. I am astounded that other have not tried to create a sorted-unique pop-up in tableviews.
You need to take a look at -[NSFetchRequest returnsDistinctResults]. That is the level you need to be handling the uniquing of data.
Although I do not have a definitive answer for you, I think there are two ways you can go about it.
The way you already started. You need to bind the contents array of the PopUp button, not just against the arrayController.arrangedObjects, but continue on the path and somehow filter only objects with distinct "DealName"s. This means - the arrayController presents ALL the entities (and may sort them for you) but the PopUp button will have its contents filter via some sophisticated binding to the array controller.
Make your filtering at the ArrayController level (as suggested in another answer here). Here it depends how you set up the array controller. If It is set up to use an "Entity" (vs. "Class") which means the array controller will fetch CoreData entities directly - you can modify its "Fetch" to only bring a subset of the "OBSERVATION" entities with distinct values of "DEALNAME". I don't know how to control WHICH entities are filtered out in this case. Otherwise, you can setup the arrayController to work with "Class" objects, and then you can fetch the entities yourself (in code) and populate the arrayController programmatically, with just the entities you like.
In the second option, the Popup button should be bound normally to the arrayController's arrangedObjects.