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% Document Info
\author{Akshaya (akki\_1)}
\pdfinfo{
  /Title (ruby-on-rails-interview-questions.pdf)
  /Creator (Cheatography)
  /Author (Akshaya (akki\_1))
  /Subject (Ruby on rails interview Questions Cheat Sheet)
}

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    {\parbox{\dimexpr\textwidth-2\fboxsep\relax}{\noindent
        \hspace*{-6pt}\includegraphics[width=5.8cm]{/web/www.cheatography.com/public/images/cheatography_logo.pdf}}
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\begin{tabulary}{11cm}{L}
    \vspace{-2pt}\large{\bf{\textcolor{DarkBackground}{\textrm{Ruby on rails interview Questions Cheat Sheet}}}} \\
    \normalsize{by \textcolor{DarkBackground}{Akshaya (akki\_1)} via \textcolor{DarkBackground}{\uline{cheatography.com/208452/cs/44671/}}}
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  \mymulticolumn{2}{p{5.377cm}}{\bf\textcolor{white}{Cheatographer}}  \\
  \vspace{-2pt}Akshaya (akki\_1) \\
  \uline{cheatography.com/akki-1} \\
  \end{tabulary}
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  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Cheat Sheet}}  \\
   \vspace{-2pt}Published 17th November, 2024.\\
   Updated 17th November, 2024.\\
   Page {\thepage} of \pageref{LastPage}.
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  %\includegraphics[width=48px,height=48px]{dave.jpeg}
  Measure your website readability!\\
  www.readability-score.com
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\begin{multicols*}{3}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{What is Ruby on rails?}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{It is a Open-source web application framework written in ruby} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{* It is designed to make web applications easier by assuming what developers need to get started.} \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{* It follows the model-view-controller (MVC) architecture pattern.} \tn 
% Row Count 6 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{MVC Architecture}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{In Ruby, MVC (Model-View-Controller) is a pattern used to organize code, especially in web applications. It separates the application into three parts:} \tn 
% Row Count 4 (+ 4)
% Row 1
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{{\bf{Model}}: Handles data and business logic. For example, it communicates with the database.} \tn 
% Row Count 6 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{{\bf{View}}: Manages the display. It's what users see on the screen, like HTML or templates.} \tn 
% Row Count 8 (+ 2)
% Row 3
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{{\bf{Controller}}: Connects Model and View. It receives user input, tells the Model to update or retrieve data, and then decides what View to show.} \tn 
% Row Count 11 (+ 3)
% Row 4
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{{\bf{Flow}}: User -\textgreater{} Controller -\textgreater{} Model -\textgreater{} Controller -\textgreater{} View -\textgreater{} User.} \tn 
% Row Count 13 (+ 2)
% Row 5
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{In Ruby on Rails, this pattern helps keep code clean and organized, making it easier to manage large applications.} \tn 
% Row Count 16 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{MVC mean}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{MVC stands for Model-View-Controller. It's a software architectural pattern commonly used in the development of user interfaces, particularly for web applications.} \tn 
% Row Count 4 (+ 4)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Migration}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{It is a feature in rails that allow developers to manage \& modify database schema over time.} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{* They are Ruby files used to make changes to the database, like creating tables or adding/removing columns.} \tn 
% Row Count 5 (+ 3)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{* Migrations make it easier to track and version change, rollback changes if necessary} \tn 
% Row Count 7 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Why Migrations are important}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Migrations are important because they help track changes, keep the database schema consistent, and allow rolling back changes if needed.} \tn 
% Row Count 3 (+ 3)
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\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Rails controller \& purpose}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Rails {\bf{Controller }}handles requests and sends responses. It processes user actions, interacts with models to fetch or save data, and renders views or returns data (e.g., JSON).} \tn 
% Row Count 4 (+ 4)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{* Controllers are mapped to URLs using routes. They act as the middle layer between the user and the app's data or views.} \tn 
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% Row 2
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\mymulticolumn{2}{x{5.377cm}}{Ex: User visits /articles. router directs request to \seqsplit{ArticlesController\#index}, controller feteches all articles with Article.all, controller sends data to view /returns a response.} \tn 
% Row Count 11 (+ 4)
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\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Active Record}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Active Record is the ORM (Object-Relational Mapping) in Rails. It connects Ruby classes to database tables, making it easy to work with the database without writing SQL. Developers can use Ruby methods to interact with the data.} \tn 
