I have two types of entities: Subjects and Correspondents. They're both related to each other via a to-many relationship. I want to have a single fetchRequest that I can pass to a NSFetchedResultsController which will have it return:
All of the subjects which have more than one correspondent.
All of the correspondents which have subjects that only they are apart of.
After trying a variety of things, I decided that it's not possible to make a single fetch that returns both Subjects and Correspondents, so I turned to StackOverflow and found someone else suggesting that you have a single entity which does nothing more than have relationships with the two entities you'd like to return.
So I created a third type of entity, which I called Folders, which each have an optional to-one relationship with a Subject and a Correspondent. It also has two attributes, hasCorrespondent and hasSubject, which are booleans keeping track of whether Subject or Correspondent are set.
So I wrote this predicate which returns the Folder entities:
(hasCorrespondent == 1 AND ANY correspondent.subjects.correspondents.#count == 1)
OR
(hasSubject == 1 AND subject.correspondents.#count >= 1)
The issue with this is I'm getting an error:
Terminating app due to uncaught exception 'NSInvalidArgumentException',
reason: 'Unsupported function expression count:(correspondent.subjects.correspondents)
So, any suggestions as to what I'm doing incorrectly? How can I accomplish what I'd like? Are there any additional details I should share?
UPDATE
With Martin's suggestion, I changed the offending portion to this:
SUBQUERY(correspondent.subjects, $s, $s.correspondents.#count == 1).#count > 0
But that generated a new error:
Keypath containing KVC aggregate where there shouldn't be one;
failed to handle $s.correspondents.#count
After googling around, I found suggestions to add a check that the collection being enumerated over had at least one object, but modifying the offending line to this didn't change my error messages (so as far as I can tell it did nothing):
correspondent.subjects.#count > 0 AND
SUBQUERY(correspondent.subjects, $s, $s.correspondents.#count == 1).#count > 0
I had a similar problem. I created an additional field countSubentity. And when add/remove subentity change this field. And predicate looks:
[NSPredicate predicateWithFormat:#"SUBQUERY(subcategories, $s,
$s.countSubentity > 0).#count > 0"];
This work around has been less than ideal, but it seems to get the job done:
1 - I added an attribute to subject called count.
2 - I set (part of) my expression to
ANY correspondent.subjects.count == 1
Note that no SUBQUERY() was necessary for this workaround.
3 - Everytime I modify a subject's correspondents set, I run
subject.count = #(subject.correspondents.count);
I'm still hoping for a better solution and will be happy to mark any (working) better solution as correct.
Related
It seems to be a simple question but I have a hard time to find an answer to it. I already have a project with several parameters (project and database parameters). I would like to obtain the LCA results for several scenarios with my parameters having different values each time. I was thinking of the following simple procedure:
change the parameters' value,
update the exchanges in my project,
calculate the LCA results.
I know that the answer should be in the documentation somewhere, but I have a hard time to understand how I should apply it to my ProjectParameters, DatabaseParameters and ActivityParameters.
Thanks in advance!
EDIT: Thanks to #Nabla, I was able to come up with this:
For ProjectParameter
for pjparam in ProjectParameter.select():
if pjparam.name=='my_param_name':
break
pjparam.amount = 3
pjparam.save()
bw.parameters.recalculate()
For DatabaseParameter
for dbparam in DatabaseParameter.select():
if dbparam.name=='my_param_name':
break
dbparam.amount = 3
dbparam.save()
bw.parameters.recalculate()
For ActivityParameter
for param in ActivityParameter.select():
if param.name=='my_param_name':
break
param.amount = 3
param.save()
param.recalculate_exchanges(param.group)
You could import DatabaseParameter and ActivityParameter iterate until you find the parameter you want to change, update the value, save it and recalculate the exchanges. I think you need to do it in tiers. First you update the project parameters (if any) then the database parameters that may depend on project parameters and then the activity parameters that depend on them.
A simplified case without project parameters:
from bw2data.parameters import ActivityParameter,DatabaseParameter
# find the database parameter to be updated
for dbparam in DatabaseParameter.select():
if (dbparam.database == uncertain_db.name) and (dbparam.name=='foo'):
break
dbparam.amount = 3
dbparam.save()
#there is also this method if foruma depend on something else
#dbparam.recalculate(uncertain_db.name)
# here updating the exchanges of a particular activity (act)
for param in ActivityParameter.select():
if param.group == ":".join(act.key):
param.recalculate_exchanges(param.group)
you may want to update all the activities in the project instead of a single one like in the example. you just need to change the condition when looping through the activity parameters.
