Violin Technologies Interview Questions and Answers

Left join and left outer join are the same thing.

• Both return all records from the left table and matching records from the right table.

• The only difference is in the case of no matching records in the right table.

• Left join returns null values for the right table columns while left outer join returns all columns with null values for non-matching records.

Distributed architecture is a system where components are spread across multiple computers. Disconnected architecture is a system where components can operate independently without a constant connection.

• Distributed architecture involves multiple computers working together to achieve a common goal.

• Disconnected architecture allows components to operate independently without a constant connection to a central system.

• Distributed architecture can improve scalability and fault tole...read more

Stateless refers to a system that does not store any data or information about previous interactions. State management is the process of managing and maintaining the state of a system.

• Stateless systems do not rely on previous interactions or data to function

• State management involves keeping track of the current state of a system

• State can be managed through various techniques such as cookies, sessions, and local storage

• Examples of stateless systems include RESTful APIs and HTT...read more

Indexes can slow down write operations and take up additional storage space.

• Indexes can slow down write operations because every time data is added, updated, or deleted, the index must also be updated.

• Indexes can take up additional storage space because they are essentially a copy of the data in the table, just sorted differently.

• Indexes can also become fragmented over time, which can lead to decreased performance.

• Indexes are not always useful for small tables or tables that ...read more

Sessions are a way to maintain state between HTTP requests. Caching is a technique to store frequently accessed data in memory.

• Sessions are used to store user-specific data across multiple requests

• Caching is used to improve performance by storing frequently accessed data in memory

• Sessions can be implemented using cookies or server-side storage

• Caching can be implemented using in-memory caches or distributed caches like Redis

• Examples of data that can be cached include database ...read more

Observable and subscribe are two important concepts in reactive programming.

• Observable is a stream of data that emits values over time.

• Subscribe is a method that listens to the emitted values from an observable.

• Observable can be created from various sources like events, promises, arrays, etc.

• Subscribe can have three callbacks - next, error, and complete.

• Next callback is called when a new value is emitted, error callback is called when an error occurs, and complete callback is...read more