What is the purpose of a database lock in concurrency control?
- Ensure Data Consistency
- Manage Concurrent Access
- Optimize Query Performance
- Prevent Unauthorized Access
The purpose of a database lock in concurrency control is to manage concurrent access to ensure data consistency. Locks are mechanisms used to control access to a shared resource, preventing conflicts that may arise when multiple transactions try to access or modify the same data simultaneously.
What is encapsulation in OOP?
- Binding data and methods that manipulate it
- Implementing interfaces
- Inheriting properties from a superclass
- Overriding methods in a subclass
Encapsulation in Object-Oriented Programming (OOP) involves binding data and the methods that manipulate it together. It helps in hiding the internal details of an object and exposing only what is necessary.
In a project, you need to create a navigation menu that changes its appearance on hover. Which CSS feature would you utilize for this effect?
- :hover pseudo-class
- Animation
- Flexbox
- Transition
The :hover pseudo-class in CSS is used to apply styles when an element is being hovered. It's commonly used for creating interactive effects like changing the appearance of a navigation menu on hover.
In logging, what does the term "log rotation" refer to?
- Creating new log entries
- Encrypting log data
- Filtering logs based on severity
- Managing log files by limiting size or age
Log rotation in logging refers to managing log files by limiting their size or age. It involves the process of archiving or deleting old log files to prevent them from consuming excessive disk space and to ensure efficient log file management.
Explain the difference between pessimistic and optimistic concurrency control.
- Optimistic concurrency assumes conflicts are rare and allows transactions without locking, checking conflicts later.
- Optimistic concurrency is less scalable than pessimistic concurrency.
- Pessimistic concurrency allows only one transaction at a time.
- Pessimistic concurrency assumes conflicts and locks data during transactions.
Pessimistic concurrency control assumes conflicts may occur, so it locks data during transactions. In contrast, optimistic concurrency control assumes conflicts are rare and allows transactions without locking, checking for conflicts later in the process.
What does the "integration" part of Continuous Integration refer to?
- Continuous Code Integration
- Continuous Collaboration
- Continuous Deployment
- Continuous Testing
In Continuous Integration, the "integration" refers to continuously integrating code changes from multiple contributors into a shared repository. This ensures that the codebase is regularly updated and tested as a whole.
Explain how Blue-Green Deployment works in a CI/CD pipeline and its advantages over traditional deployment methods.
- Parallel Deployment of Versions, Traffic Switching, Separate Environments, Rollback Capabilities
- Sequential Deployment of Versions, Load Balancing, Canary Testing, A/B Testing
- Simultaneous Deployment of New and Old Versions, Traffic Routing, Quick Rollback
- Staged Deployment of Versions, Manual Switching, Automated Testing, Incremental Rollout
Blue-Green Deployment involves having two identical environments, one serving production (Blue) and the other for deployment (Green). Traffic is switched between them, allowing quick rollback and reduced downtime. Advantages include minimal downtime and the ability to test new releases in a production-like environment.
What is the purpose of the "Network" tab in Browser Developer Tools?
- Analyze CSS styles
- Debug JavaScript code
- Inspect HTML elements
- Monitor network activity
The "Network" tab in Browser Developer Tools is used to monitor network activity. It provides insights into the requests and responses made by the browser, helping developers optimize page loading performance.
Which of the following tools is commonly used for logging in web applications?
- Bootstrap
- Git
- Log4j
- jQuery
Log4j is commonly used for logging in web applications. It is a Java-based logging utility that allows developers to generate log statements from their code, helping in debugging, troubleshooting, and monitoring the application's behavior.