In case we had the model:
class Publication(models.Model):
title = models.CharField(max_length=30)
class Article(models.Model):
publications = models.ManyToManyField(Publication)
According to: https://docs.djangoproject.com/en/4.0/topics/db/examples/many_to_many/, to create an object we must have both objects saved before we can create the relation:
p1 = Publication(title='The Python Journal')
p1.save()
a1 = Article(headline='Django lets you build web apps easily')
a1.save()
a1.publications.add(p1)
Now, if we called delete in either of those objects the object would be removed from the DB along with the relation between both objects. Up until this point I understand.
But is there any way of doing that, if an Article is removed, then, all the Publications that are not related to any Article will be deleted from the DB too? Or the only way to achieve that is to query first all the Articles and then iterate through them like:
to_delete = []
qset = a1.publications.all()
for publication in qset:
if publication.article_set.count() == 1:
to_delete(publication.id)
a1.delete()
Publications.filter(id__in=to_delete).delete()
But this has lots of problems, specially a concurrency one, since it might be that a publication gets used by another article between the call to .count() and publication.delete().
Is there any way of doing this automatically, like doing a "conditional" on_delete=models.CASCADE when creating the model or something?
Thanks!
I tried with #Ersain answer:
a1.publications.annotate(article_count=Count('article_set')).filter(article_count=1).delete()
Couldn't make it work. First of all, I couldn't find the article_set variable in the relationship.
django.core.exceptions.FieldError: Cannot resolve keyword 'article_set' into field. Choices are: article, id, title
And then, running the count filter on the QuerySet after filtering by article returned ALL the tags from the article, instead of just the ones with article_count=1. So finally this is the code that I managed to make it work with:
Publication.objects.annotate(article_count=Count('article')).filter(article_count=1).filter(article=a1).delete()
Definetly I'm not an expert, not sure if this is the best approach nor if it is really time expensive, so I'm open to suggestions. But as of now it's the only solution I found to perform this operation atomically.
You can remove the related objects using this query:
a1.publications.annotate(article_count=Count('article_set')).filter(article_count=1).delete()
annotate creates a temporary field for the queryset (alias field) which aggregates a number of related Article objects for each instance in the queryset of Publication objects, using Count function. Count is a built-in aggregation function in any SQL, which returns the number of rows from a query (a number of related instances in this case). Then, we filter out those results where article_count equals 1 and remove them.
I have created a non-persistent attribute in my WoActivity table named VDS_COMPLETE. it is a bool that get changed by a checkbox in one of my application.
I am trying to make a automatisation script in Python to change the status of every task a work order that have been check when I save the WorkOrder.
I don't know why it isn't working but I'm pretty sure I'm close to the answer...
Do you have an idea why it isn't working? I know that I have code in comments, I have done a few experimentations...
from psdi.mbo import MboConstants
from psdi.server import MXServer
mxServer = MXServer.getMXServer()
userInfo = mxServer.getUserInfo(user)
mboSet = mxServer.getMboSet("WORKORDER")
#where1 = "wonum = :wonum"
#mboSet .setWhere(where1)
#mboSet.reset()
workorderSet = mboSet.getMbo(0).getMboSet("WOACTIVITY", "STATUS NOT IN ('FERME' , 'ANNULE' , 'COMPLETE' , 'ATTDOC')")
#where2 = "STATUS NOT IN ('FERME' , 'ANNULE' , 'COMPLETE' , 'ATTDOC')"
#workorderSet.setWhere(where2)
if workorderSet.count() > 0:
for x in range(0,workorderSet.count()):
if workorderSet.getString("VDS_COMPLETE") == 1:
workorder = workorderSet.getMbo(x)
workorder.changeStatus("COMPLETE",MXServer.getMXServer().getDate(), u"Script d'automatisation", MboConstants.NOACCESSCHECK)
workorderSet.save()
workorderSet.close()
It looks like your two biggest mistakes here are 1. trying to get your boolean field (VDS_COMPLETE) off the set (meaning off of the collection of records, like the whole table) instead of off of the MBO (meaning an actual record, one entry in the table) and 2. getting your set of data fresh from the database (via that MXServer call) which means using the previously saved data instead of getting your data set from the screen where the pending changes have actually been made (and remember that non-persistent fields do not get saved to the database).
