I can't seem to find a solution for the following in the django docs.
So for example, i have a field in Class table called department that points to Department database (foreignKey). If I create a admin interface for Class table called ClassAdmin(admin.ModelAdmin). Then i create an entry for Department class. Now automatically, when i try to create a new Class entry, it will show a dropdown menu for entries in Department. The problem arises when i try to do that, it would show something along the lines of "Department Object" for each entry in the dropdown. I would like a way to define canonical names for each entry for department (Department.name is the field i would like to use).
Does anyone know how to do that?
Thanks a lot!
Implement the __str__ method in your Department model:
def __str__(self):
return self.name
Related
I'm using a Rails application to access a Dynamics NAV Database (today is called Dynamics 365 Business Central). In order to make it multi tenant, they partition the DB using table name prefixes ex: Company 1$Warehouse Entry or Company 2$Warehouse Entry.
I wanted to use a field defined in my User model in order to set the company name that it access.
In order to access the current user in the model I have used the following on application_controller.rb
before_action -> { User.current = current_user }
And then I set a base class where it declares the following instance method:
def self.set_company_name
company = User.current.nav_company ? User.current.nav_company + "$" : "Company 1$"
self.table_name = company + self.table_name
end
I also tried to use instance variables ##company but after reading I saw that table names in rails are cached.
What I have done works, but only if you restart the application. The table name doesn't change in runtime.
How can I make it dynamic? I saw this Question but the answer didn't show how to do this.
I don't know anything about Dynamics 365 and I don't understand why you want to associate two tables to one model, but I have worked with schemas/namespaces in postgresql for example: config.users where config is the schema and users the table name; so you can use it like select * from config.users.
Rails can easily adapt to this struct like you can see here.
I have 2 domain classes
Expenditure
class Expenditure {
Date date
Supplier supplier
String particular
BigDecimal amount
}
Supplier
class Supplier {
String name
String address
static hasMany = [expenditures: Expenditure]
}
What happening is that when I create a new expenditure, I will enter the supplier from the list of suppliers in the Supplier class. When the supplier is not exist, I will have to create it first and then select it when creating the expenditure.
What I want is that, when I enter the supplier it will be looked up, and when not found, it will be created on the go (when saving the expenditure instance) without me having to create it first in the Supplier table and then come back to Expenditure to complete the form.
How can I achieve this?
What I want is that, when I enter the supplier it will be looked up,
and when not found, it will be created on the go
One option you have is to do something like one of these...
Supplier.findOrCreateByName('some name goes here')
Supplier.findOrCreateByNameAndAddress('some name goes here', 'some address goes here')
There are also findOrSaveBy... counterparts but those only work if you are supplying enough search criteria to create a fully save-able instance.
I hope that helps.
While I'm experienced with Java, I am a Grails newbie but I am trying to get into it. I set up a basic "School" application containing the following domains:
Student
Class
Attendance
Both the 'Student' and 'Class' domains are scaffolded. Now, I want to create the 'Attendance' domain, and I'm going to need a controller with a custom view. I can do that, I'm just looking to understand (at a high level) the best way to set up the view (let's call it 'attendance.gsp').
The view will contain a dropdown box to select a class. Once a class is selected, I want to populate a table. The first column will contain the list of students in the class, and the second column will contain "Attended?" checkboxes.
I think that I can at least get that far.
I am wondering how to go about relating the checkbox value to the student. Since this class is not scaffolded, no attendance column has been created in the database. Do I need to have anything defined in the Attendance domain? How might you go about doing this? Can anyone recommend a particular example online that is doing something similar?
Thanks!
Something like this:
class Class {
...
static hasMany = [sessionsAttendance: Attendance]
}
class Student {
....
}
class Attendance {
static hasMany = [studentsAttended: Student]
}
I have a model, called Organisation and the model is stored in an assembly called Model. There is a requirement to insert an organisation and update an organisation.
Couple of questions:
When inserting a new organisation, I want to ensure that the organisation doesn't already exist so I've inserted some remote validation. I then bind the model to the insert view.
Now, when I'm creating the update view should I use a different view model which removes the remote validation for duplicate organisation names? If so, I can't use my base Organisation model for the update view, so do I then need to create 2 different views, one for insert and one for update? If this is the case, there is going to be 2 views that are basically the same but just use different models.
Can anyone help?
For this specific scenario the validation that no other organization with the same name exists seems valid for both the insert and update case so you could reuse the same view model.
However validating that the name does not exists when updating a organization must have extra because if the user does not change the organization name then at least one record on the database has that name, the one being updated, and the validation should ignore that record.
So if you choose to reuse the view model the validation must perform according to the context of the operation (insert or update).
Question 1: check validation:
If their is something not valid, do this:
If(isNotValid()){
ModelState.AddModelError("Key", "The user name or password provided is incorrect.")
}
Key is the field in your view that is incorrect.
Question 2: Difference between Create / Edit
You should use the same ViewModel, because in your update, they can still change the "Organisation Name" and you should still check if it is unique.
But why should you use a ViewModel just to check the validation? Is there a reason why you can't check the organisation names for uniqueness in your controller and do a ModelState.AddModelError when it is not unique?
A ViewModel is when you have to extend the Page, For Example
public class DashBoardViewModel
{ public List(Of Organisation) Organisation {get;set;}
public List(Of Staff) Staff{get;set;}
public List(Of Assignment) Assignments{get;set;}
}
Above would be a fictional DashBoardViewModel where i show all the Organisations, Staff and Assignments.
A ViewModel doesn't contain just one type of object, it contains multiple.
And don't forget, sometimes when you need to add some data to a View, you could just use ViewData or ViewBag, instead of creating a ViewModel.
I have a model, Docs, with a guid column, author_id, which should reference a MembershipUser.
I'm using the standard MembershipProvider (I only changed the db name), and of course I haven't a model for MembershipUsers.
I can easily define some methods in class Docs to get MembershipUser for a Doc and all Docs for a MembershipUser, but some things are tricky (listing users, show how many docs each user has); furthermore, I feel I'm using MVC in an odd way: it seems to me that it would be easier if I had a MembershipUsers model...
How can I implement this relationship? Should I implement a model for MembershipUsers?
thanks
update: I realize I wasn't clear at all.
Say I want to list all my users and their docs.
One way to do this is:
ViewModel model = new ViewModel()
{
Users = from MembershipUser user in Membership.GetAllUsers(page, pagesize, out totalusers)
select new UserWithDocs
{
User = user,
Docs = context.Docs.Where(c => c.author_id == (Guid) user.ProviderUserKey)
},
UsersCount = totalusers
};
This works, but generates one separate query for each user.
I could get an array of users' guids and then query for Docs where author_id IN list_of_guids, but then I should manually associate each doc to its author.
What is a better solution?
not sure if i understand you correctly, but you can use the MembershipUser class as your model for users. if you want to reference user to your "doc" model, you can simply add a property "Author" to you model class and when you fetch the model from DB you can get the user as well.
the Membership class contains some static methods to list all users, add/delete users etc.