model
Rails: change column type, but keep data
A standard migration using the change_column method will convert integers to strings without any data loss. rake db:rollback will also do the reverse migration without error if required. Here is the test migration I used to confirm this behaviour: class ChangeAgeToString < ActiveRecord::Migration def self.up change_column :users, :age, :string end def self.down change_column :users, :age, … Read more
difference between scaffold and model in Rails
When you generate a model, you get a model as well as some related components. One of my favorite ways of explaining topics like this is to actually try it out or encourage others to try it, so if I were to enter the command rails generate model Foo name:string description:text within a Rails project, … Read more
Real example of TryUpdateModel, ASP .NET MVC 3
Since the OP asked, here’s an example of the ViewModel pattern, or as I like to call it – ASP.NET MVC done properly. So why use a view specific model You should only pass the information to your view that it needs. Often you’ll need to add additional view-meta-data (such as title/description attributes). These do … Read more
What is DOM? (summary and importance)
In general terms a DOM is a model for a structured document. It is a central concept in today’s IT and no developer can opt out of DOM. Be it in .net, in HTML, in XML or other domains where it is used. It applies to all documents (word documents, HTML pages, XML files, etc). … Read more
MVC :: What is a model?
The MVC paradigm is a design pattern where you organize your application in with the following structure. The Model: this is where you should keep your data model, the algorithms. For example if you write a spreadsheet application, you would keep the data structure of your spreadsheet. You would have the computation engine in your … Read more
How to set initial data for Django admin model add instance form?
Alasdair’s approach is nice but outdated. Radev’s approach looks quite nice and as mentioned in the comment, it strikes me that there is nothing about this in the documentation. Apart from those, since Django 1.7 there is a function get_changeform_initial_data in ModelAdmin that sets initial form values: def get_changeform_initial_data(self, request): return {‘name’: ‘custom_initial_value’}
This expression is not callable. Type ‘Number’ has no call signatures
I was getting this error as well, and realized I’d just forgotten to import Response. Adding an import line solved the problem for me. import express, {Request, Response} from ‘express’;