Questions tagged [model]
Part of the MVC pattern, the Model manages the behaviour and data of the application.
21,475
questions
73
votes
5
answers
40k
views
Should I make a DateRange object?
A few of my domain objects contain date ranges as a pair of start and end date properties:
public class Period {
public DateTime EffectiveDate { get; set; }
public DateTime ThroughDate { get; set;...
- 26.3k
72
votes
3
answers
23k
views
Where Should Model State Be Stored In Angular.js
I'm finding Angular's use of models confusing. Angular seems to take the approach that a model can be anything you like - I.E. Angular does not include an explicit model class and you can use vanilla ...
- 43.4k
70
votes
5
answers
33k
views
DDD and MVC: Difference between 'Model' and 'Entity'
I'm seriously confused about the concept of the 'Model' in MVC. Most frameworks that exist today put the Model between the Controller and the database, and the Model almost acts like a database ...
- 3,205
68
votes
5
answers
88k
views
Populating django field with pre_save()?
class TodoList(models.Model):
title = models.CharField(maxlength=100)
slug = models.SlugField(maxlength=100)
def save(self):
self.slug = title
super(TodoList, self).save()
...
- 12.2k
68
votes
3
answers
26k
views
How to know whether a model is new or not?
class Post < ActiveRecord::Base
end
post = Post.new
How do I judge whether the 'post' is a new model which is not pulled from the database?
- 3,503
67
votes
9
answers
91k
views
How I can put composite keys in models in Laravel 5?
I have in my DataBase a table with two primary keys (id and language_id) and I need put it in my models. The default primaryKey in Models (Model.php in Laravel 5) is id, and I want that the ...
- 831
66
votes
8
answers
52k
views
Rails after_initialize only on "new"
I have the following 2 models
class Sport < ActiveRecord::Base
has_many :charts, order: "sortWeight ASC"
has_one :product, :as => :productable
accepts_nested_attributes_for :product, :...
- 23.5k
65
votes
2
answers
70k
views
When to use Class or Interface in Angular project? [closed]
I’m here today because I’ve a question about, like the title said, about classes and interfaces in Angular.
From my Point of View, I understand this:
Interfaces are used in Typescript to perform ...
- 883
65
votes
4
answers
122k
views
Email model validation with DataAnnotations and DataType
I have following model:
public class FormularModel
{
[Required]
public string Position { get; set; }
[Required]
[DataType(DataType.EmailAddress)]
public string Email { get; set; }
...
- 777
65
votes
3
answers
44k
views
How can I iterate over ManyToManyField?
A simple question and yet I can't find an answer for it.
I have a model with a ManyToMany field:
class Stuff(models.Model):
things = models.ManyToManyField(Thing)
then in a different function I ...
- 10.1k
65
votes
1
answer
14k
views
Is it bad practice to include non-validating methods in a pydantic model?
I'm using pydantic 1.3 to validate models for an API I am writing.
Is it common/good practice to include arbitrary methods in a class that inherits from pydantic.BaseModel?
I need some helper methods ...
- 653
64
votes
11
answers
22k
views
Custom tag helper not working
I followed a few guides on creating a custom tag helper for ASP Core.
This is my helper:
using Microsoft.AspNetCore.Mvc.ViewFeatures;
using Microsoft.AspNetCore.Razor.TagHelpers;
using System;
...
- 2,995
61
votes
14
answers
72k
views
PHPStorm is not recognizing methods of my Model class in Laravel 5.0 [duplicate]
failed insert data into database, and all query class and Model class's method not found show in IDE (phpStrom) how can I solve it?
here is my extended class (Post.php) here show error in latest and ...
- 1,253
60
votes
9
answers
35k
views
Can Django automatically create a related one-to-one model?
I have two models in different apps: ModelA and ModelB. They have a one-to-one relationship. Is there a way django can automatically create and save ModelB when ModelA is saved?
class ModelA(models....
- 601
59
votes
6
answers
65k
views
Rails has_many with dynamic conditions
What I want is to create a Model that connects with another using a has_many association in a dynamic way, without the foreign key like this:
has_many :faixas_aliquotas, :class_name => 'Fiscal::...
- 8,418
59
votes
4
answers
29k
views
How to automatically create an initializer for a Swift class?
UPDATE:
Use structs and not classes. Struct is better in many ways has got an initializer of its own.
