CRUD代表创建, 读取, 更新和删除数据库中的数据。 Active Record自动允许应用程序读取和操作表中存储的数据。
在本教程中, 我们将使用MySQL数据库创建一个Rails CRUD。
步骤1创建一个新的Rails应用程序。
rails new crud
步骤2将目录更改为crud。
cd crud
步骤3转到应用程序中的Gemfile并添加以下内容。
gem 'grape'
步骤4转到应用程序中的config / application.rb文件, 然后添加以下内容。
config.paths.add File.join('app', 'api'), glob: File.join('**', '*.rb')
config.autoload_paths += Dir[Rails.root.join('app', 'api', '*')]
步骤5运行以下命令:
bundle install
步骤6转到app / views / layouts / application.html.erb并将以下行插入head标签。
<%= stylesheet_link_tag??? 'https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css' %>
<%= stylesheet_link_tag??? 'https://cdn.datatables.net/s/dt/dt-1.10.10, r-2.0.0/datatables.min.css' %>
步骤7转到app / views / layouts / application.html.erb并将以下行插入</ body>标记之前。
<%= javascript_include_tag 'https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js' %>
<%= javascript_include_tag 'https://cdn.datatables.net/s/dt/dt-1.10.10, r-2.0.0/datatables.min.js' %>
步骤8在上面的文件中, 将<%= yield%>替换为以下代码:
<div class="container">
<div><% if flash[:notice] %>
<div><%= flash[:notice] %></div>
<% end %> <%= yield %></div>
</div>
</div>
步骤9转到app / assets / javascripts / application.js并添加加载jQuery DataTable的javascript代码:
var ready = function() {
$('#products').DataTable({
"columnDefs": [
{ "width": "19%", className: "dt-body-center", "targets": -1 }, { "width": "10%", "targets": 0 }, { "width": "7%", "targets": 1 }, { "width": "20%", "targets": 2 }, { "width": "20%", "targets": 3 }, ]
});
}
$(document).ready(ready);
$(document).on('page:load', ready);
步骤10从控制台创建一个控制器。
rails g controller products index show new create edit update destroy
步骤11从控制台创建模型。
rails g model product name:string price:decimal short_description:text full_description:text
步骤12转到app / controllers / products_controller.rb并编写以下代码。
class ProductsController < ApplicationController
# GET method to get all products from database
def index
@products = Product.all
end
# GET method to get a product by id
def show
@product = Product.find(params[:id])
end
# GET method for the new product form
def new
@product = Product.new
end
# POST method for processing form data
def create
@product = Product.new(product_params)
if @product.save
flash[:notice] = 'Product added!'
redirect_to root_path
else
flash[:error] = 'Failed to edit product!'
render :new
end
end
# GET method for editing a product based on id
def edit
@product = Product.find(params[:id])
end
# PUT method for updating in database a product based on id
def update
@product = Product.find(params[:id])
if @product.update_attributes(product_params)
flash[:notice] = 'Product updated!'
redirect_to root_path
else
flash[:error] = 'Failed to edit product!'
render :edit
end
end
# DELETE method for deleting a product from database based on id
def destroy
@product = Product.find(params[:id])
if @product.delete
flash[:notice] = 'Product deleted!'
redirect_to root_path
else
flash[:error] = 'Failed to delete this product!'
render :destroy
end
end
# we used strong parameters for the validation of params
def product_params
params.require(:product).permit(:name, :price, :old_price, :short_description, :full_description)
end
end
步骤13转到app / models / product.rb并在名称, 价格和描述字段中进行一些验证。
class Product < ApplicationRecord
validates :name, presence: true
validates :price, presence: true, numericality: {:greater_than => 0}
validates :short_description, presence: true
end
步骤14转到config / routes.rb并添加:
resources :products
root 'products#index'
步骤14转到config / routes.rb并添加:
resources :products
root 'products#index'
步骤15现在在应用程序文件夹中创建一个名为api的文件夹。在此文件夹中, 创建一个名为product的文件夹。现在, 终于创建了app / api / products / products_api.rb文件并添加以下代码。
module Products
class ProductsAPI < Grape::API
format :json
desc "Product List", {
:notes => <<-NOTE
Get All Products
__________________
NOTE
}
get do
Product.all
end
desc "Product By Id", {
:notes => <<-NOTE
Get Product By Id
__________________
NOTE
}
params do
requires :id, type: Integer, desc: "Product id"
end
get ':id' do
begin
product = Product.find(params[:id])
rescue ActiveRecord::RecordNotFound
error!({ status: :not_found }, 404)
end
end
desc "Delete Product By Id", {
:notes => <<-NOTE
Delete Product By Id
__________________
NOTE
}
params do
requires :id, type: Integer, desc: "Product id"
end
delete ':id' do
begin
product = Product.find(params[:id])
{ status: :success } if product.delete
rescue ActiveRecord::RecordNotFound
error!({ status: :error, message: :not_found }, 404)
end
end
desc "Update Product By Id", {
:notes => <<-NOTE
Update Product By Id
__________________
NOTE
}
params do
requires :id, type: Integer, desc: "Product id"
requires :name, type: String, desc: "Product name"
requires :price, type: BigDecimal, desc: "Product price"
optional :old_price, type: BigDecimal, desc: "Product old price"
requires :short_description, type: String, desc: "Product old price"
optional :full_description, type: String, desc: "Product old price"
end
put ':id' do
begin
product = Product.find(params[:id])
if product.update({
name: params[:name], price: params[:price], old_price: params[:old_price], short_description: params[:short_description], })
{ status: :success }
else
error!({ status: :error, message: product.errors.full_messages.first }) if product.errors.any?
