Rails controller create action difference between Model.new and Model.create

Question

I'm going through a few Rails 3 and 4 tutorial and come across something I would love some insights on:

What is the difference between the Model.new and Model.create in regards to the Create action. I thought you do use the create method in the controller for saving eg. @post = Post.create(params[:post]) but it looks like I'm mistaken. Any insight is much appreciated.

Create action using Post.new

def new
  @post = Post.new
end

def create
  @post = Post.new(post_params)
  @post.save

  redirect_to post_path(@post)
end

def post_params
  params.require(:post).permit(:title, :body)
end

Create action using Post.create

def new
  @post = Post.new
end

def create
  @post = Post.create(post_params)
  @post.save

  redirect_to post_path(@post)
end

def post_params
  params.require(:post).permit(:title, :body)
end

I have two questions

• Is this to do with a Rails 4 change?
• Is it bad practice to use @post = Post.create(post_params)?

Answer 1

Model.new

The following instantiate and initialize a Post model given the params:

@post = Post.new(post_params)

You have to run save in order to persist your instance in the database:

@post.save

Model.create

The following instantiate, initialize and save in the database a Post model given the params:

@post = Post.create(post_params)

You don't need to run the save command, it is built in already.

More informations on new here

More informations on create here