% Row Count 5 (+ 5)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
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\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{How active record works in database?}}  \tn
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\mymulticolumn{2}{x{5.377cm}}{Maps models to database tables (e.g., User → users).} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Provides methods for CRUD operations create, find, update, destroy} \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Ex:  create(User.{\bf{create}}(name: " "), find(User.{\bf{find}}(1)), update(user.{\bf{update}}(name: " "), destroy(user.{\bf{destroy}}).} \tn 
% Row Count 7 (+ 3)
% Row 3
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\mymulticolumn{2}{x{5.377cm}}{Uses migrations to manage the database schema.} \tn 
% Row Count 8 (+ 1)
% Row 4
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\mymulticolumn{2}{x{5.377cm}}{Handles relationships with associations (e.g., has\_many, belongs\_to).} \tn 
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% Row 5
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Allows queries using Ruby methods instead of SQL.`User.where("age \textgreater{} ?", 18).order(:name)`} \tn 
% Row Count 12 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
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\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{ORM( \seqsplit{Object-Relational-Mapping)}}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{It allows developers to interact with database using ruby code instead of writing raw SQL queries.} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{* In Rails, the ORM is Active Record, which maps models to database tables and provides methods for performing CRUD operations (Create, Read, Update, Delete).} \tn 
% Row Count 6 (+ 4)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
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\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Gemfile}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{It is used to manage  the dependencies of a Rails application. It specifies which gems (libraries) the application depends on and their versions.} \tn 
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\hhline{>{\arrayrulecolor{DarkBackground}}--}
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\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Some Gem files}}  \tn
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\mymulticolumn{2}{x{5.377cm}}{{\bf{Authentication \& Authorization}}: : Devise} \tn 
% Row Count 1 (+ 1)
% Row 1
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\mymulticolumn{2}{x{5.377cm}}{* It handles user authentication(login, signup, password recover)} \tn 
% Row Count 3 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{Database \& ORM}}: bcrypt} \tn 
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\mymulticolumn{2}{x{5.377cm}}{* Handles password encryption when using has\_secure\_password} \tn 
% Row Count 6 (+ 2)
% Row 4
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{Frontend}}: Bootstrap} \tn 
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% Row 5
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{* Add bootstrap style for responsive web design.} \tn 
% Row Count 8 (+ 1)
% Row 6
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{Kamineri}}: Adds pagination to your application.} \tn 
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\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
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\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Routing}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{Routing connects incoming requests (URLs) to the specific controller actions. Rails uses a routes.rb file to define routes.} \tn 
% Row Count 3 (+ 3)
% Row 1
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{A route can be defined as:  get 'articles', to: 'articles\#index'} \tn 
% Row Count 5 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{- a GET request to /articles will be handled by the index action in the ArticlesController.} \tn 
% Row Count 7 (+ 2)
% Row 3
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{- Rails has RESTful routes, which map standard URL patterns to controller actions (e.g., index, show, create, etc.) based on resources:} \tn 
% Row Count 10 (+ 3)
% Row 4
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{resources :articles} \tn 
% Row Count 11 (+ 1)
% Row 5
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{- This generates routes for all CRUD actions (index, show, new, edit, create, update, destroy).} \tn 
% Row Count 13 (+ 2)
% Row 6
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{Routes ensure incoming requests are directed to the right controllers and actions, organizing the application's structure effectively.} \tn 
% Row Count 16 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{RESTful Architecture}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{RESTful architecture organizes web applications around resources and standardizes how they are accessed using HTTP verbs.} \tn 
% Row Count 3 (+ 3)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Resources: Treats entities (e.g., articles, users) as resources.} \tn 
% Row Count 5 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{HTTP Verbs: Maps actions to HTTP methods:} \tn 
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% Row 3
