Ruby Developer

Class libraries in Ruby consist of a variety of domains, such as data types, thread programming, various domains, etc.

Yes, with the help of the send method.

Given the class Test:

class Test

private

def method

p "I am a private method"

end

end

We can execute the private method using send:

>> Test.new.send(:method)

"I am a private method"

ORM stands for Object Relationship Model that models the classes and helps in setting a relationship between the existing models.

Functions:

1. It allows the classes to be mapped to the table that is present in the database and objects get mapped to the rows in database table.

2. It shows the relationship that exists between the object and frame it using the model to display the output to the users.

3. It keeps the data in the database according to its relationships and performs the functions accordingly.

Modules are Ruby’s way of grouping methods, classes, and constants together to provide a namespace for preventing name clashes. The second purpose of modules is to use them as mixins. Technically, Ruby only supports single inheritance, but by using modules as mixins, it is possible to share code among different classes—a key advantage of multiple inheritance—without having to give up the simplicity of the single inheritance paradigm.

The “include” makes the module’s methods available to the instance of a class, while “extend” makes these methods available to the class itself.

The syntax for Ruby collect Iterator collection = collection.collect.

Unlike the puts statement, which outputs the entire string onto the screen. The Putc statement can be used to output one character at a time.

Ruby regular expression is a special sequence of characters that helps you match or find other strings. A regular expression literal is a pattern between arbitrary delimiters or slashes followed by %r.

Dynamic Scaffolding:

It automatically creates the entire content and user interface at runtime

It enables to generation of new, delete, edit methods for the use in application

It does not need a database to be synchronized

Static Scaffolding:

It requires manual entry in the command to create the data with their fields

It does not require any such generation to take place

It requires the database to be migrated

Rake is a Ruby Make; it is a Ruby utility that substitutes the Unix utility ‘make’, and uses a ‘Rakefile’ and ‘.rake files’ to build up a list of tasks. In Rails, Rake is used for normal administration tasks like migrating the database through scripts, loading a schema into the database, etc.

The Hash class in Ruby’s core library returns value by using a standard “= =” comparison on the keys. It means that the value stored for a symbol key cannot be retrieved using the equivalent string. While the HashWithIndifferentAccess treats Symbol keys and String keys as equivalent.

Rails Migration can do following things

☛ Create table

☛ Drop table

☛ Rename table

☛ Add column

☛ Rename column

☛ Change column

☛ Remove column and so on

Symbol is different from variables in following aspects

☛ It is more like a string than variable

☛ In Ruby string is mutable but a Symbol is immutable

☛ Only one copy of the symbol requires to be created

☛ Symbols are often used as the corresponding to enums in Ruby

In Ruby False indicates a Boolean datatype, while Nil is not a data type, it have an object_id 4.

Ruby: It is an object oriented programming language inspired by PERL and PYTHON.

Rails: It is a framework used for building web application

☛ App/controllers: A web request from the user is handled by the Controller. The controller sub-directory is where Rails looks to find controller classes

☛ App/helpers: The helper’s sub-directory holds any helper classes used to assist the view, model and controller classes.

To create migration command includes

C:rubyapplication>ruby script/generate migration table_name

You can execute your application by uncommenting the line in environment.rb

path=> rootpath conf/environment.rb

config.frameworks = [ action_web_service, :action_mailer, :active_record]

☛ super(): A call to super() invokes the parent method without any arguments, as presumably expected. As always, being explicit in your code is a good thing.

☛ super call: A call to super invokes the parent method with the same arguments that were passed to the child method. An error will therefore occur if the arguments passed to the child method don’t match what the parent is expecting.

In Ruby,

☛ A constant should begin with an uppercase letter, and it should not be defined inside a method

☛ A local must begin with the _ underscore sign or a lowercase letter

☛ A global variable should begin with the $ sign. An uninitialized global has the value of “nil” and it should raise a warning. It can be referred anywhere in the program.

☛ A class variable should begin with double @@ and have to be first initialized before being used in a method definition