[RAILS] About ruby form

form_for Methods that allow you to create form tags in Rails Form_for for user registration and information update function, form_tag for search function

form_for argument

Specify the model instance as an argument.

A model instance is an instance of a class that you want to save in the database.


<%= form_for(@user) do |f| %>
  <%= f.text_field :name %>
  <%= f.submit %>
<% end %>

In form_for, the path destination is not specified like form_tag.


def new
  @user = User.new
end

def edit
  @user = User.find(params[:id])
end

The instance created by the controller is created by the new method, and if it does not have the information, it is assigned to the create action, and if it already has the information, it is assigned to the update action.

How to create a post form with form_for

Describe as "f.html tag name: column name".


<%= form_for(@user) do |f| %>
  <%= f.text_field :name %>
  <%= f.submit %>
<% end %>

In the above example, it is saved in the name column of the user table.

html tags that can be used in form_for

・ Form_tag

Forms like search forms don't need a database, so use form_tag.

・ Url option

You can specify the action when <% = form.submit%> is pressed.


<%= form_for @fruit, url: fruit_bulk_create_path do |form| %>
<%= form.label :name %> <%= form.text_field :name, id: :fruit_name %>
<%= form.label :description %> <%= form.text_area :description, id: :fruit_description %>
<%= form.submit "Bulk registration" %>
<% end %>

In the above code, when "form.submit" is executed, the "fruit # fruit_bulk_create" action is executed.