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{{\bf{GET}}: Retrieve data. {\bf{ POST}}: Create data. \{\{nl\}\}	{\bf{PUT/PATCH}}: Update data. {\bf{DELETE}}: Remove data.} \tn 
% Row Count 9 (+ 3)
% Row 4
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{RESTful Routes in Rails: Using resources, Rails generates routes for CRUD operations.} \tn 
% Row Count 11 (+ 2)
% Row 5
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{resources :articles} \tn 
% Row Count 12 (+ 1)
% Row 6
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{GET /articles → \seqsplit{ArticlesController\#index} (List all articles)} \tn 
% Row Count 14 (+ 2)
% Row 7
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{POST /articles → \seqsplit{ArticlesController\#create} (Create a new article).} \tn 
% Row Count 16 (+ 2)
% Row 8
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{GET /articles/:id → ArticlesController\#show (Show a specific article).} \tn 
% Row Count 18 (+ 2)
% Row 9
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{PATCH/PUT /articles/:id → \seqsplit{ArticlesController\#update} (Update an article).} \tn 
% Row Count 20 (+ 2)
% Row 10
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{DELETE /articles/:id → \seqsplit{ArticlesController\#destroy} (Delete an article).} \tn 
% Row Count 22 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
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\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
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\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Associations \& types}}  \tn
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\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{Associations }}define relationships between models. They allow models to connect and share data easily.} \tn 
% Row Count 3 (+ 3)
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\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{\{\{ac\}\}{\bf{Types}}} \tn 
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\mymulticolumn{2}{x{5.377cm}}{{\bf{has\_many}}: Defines one-to-many relationship. A model "has many" other models.\{\{nl\}\}	 Ex: User can have many Posts} \tn 
% Row Count 7 (+ 3)
% Row 3
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{{\bf{belongs\_to}}: Defines the opposite of has\_many. A model "belongs to" another model. \{\{nl\}\}Ex: Post belongs to User} \tn 
% Row Count 10 (+ 3)
% Row 4
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{has\_one}}: Defines a one-to-one relationship. A model "has one" other model. \{\{nl\}Ex: User has one Profile} \tn 
% Row Count 13 (+ 3)
% Row 5
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{{\bf{has\_and\_belongs\_to\_many}}:Defines a many-to-many relationship without a join model. \{\{nl\}\}	Ex: Student can have many Courses, and a Course can have many Students.} \tn 
% Row Count 17 (+ 4)
% Row 6
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{has\_many :through}}: Defines a many-to-many relationship with a join model.\{\{nl\}\}	 Ex: Doctor has many Patients through Appointments.} \tn 
% Row Count 20 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
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\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
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\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Polymorphic association}}  \tn
% Row 0
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\mymulticolumn{2}{x{5.377cm}}{1 table associated with many tables} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Ex: Post have likes, we use likes in post and comment} \tn 
% Row Count 3 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
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\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Active Record Vs Active Model}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{Active Record}}  is an ORM framework in Rails that connects classes to database tables, enabling database operations through Ruby objects} \tn 
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% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{{\bf{Active Model}} provides modules for building custom models without a database, offering features like validations, serialization, and callbacks.} \tn 
% Row Count 6 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
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\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{How do you handle errors?}}  \tn
% Row 0
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\mymulticolumn{2}{x{5.377cm}}{Error handling in Rails is important for providing a smooth user experience and ensuring that users are properly informed when something goes wrong.} \tn 
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\hhline{>{\arrayrulecolor{DarkBackground}}--}
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\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Partials}}  \tn
% Row 0
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\mymulticolumn{2}{x{5.377cm}}{Partials in Rails are reusable pieces of view code that can be shared across multiple templates. They help reduce code duplication and improve maintainability by breaking views into smaller, modular components.} \tn 
% Row Count 5 (+ 5)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{* Partial files start with an underscore (\_) in their filename, e.g., \_header.html.erb. They are called without the underscore, e.g., \textless{}\%= render 'header' \%\textgreater{}.} \tn 
% Row Count 9 (+ 4)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Sessions}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Sessions store user-specific data across requests, typically used for authentication and tracking user activity.} \tn 
