Hello guys i am using this code to fetch the Result from Coredata
func getRequest(entiryDesc:NSEntityDescription) -> NSFetchRequest{
var request:NSFetchRequest = NSFetchRequest()
request.entity = entiryDesc
request.resultType = NSFetchRequestResultType.DictionaryResultType
return request
}
Now the problem is i need All the attributes which contains the Nil value too but the excutefetchrequest returns only those properties which have values , is there any work around for this to return Null attributes with String like "" every time i fetch ? Thanks Advanced
Of course, you can just dispense with the .DictionaryResultType and fetch normal managed objects. There are very few cases where the dictionary result type makes sense.
If you want to construct a dictionary with all attributes filled out (for whatever opaque reason), remember two things:
Make sure to insert the null values as objects NSNull()
You can use the NSEntityDescription API to generate all the attribute keys. Use entityDescription.propertiesByName.allKeys to generate a list of all attribute names of your entity.
Related
How is the difference between this two news?
New
ProductId = &ProductId
ProductPriceListDate = &Today
ProductPriceListPrice = &price
EndNew
and
&Product = new()
&Product.ProductId = &ProductId
&Product.ProductPriceListDate = &Today
&Product.ProductPriceListPrice = &price
commit
Supossing i don't fill this properties, in both way the record will be inserted with null or it will be inserted with empty ('') and 0?
First option is inserting a record directly in the database and null or empty value will be used depending on Initialize not referenced attritutes property.
Second option I think that you're using a Business Component. This case is quite different because is not only inserting a record but triggering transaction rules.
Anyway, in this case "empty" is stored
Note: it seems that you forgot to include save() method in the second option.
Is there a way to restrict the "columns" returned from a Realm Xamarin LINQ query?
For example, if I have a Customer RealmObject and I want a list of all customer names, do I have to query All<Customer> and then enumerate the results to build the names list? That seems cumbersome and inefficient. I am not seeing anything in the docs. Am I missing something obvious here? Thanks!
You have to remember that Realm is an object based store. In a RDBMS like Sqlite, restricting the return results to a sub-set of "columns" of an "record" makes sense, but in an object store, you would be removing attributes from the original class and thus creating a new dynamic class to then instantiate these new classes as objects.
Thus is you want just a List of strings representing the customer names you can do this:
List<string> names = theRealm.All<Customer>().ToList().Select(customer => customer.Name).ToList();
Note: That you take the Realm.All<> results to a List first and then using a Linq Select "filter" just the property that you want. Using a .Select directly on a RealmResults is not currently supported (v0.80.0).
If you need to return a complex type that is a subset of attributes from the original RealObject, assuming you have a matching POCO, you can use:
var custNames = theRealm.All<Customer>().ToList().Select((Customer c) => new Name() { firstName = c.firstName, lastName = c.lastName } );
Remember, once you convert a RealmResult to a static list of POCOs you do lose the liveliness of using RealmObjects.
Personally I avoid doing this whenever possible as Realm is so fast that using a RealmResult and thus the RealObjects directly is more efficient on processing time and memory overhead then converting those to POCOs everytime you need to new list...
in my Spring MVC project i m using Hibernate, by using Criteria API i am applying Group BY and Order BY clause. Query get executed on DB successfully and it brings result also but its an array of Object--
Here is code of Criteria API
Criteria criteria = session.createCriteria(DashboardSubindicatorSubmission.class, "DashboardSubindicatorSubmission")
.setProjection(Projections.projectionList()
.add(Projections.sum("InputValue").as("InputValue"))
.add(Projections.groupProperty("fkAccademicYearId"))
.add(Projections.groupProperty("fkAssessmentPlanID"))
.add(Projections.groupProperty("fkSubindicatorID"))
.add(Projections.groupProperty("InputTitle")))
.addOrder(Order.asc("fkAccademicYearId"))
.addOrder(Order.asc("fkAssessmentPlanID"))
.addOrder(Order.asc("InputTitle"));
List<DashboardSubindicatorSubmission> dashboardSubindicatorSubmissionList = (List<DashboardSubindicatorSubmission>)criteria.list();
session.flush();
transaction.commit();
return dashboardSubindicatorSubmissionList;
I am casting criteria.list() to List<DashboardSubindicatorSubmission> but when i try to do dashboardSubindicatorSubmissionList.get(i) on controller it gives me exception java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to mkcl.accreditation.model.DashboardSubindicatorSubmission.
