Team Engine Ruby on Rails Developer Interview Questions and Answers

Meta programming is writing code that can modify or generate other code during runtime.

• Meta programming allows for dynamic code generation and modification at runtime.

• Common examples include defining methods or classes dynamically, modifying existing classes or objects, and creating DSLs.

• Metaprogramming is often used in frameworks like Ruby on Rails to provide powerful abstractions and flexibility.

include is used to add instance methods to a class, while extend is used to add class methods to a class.

• include is used to mix in module methods as instance methods in a class.

• extend is used to mix in module methods as class methods in a class.

• Example: include ModuleName adds ModuleName's instance methods to the class, while extend ModuleName adds ModuleName's class methods to the class.

Monkey patching is the practice of modifying or adding methods to existing classes or modules at runtime.

• Monkey patching can be used to add functionality to third-party libraries without modifying their source code.

• It can lead to unexpected behavior and conflicts if not done carefully.

• Example: Adding a custom method to the String class in Ruby.

Optimizing the database involves indexing, query optimization, denormalization, and caching.

• Use indexing on frequently queried columns to improve search performance.

• Optimize queries by avoiding unnecessary joins and using efficient SQL queries.

• Consider denormalizing data to reduce the number of joins needed for queries.

• Implement caching mechanisms to store frequently accessed data in memory for faster retrieval.

Concerns in Ruby on Rails are used to group common functionality that can be shared across multiple models.

• Concerns help in keeping the code DRY (Don't Repeat Yourself) by extracting reusable code into separate modules.

• They are used to encapsulate shared methods, scopes, validations, callbacks, etc.

• Concerns are included in models using mixins, which allow the shared functionality to be easily added to multiple classes.

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