There are some other problems with this script too, like your use of "count()" in your for loop (or even more than once at all) which is an expensive operation, and the way you are currently (though this may be a result of your debugging) not filtering the work order set before grabbing the first work order (meaning you get a random work order from the table) and then doing a dynamic relationship off of that record (instead of using a normal relationship or skipping the relationship altogether and using just a "where" clause), even though that relationship likely already exists.
Here is a Stack Overflow describing in more detail about relationships and "where" clauses in Maximo: Describe relationship in maximo 7.5
This question also has some more information about getting data from the screen versus new from the database: Adding a new row to another table using java in Maximo
I am trying to validate one block of json data that I receive from server
json consists of information about bunch of orders. An each order includes cost of each part, taxes and total. And it is kind of strict requirement each order contains exactly 4 parts. And each order has three kind of taxes and a total.
I have a step which looks like this
And "standardorder" includes parts "1..4", taxes "1..3" and total
and step implementation is like following. Here #jsonhelper.json is shared state (json for one order) passed from previous step.
And /^"([^"]*)" includes parts "([^"]*)", taxes "([^"]*)" and total$/ do |arg1, arg2, arg3|
json = #jsonhelper.json
validkeys = ["total"]
parts = arg2.split('..').map{|d| Integer(d)}
(parts[0]..parts[1]).each do |i|
validkeys.push "p#{i}"
end
taxes = arg3.split('..').map{|d| Integer(d)}
(taxes[0]..taxes[1]).each do |i|
validkeys.push "t#{i}"
end
validkeys.each do |key|
json[arg1].keys.include?(key).should be_true
end
end
Now this script works fine except that if any one key is missing it doesn't state which one is missing. Either it passes or fails as assertions are iterated for each key.
I would like to know if there is any possibility of sending keys which are found ok to result stream. Thus my intention is to know to which keys are ok and which failed and which one skipped. As such order of keys is not expected in json.
Thanks in advance.
It's probably best to split the step definitions first:
And "standardorder" should be received
And the order should include parts 1 to 4
And the order should include taxes 1 to 3
And the order should include the total
Then you can re-use the steps elsewhere.
The 'order' check easy to implement as you're just checking one element.
For the other two, you are really just checking the presence of items in an array, e.g.:
actual_values.should == expected_values
If that fails, RSpec will give you a report showing how the arrays differ.
I have the following helper method that returns the value from a field.
public static string GetValueFrom(SPListItem item, string fieldName)
{
string value = string.Empty;
if (item.Fields.ContainsField(fieldName))
{
SPField field = item.Fields.GetField(fieldName);
if (item[field.InternalName] != null)
{
value = item[field.InternalName].ToString();
}
}
return value;
}
However for one Field (normal Choice Field) I am getting a ArgumentExecption on this line
if (item[field.InternalName] != null)
I am using
SPListItem item = list.GetItemById(itemId);
To get the item.
I cant find why I am getting the exception when I am checking to see if the field exists?
Any ideas as to why I am getting this Exception for only one field.
Update.
When debugging
The call to GetField() returns the correct field object.
Field.InternalName contains the correct Internal name of the field
If I try and access the value using item["internal name of the field"] it still throws and exception for only this one field.
Sometimes strange things happens and we do not have logical answer to those questions. Try by deleting the list and then creating the list again from scratch. DO NOT try to save it as template and DO NOT try to create the list from that template.
One possible reason of such type of ugly messages is that the security/permissions are not allowing to manipulate that field/column.
Another possible reason of such type of unwanted/unexpected messages is that when the field was created for the first time, its data type was different and later on it was changed to choice. Technically there should be no problem in doing so but sometimes we face odd behavior.
Have you tried debugging? Questions you should answer (because we can't):
Is field a valid value, or null, after the call to GetField()?
If field is not null, what does field.InternalName actually return?
If field.InternalName returns a valid value, can you access it by hard-coding that value in the indexer? i.e. item["fieldInternalName"]
Finding that information may help you solve the problem yourself, but if it doesn't add it to your post so the community has a better chance of helping you.
I do experienced this many a times. The reason for this is if you are logged-in as a non Admin Account(System Account) the default List View Lookup Threshold for the User is 8 for the lookup columns. i.e for the default view the user can access upto the 8 lookup fields only. If you change the List Throttling to >8 it will be resolved. But increasing this will degrade the performance.
Go to Central Admin >> Manage Web Applications >> Select the Web Application >> General Settings Dropdown >> Resource Throttling >> Change the "List View Lookup Threshold" to more than 8
Thanks,
-Codename "Santosh"