% Row Count 3 (+ 3)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{In Rails, session data is stored in a cookie (by default) and is accessible using the session hash.} \tn 
% Row Count 5 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Use of  Rails console}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{The Rails console is an interactive command-line tool that allows developers to interact with their Rails application directly} \tn 
% Row Count 3 (+ 3)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{{\bf{Interacting with the Database}}:  Test queries and CRUD operations without writing a full script.} \tn 
% Row Count 5 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{Testing Code}}:  Run snippets of Ruby or Rails code to verify functionality.} \tn 
% Row Count 7 (+ 2)
% Row 3
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{{\bf{Debugging}}:  Inspect data, test methods, or debug application logic.} \tn 
% Row Count 9 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{dependent destroy}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Used in associations specifies when record is deleted, all records are also deleted.} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{* Used in one-many or many-many} \tn 
% Row Count 3 (+ 1)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Ex: Post have comments, if post deleted comment also deleted} \tn 
% Row Count 5 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Callbacks}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{Callbacks are methods that get triggered at certain points in the lifecycle of an object (like before saving, after updating, etc.).} \tn 
% Row Count 3 (+ 3)
% Row 1
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{Common callbacks include: \{\{nl\}\}{\bf{before\_save}}: Runs before a record is saved (on both create and update). Often used for tasks like formatting data.} \tn 
% Row Count 6 (+ 3)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{{\bf{after\_save}}: Runs after a record is saved. Useful for tasks like logging or sending notifications.} \tn 
% Row Count 9 (+ 3)
% Row 3
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{{\bf{before\_validation}}: Runs before validation. Can be used to modify attributes before validation checks.} \tn 
% Row Count 12 (+ 3)
% Row 4
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{{\bf{after\_create}}: Runs after a new record is created., not on updates. Often used to trigger actions like sending welcome emails.} \tn 
% Row Count 15 (+ 3)
% Row 5
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{They are used to execute code at specific points to maintain data consistency or add additional logic.} \tn 
% Row Count 18 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{render vs redirect\_to}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{render}}: It view template without making a new request(redirecting to browser). Simply display view..} \tn 
% Row Count 3 (+ 3)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{{\bf{redirect\_to}}: Redirect browser to another action/ URL, triggering new request.} \tn 
% Row Count 5 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{find vs find\_by vs where}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{Find}}: It looks up a record using its primary key(id). It gives error if records isn't found.} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{{\bf{find\_by}}: Searches for first record that matches certain condition, return nil if no match found.} \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{where}}: Finds all records that meet specific condition \& returns them as list of objects.} \tn 
% Row Count 6 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{resource vs resources}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{resource}}: It will give routes to all command operations except Index.} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{{\bf{resources}}: It will give routes to all command operations} \tn 
% Row Count 4 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{validate vs validates}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{validate }}: It is used to define custom validations method.} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{{\bf{validates }}: It is used to apply built-in validation rules to model attributes.} \tn 
% Row Count 4 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{delete vs destroy}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{delete}}: Doesnot execute callbacks.} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{{\bf{destroy}}: executes callbacks} \tn 
% Row Count 2 (+ 1)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Purpose of rails db:seed task}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{The rails db:seed task is used to populate the database with initial data.} \tn 
% Row Count 2 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{MVC In general}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{MVC is a design pattern used across different programming languages, not just in Ruby. It divides code into Model, View, and Controller layers, which helps organize code by separating data handling, display, and logic, making it easier to develop and maintain applications.} \tn 
% Row Count 6 (+ 6)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Active Record in rails}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Active Record is part of the M in MVC pattern — which is the layer of the system responsible for representing data and business logic.} \tn 
% Row Count 3 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}


% That's all folks
\end{multicols*}

\end{document}