i come to know that, though i m casting it to List<DashboardSubindicatorSubmission> still its an list of object[] thats why i cant do dashboardSubindicatorSubmissionList.get(i) because it returns me object of DashboardSubindicatorSubmission. (Correct me if i am wrong)
So how can i convert my result into list of DashboardSubindicatorSubmission class?
Does setResultTransformer() helps me in this case?
You have two options. When you use projections, Hibernate doesn't know how to respect each field because it uses the name of each field to build objects and he doesn't know the names yet.
Thus, your first option is to name the fields grouped so that they match the names of object properties. This is necessary even if the string you use in projection is already the name of the object field. Something like:
.add(Projections.groupProperty("fkAccademicYearId"), "fkAccademicYearId") // same value
.add(Projections.groupProperty("fkAssessmentPlanID"), "other") // other value
The second option is to do what you yourself suggested, create your own implementation of ResultTransformer. I reckon this a interesting option if you want to extract other object of this query, as when you make a report.
LINQ newbie here
I am trying to get a value of a field - using a fieldName variable.
If I do a watch on row[FieldName] I do get a value - but when I do it on the actual code it will not compile.
string fieldName = "awx_name"
List<awx_property> propertyQry =
(
from property in crm.awx_propertyawx_properties
where property.awx_propertyid == new Guid(id)
select property
).ToList();
foreach (awx_property row in propertyQry)
{
//THIS DOES NOT WORK
fieldValue = row[fieldName];
}
Thanks in advance. Alternatives would be welcome as well
You keep us guessing what you are trying to do here... You need to specify the types of the objects, so it's easy for us to understand and help. Anyway, I think you are trying to get an object based on the ID. Since you are getting by Id, my guess would be the return value is a single object.
var propertyObj =( from property in crm.awx_propertyawx_properties
where property.awx_propertyid == new Guid(id)
select property
).SingleOrDefault();
if(propertyObj != null) {
fieldValue = propertyObj.GetType().GetProperty(fieldName).GetValue(propertyObj, null);
}
Of course, you need to add validation to make sure you don't get null or any other error while accessing the property value.
Hope it helps.
What type is fieldValue? What does awx_property look like? This will only work is awx_property is a key/value collection. It its not, you could use reflection instead.
If it is a key/value collection you are probably missing a cast. (row[FieldName].ToString() or something) Also you are missing a semi-colon in the foreach block.
I have a class MyObj and a collection IEnumerable.
Some of the columns are wholly empty (i.e. == NULL) across all rows and therefore I want to create an IEnumerable<> of the members of MyObj which hold a non-null value.
If I could predict the members of MyObj which would be of interest I'd do something like:
var part =
from entry in iList
select new {entry.a, entry.c, entry.s};
...but I don't know which members of MyObj I'm interested in at design time - I only know that at runtime.
How can I construct my list??
Thanks,
Tamim Sadikali.
Your question does not make sense.
You're trying to create a type whose members are only known at runtime.
What would you do with the results?
You would not be able to access any properties of the result objects because they might not exist.
If you want to display the data in a grid, and you don't want to display columns which are entirely null, then you should bind the original collection to the grid, then hide some of the columns in the grid.
Wait for release of VS2010, C# 4.0 with it's 'dynamic' type should solve your problem. (Or maybe help you shoot yourself in the foot).
If you are doing this for UI, better hide columns that contain all nulls. For DataGridView in WinForms it may look like this:
foreach (DataGridViewColumn column in dataGridView.Columns)
if (dataGridView1.Rows.Cast<DataGridViewRow>().All(r => r.Cells[column.Name].Value == null))
column.Visible = false;