Can active record queries be used in controller action? - activerecord

Question

I have a controller​ action which requires to find data from existing database. I am still learning rails and recently came to know about active record queries.
But I am not sure how to use it to fetch record from database in a controller action.
Can anybody please explain this with some example?
Thanks in advance

Answer 1

I found the answer. We can use active record queries to fetch the record from the database in the controller. Example is as follow:
Consider a database 'Dress' which has color attribute. Now I want to fetch all the 'dresses' which have orange color. So the query will be as:
#dresses = Dress.where(color: 'orange')
This will fetch all the record of dresses which have color = orange.

Answer 2

Yes you can used active record query inside controller. But better to put active record query logic inside model only. Because rails follow MVC Architecture
MVC stands for Model, View and Controller. MVC separates application into three components - Model, View and Controller.
Model: Model represents shape of the data and business logic. It maintains the data of the application. Model objects retrieve and store model state in a database. Model is a data and business logic.
View: View is a user interface. View display data using model to the user and also enables them to modify the data.
Controller: Controller handles the user request. Typically, user interact with View, which in-turn raises appropriate URL request, this request will be handled by a controller. The controller renders the appropriate view with the model data as a response.
Example:-
class RoomsController < ApplicationController
before_action :set_room, only: [:show, :edit, :update, :destroy]
# GET /rooms
# GET /rooms.json
def index
#rooms = Room.all
end
# GET /rooms/1
# GET /rooms/1.json
def show
end
# GET /rooms/new
def new
#room = Room.new
end
# GET /rooms/1/edit
def edit
end
# POST /rooms
# POST /rooms.json
def create
#room = Room.new(room_params)
respond_to do |format|
if #room.save
format.html { redirect_to #room, notice: 'Room was successfully created.' }
format.json { render :show, status: :created, location: #room }
else
format.html { render :new }
format.json { render json: #room.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /rooms/1
# PATCH/PUT /rooms/1.json
def update
respond_to do |format|
if #room.update(room_params)
format.html { redirect_to #room, notice: 'Room was successfully updated.' }
format.json { render :show, status: :ok, location: #room }
else
format.html { render :edit }
format.json { render json: #room.errors, status: :unprocessable_entity }
end
end
end
# DELETE /rooms/1
# DELETE /rooms/1.json
def destroy
#room.destroy
respond_to do |format|
format.html { redirect_to rooms_url, notice: 'Room was successfully destroyed.' }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_room
#room = Room.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def room_params
params.require(:room).permit(:name, :type, :user_id)
end
end