end
rescue ActiveRecord::RecordNotFound
error!({ status: :error, message: :not_found }, 404)
end
end
desc "Create Product", {
:notes => <<-NOTE
Create Product
__________________
NOTE
}
params do
requires :name, type: String, desc: "Product name"
requires :price, type: BigDecimal, desc: "Product price"
optional :old_price, type: BigDecimal, desc: "Product old price"
requires :short_description, type: String, desc: "Product old price"
end
post do
begin
product = Product.create({
name: params[:name], price: params[:price], old_price: params[:old_price], short_description: params[:short_description], })
if product.save
{ status: :success }
else
error!({ status: :error, message: product.errors.full_messages.first }) if product.errors.any?
end
rescue ActiveRecord::RecordNotFound
error!({ status: :error, message: :not_found }, 404)
end
end
end
end
步骤16转到config / routes.rb并添加以下代码。
mount Products::ProductsAPI => '/api/products'
步骤17在控制台中运行以下命令。
rake db:migrate
步骤18在app / views / products /文件中, 编写以下代码。
index.html.erb
<!DOCTYPE html>
<html>
<body>
<div class="container">
<h3>STOCK LIST</h3>
<div>
<%= link_to 'Add Product', new_product_path %>
</div>
<br>
<table border="2">
<thead>
<tr>
<th>Name</th>
<th>Price</th>
<th>Description</th>
<th>Actions</th>
</tr>
</thead>
<tbody>
<% @products.each do |product| %>
<tr>
<td><%= product.name %></td>
<td><%= product.price %></td>
<td><%= truncate(product.short_description, :length => 75) %></td>
<div>
<td>
<%= link_to 'Show', product_path(product) %>
<%= link_to 'Edit', edit_product_path(product) %>
<%= link_to 'Delete', product_path(product), method: :delete %>
</div>
</td>
</tr>
<% end %>
</tbody>
</table>
</div>
</body>
</html>
new.html.erb
<div class="container">
<%= form_for @product, url: {action: :create} do |f| %>
<div>
<h3>Add a Product</h3>
</div>
<div>
<p>
<%= "<div>#{@product.errors.full_messages.first}</div>".html_safe if @product.errors.any? %>
<div>
<label>Product Name</label>
<%= f.text_field :name %>
</div>
<div>
<label>Price</label>
<%= f.text_field :price %>
</div>
<div>
<label>Description</label>
<%= f.text_field :short_description %>
</div>
</p>
</div>
<div>
<%= link_to 'Back', { controller: 'products', action: 'index'} %>
<%= f.submit 'Create Product' %>
</div>
<% end %>
</div>
edit.html.erb
<div class =” container”> <%= form_for @product, 网址:{action::update} do | f | %> <h3>添加产品</ h3> <%=” <div>#{@ product.errors.full_messages.first} </ div>”。html_safe, 如果@ product.errors.any? %> <p> <div> <label>产品名称</ label> <%= f.text_field:name%> </ div> <div> <label> Price </ label> <%= f.text_field:price %> </ div> <div> <label>描述</ label> <%= f.text_field:short_description%> </ div> </ p> <div> <%= link_to’Back’, {controller:’产品”, 操作:’index’}%> <%= f。提交’Update Product’%> </ div> <%end%> </ div>
show.html.erb
<div class="container">
<h3>Add a Product</h3>
<div>
<label>Product Name</label>
<%= @product.name %>
</div>
<div>
<label>Price</label>
<%= @product.price %>
</div>
<div>
<label>Description</label>
<%= @product.short_description %>
</div>
<div>
<%= link_to 'Back', { controller: 'products', action: 'index'} %>
</div>
</div>
步骤19从命令行启动服务器。
rails s
步骤20在本地主机上运行该应用程序。
localhost:3000/products
将出现以下页面。在这里, 我们已经在表中插入了一些数据。
![Rails Ruby Rails Crud 1上](http://www.srcmini02.com/wp-content/uploads/2020/03/ruby-on-rails-crud1.png)
插入资料
![Rails Ruby Rails Crud 2上](http://www.srcmini02.com/wp-content/uploads/2020/03/ruby-on-rails-crud2.png)
要插入数据, 请单击以上快照中所示的”添加产品”。如下所示填写详细信息。
![Rails Ruby Rails Crud 3上](http://www.srcmini02.com/wp-content/uploads/2020/03/ruby-on-rails-crud3.png)
读取资料
要读取数据, 请单击操作显示。在这里, 我们将单击”跳伞表演”动作。
![Rails Ruby Rails Crud 4上](http://www.srcmini02.com/wp-content/uploads/2020/03/ruby-on-rails-crud4.png)
更新资料
要更新数据, 请单击”编辑操作”。在这里, 我们将编辑从男式正装衬衫到女式正装衬衫的衬衫描述。
![Rails Ruby Rails Crud 5上](http://www.srcmini02.com/wp-content/uploads/2020/03/ruby-on-rails-crud5.png)
![Rails Ruby Rails Crud 6上](http://www.srcmini02.com/wp-content/uploads/2020/03/ruby-on-rails-crud6.png)
删除资料
要删除数据, 请单击”删除”操作。在这里, 我们将从上表中删除产品牛仔裤。
![Rails Ruby Rails Crud 7上](http://www.srcmini02.com/wp-content/uploads/2020/03/ruby-on-rails-crud7.png)
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