What is alias in rails?
To alias a method or variable name in Ruby is to create a second name for the method or variable. Aliasing can be used either to provide more expressive options to the programmer using the class or to help override methods and change the behavior of the class or object.
What is ActiveRecord?
Active Record allows you to validate the state of a model before it gets written into the database. There are several methods that you can use to check your models and validate that an attribute value is not empty, is unique and not already in the database, follows a specific format, and many more.
What does ActiveRecord base do?
ActiveRecord::Base indicates that the ActiveRecord class or module has a static inner class called Base that you’re extending.
What is Ruby ActiveRecord?
What is ActiveRecord? ActiveRecord is an ORM. It’s a layer of Ruby code that runs between your database and your logic code. When you need to make changes to the database, you’ll write Ruby code, and then run “migrations” which makes the actual changes to the database.
What is Define_method in Ruby?
define_method is a method defined in Module class which you can use to create methods dynamically. To use define_method , you call it with the name of the new method and a block where the parameters of the block become the parameters of the new method.
What is undef in Ruby?
Ruby provides a special keyword which is known as undef keyword. This keyword used to avoid the current working class from responding to calls to the specified named methods or variable. Or in other words, once you use under keyword with any method name you are not able to call that method.
Is ActiveRecord an anti pattern?
In software engineering, the active record pattern is considered an architectural pattern by some people and as an anti-pattern by some others recently. It is found in software that stores in-memory object data in relational databases.
Is ActiveRecord a good pattern?
About suitability of the pattern Martin Fowler says: “Active Record is a good choice for domain logic that isn’t too complex, such as creates, reads, updates, and deletes. Derivations and validations based on a single record work well in this structure.”
Can you use ActiveRecord without Rails?
One of the primary aspects of ActiveRecord is that there is very little to no configuration needed. It follow convention over configuration. ActiveRecord is commonly used with the Ruby-on-Rails framework but you can use it with Sinatra or without any web framework if desired.
What are models in ROR?
What are models? In simple terms, models are Ruby classes that can holds value of a single row in a database table. Since they all inherit ActiveRecord::Base through ApplicationRecord class, they are equipped with all the ActiveRecord methods which enables them to interact with the database.
Is ActiveRecord part of Rails?
Rails Active Records provide an interface and binding between the tables in a relational database and the Ruby program code that manipulates database records. Ruby method names are automatically generated from the field names of database tables.
What is metaprogramming in Ruby on Rails?
Metaprogramming is a technique by which you can write code that writes code by itself dynamically at runtime. This means you can define methods and classes during runtime.
What is Instance_variable_get in Ruby?
instance_variable_get is a method defined on Object that works much the same way as const_get . It allows you to retrieve the value of an instance variable defined on your class or module. Example Code: class Monk def initialize @zen = 42 end end p Monk.new.instance_variable_get(“@zen”)
What is puppet undef?
Puppet’s undef value is roughly equivalent to nil in Ruby. It represents the absence of a value.
How do I check if a variable is defined in Ruby?
How to Check If a Variable is Defined in Ruby
- If the variable exists you’ll get its type: apple = 1 defined?(apple) # “local-variable”
- If it doesn’t you’ll get nil: defined?(bacon) # nil.
- For local variables: local_variables.include?(:orange)
- For instance variables: instance_variable_defined?(“@food”)
What are inactive records?
Inactive records are documents (both hardcopy and electronic) which are no longer referenced on a regular basis and tend to be stored in a less accessible place since they are not used frequently. Many times records become inactive when they reach their cut-off as defined on a Records Retention Schedule.
What is PHP Active Record pattern?
The Active Record pattern effectively prescribes to wrap a row of a database table in a domain object with a 1:1 relationship, managing its state and adding business logic in the wrapping class code.
What is inactive record?
How you can run Rails application without creating databases?
For Rails 3 and Rails 4: Use -O (Capital ‘O’) or –skip-activerecord option to generate an application without a database. Notice the extra hyphen ‘-‘ as opposed to previous Rails versions.
What is Sinatra ActiveRecord?
Sinatra ActiveRecord Extension
Extends Sinatra with extension methods and Rake tasks for dealing with an SQL database using the ActiveRecord ORM.
How do you make a ROR model?
Generating a model in Rails – YouTube
What is difference between new and create in Rails?
New instantiates a new Model instance, but it is not saved until the save method is called. Create does the same as new, but also saves it to the database. Sometimes you want to do stuff before saving something to the database, sometimes you just want to create and save it straight away.
What is ActiveRecord implementation?
The active record pattern is an approach to accessing data in a database. A database table or view is wrapped into a class. Thus, an object instance is tied to a single row in the table. After creation of an object, a new row is added to the table upon save. Any object loaded gets its information from the database.
What is monkey patching in Ruby?
In Ruby, a Monkey Patch (MP) is referred to as a dynamic modification to a class and by a dynamic modification to a class means to add new or overwrite existing methods at runtime. This ability is provided by ruby to give more flexibility to the coders.
Is monkey patching metaprogramming?
Monkey patching is the first step towards meta-programming – writing code which writes code.