This is my model class. Is it possible to create the init method automatically? Everytime I have ...
- 2,177
59
votes
5
answers
92k
views
How to set a default attribute value for a Laravel / Eloquent model?
If I try declaring a property, like this:
public $quantity = 9;
...it doesn't work, because it is not considered an "attribute", but merely a property of the model class. Not only this, but also I ...
- 20.4k
58
votes
3
answers
78k
views
Ruby on Rails: errors.add_to_base vs. errors.add
I have read that errors.add_to_base should be used for errors associated with the object and not a specific attribute. I am having trouble conceptualizing what this means. Could someone provide an ...
- 18.9k
58
votes
1
answer
57k
views
Django model: NULLable field
I'm working on a django project where I need a DateField to sometimes be empty. My model looks like this:
#models.py
end = models.DateField(default=None, blank=True)
But when I run python manage.py ...
- 9,555
57
votes
6
answers
38k
views
How do you validate uniqueness of a pair of ids in Ruby on Rails?
Suppose the following DB migration in Ruby:
create_table :question_votes do |t|
t.integer :user_id
t.integer :question_id
t.integer :vote
t.timestamps
end
Suppose ...
- 20.6k
57
votes
7
answers
185k
views
Class 'App\Http\Controllers\DB' not found and I also cannot use a new Model
I have very basic problem. In L4 thes below methods worked out of the box, so now I am lost. Please help. A few days ago I started a Laravel 5.0 project. I have now fresh, clean installation.
Problem ...
- 2,692
57
votes
5
answers
14k
views
Should I avoid multi-table (concrete) inheritance in Django by any means?
Many experienced developers recommend against using Django multi-table inheritance because of its poor performance:
Django gotcha: concrete inheritance by Jacob Kaplan-Moss, a core contributor of ...
- 7,006
57
votes
8
answers
132k
views
How to delete a model using php artisan?
Is there a command to safely delete a model in Laravel 5? To create a model we use
php artisan make:model modelname
And that will create a model under app folder, and also a migration in database/...
- 6,992
55
votes
4
answers
20k
views
Do i need to create automapper createmap both ways?
This might be a stupid question! (n00b to AutoMapper and time-short!)
I want to use AutoMapper to map from EF4 entities to ViewModel classes.
1) If I call
CreateMap<ModelClass, ViewModelClass>...
- 6,021
54
votes
5
answers
18k
views
How do I get the default value for a field in a Django model?
I have a Django model with some fields that have default values specified. I am looking to grab the default value for one of these fields for us later on in my code. Is there an easy way to grab a ...
- 3,623
53
votes
2
answers
10k
views
How to translate model in Ruby class/module namespace?
I have a model Products::Car. How can I translate its attributes?
I have already tried this:
activerecord:
models:
products:
car: "Автомобиль"
attributes:
products:
car:
...
- 2,329
53
votes
9
answers
28k
views
DTO or Domain Model Object in the View Layer?
I know this is probably an age-old question, but what is the better practice? Using a domain model object throughout all layers of your application, and even binding values directly to them on the ...
- 9,537
52
votes
7
answers
46k
views
Generating Swift models from Core Data entities
Update for Xcode 8:
In Xcode 8, one needs to go to the Core Data Model Editor and Show the File Inspector. Near the bottom is an option for code generation. Select Swift.
Edit: I found the solution ...
- 5,129
51
votes
5
answers
42k
views
How to add boolean required attribute in mvc?
I have one model class like:
public class Student
{
[DataType(DataType.Date)]
[DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}", ApplyFormatInEditMode = true)]
[Display(Name = "...
- 2,652
51
votes
8
answers
25k
views
Rails Model has_many with multiple foreign_keys
Relatively new to rails and trying to model a very simple family "tree" with a single Person model that has a name, gender, father_id and mother_id (2 parents). Below is basically what I want to do, ...
- 1,285
51
votes
3
answers
58k
views
Local functions in Python [duplicate]
In the following Python code, I get an UnboundLocalError. As I understand it, local functions share the local variables of the containing function, but this hardly seems to be the case here. I ...
- 115k
51
votes
3
answers
51k
views
Rails model validation on create and update only
If I want to have validation only on create, then I can do
validates_presence_of :password, :on => :create
But how do I say on create and update? I tried this but it didn't work:
...
- 86.4k
50
votes
4
answers
20k
views
How do I prevent deletion of parent if it has child records?
I have looked through the Ruby on Rails guides and I can't seem to figure out how to prevent someone from deleting a Parent record if it has Children. For example. If my database has CUSTOMERS and ...
- 780
50
votes
2
answers
55k
views
optional fields in django models
I have the following model in django.
class Link(models.Model):
name = models.CharField(max_length=100)
url = models.CharField(max_length=100)
tag = models.CharField(max_length=100)
...
- 13.4k
50
votes
6
answers
28k
views
Create Ruby on Rails views (only) after controllers and models are already created
I've obtained a project that have controllers (minimal code only) and models, but the views are missing. Is there a way to generate the views only using scaffold or another tool?
- 2,038
49
votes
7
answers
12k
views
MVC: Data Models and View Models
I've read some MVC advice in the past regarding models stating that you should not reuse the same model objects for the domain and the view; but I haven't been able to find anyone willing to discuss ...
- 35.7k
48
votes
3
answers
111k
views
Create Models from database in Laravel
Is there some way to generate models from database in Laravel?
The generators package only create an empty model.
- 2,247
48
votes
2
answers
43k
views
How can I fill up form with model object data?
I want to fill up form with data from model instance. But my form has less fields than model. If I have code like this:
class Item(models.Model)
name = models.CharField(max_length=100)
price =...
- 6,375
47
votes
16
answers
187k
views
CodeIgniter PHP Model Access "Unable to locate the model you have specified"
I have been trying to load some models for this website I am building. However, for an unknown reason, it will bring the following error :
An Error Was Encountered
Unable to locate the model you ...
- 825
47
votes
4
answers
107k
views
Check if laravel model got saved or query got executed
I've seen alot of people using this way to check if a laravel model got saved. So now I wonder if it is a safe way.
And also can I check if the queries bellow got executed like this
Check if model ...
- 8,495
47
votes
3
answers
78k
views
ValueError - Cannot assign: must be an instance
I get the following error when I try to run an insert into one of my tables.
Cannot assign "1": "Team.department_id" must be a "Department" instance
Admittedly I'm ...
- 629
46
votes
6
answers
55k
views
Magento - Passing data between a controller and a block
Really quick and simple question but I can't find a decent answer to this - What is the best way to pass data from a controller to a block in Magento.
Incase it makes a difference, I am loading the ...
- 10.1k
46
votes
4
answers
47k
views
Do properties work on Django model fields?
I think the best way to ask this question is with some code... can I do this:
class MyModel(models.Model):
foo = models.CharField(max_length = 20)
bar = models.CharField(max_length = ...
- 75.7k
44
votes
4
answers
138k
views
MVC 4 - how do I pass model data to a partial view?
I'm building a profile page that will have a number of sections that relate to a particular model (Tenant) - AboutMe, MyPreferences - those kind of things. Each one of those sections is going to be a ...
- 5,554
44
votes
4
answers
59k
views
How does one add an attribute to a model?
In rails I generate a model with two strings and would like to add more. How would I go about doing this?
- 1,505
44
votes
3
answers
50k
views
Django Pass Multiple Models to one Template
I am building an address book that includes the relationships between entries, etc. I have separate models for Individuals, Companies, Venues, and Roles. On my index page I would like to list all of ...
- 1,235
44
votes
7
answers
73k
views
What is the difference between model.fit() an model.evaluate() in Keras?
I am using Keras with TensorFlow backend to train CNN models.
What is the between model.fit() and model.evaluate()? Which one should I ideally use? (I am using model.fit() as of now).
I know the ...
- 1,920
43
votes
3
answers
72k
views
Restrict django FloatField to 2 decimal places
I am looking for a way to limit the FloatField in Django to 2 decimal places. Has anyone got a clue of how this could be done without having to use a DecimalField?
I tried decimal_places=2, but this ...
- 1,012
43
votes
6
answers
75k
views
How can I change a Django form field value before saving?
if request.method == 'POST':
userf = UsersModelForm(request.POST)
username = userf.data['username']
password = userf.data['password']
passwordrepeat = userf.data['passwordrepeat']
...
- 12.3k
43
votes
1
answer
33k
views
Instance the query builder directly from model
When I do something like SomeModel::with('user') it returns a Query\Builder instance. How can I get this instance without need call the with() (or similar)?
For instance, I tried it: new SomeModel, ...
- 12.3k