Php Lead Interview Questions and Answers

Interface defines only method signatures while abstract class can have both method signatures and implementations.

• Interface cannot have method implementations, only method signatures.

• Abstract class can have both method signatures and implementations.

• A class can implement multiple interfaces but can only inherit from one abstract class.

• Interfaces are used to define a contract for classes to implement, while abstract classes are used to provide a common base for subclasses.

InnoDB is a transaction-safe storage engine for MySQL, while MyISAM is not transaction-safe.

• InnoDB supports transactions with ACID properties, while MyISAM does not.

• InnoDB supports foreign keys, while MyISAM does not.

• InnoDB is more reliable and crash-safe compared to MyISAM.

• InnoDB is the default storage engine for MySQL 5.5 and higher versions.

• MyISAM is faster for read-heavy operations, while InnoDB is better for write-heavy operations.

A callback function in PHP is a function that is passed as an argument to another function and is executed at a later time.

• Callback functions are commonly used in PHP for event handling, asynchronous processing, and custom sorting.

• Example: array_map() function in PHP takes a callback function as an argument to apply a user-defined function to each element of an array.

• Another example: usort() function in PHP uses a callback function to define custom sorting logic for an array.

MVC is a software design pattern that separates an application into three main components: Model, View, and Controller.

• Model represents the data and business logic of the application.

• View is responsible for displaying the data to the user.

• Controller acts as an intermediary between Model and View, handling user input and updating the Model accordingly.

• MVC helps in organizing code, improving maintainability, and promoting code reusability.

• Popular PHP frameworks like Laravel and...read more

A static method is a method that belongs to the class itself, rather than to instances of the class.

• Static methods can be called directly on the class without needing to create an instance of the class.

• Static methods are commonly used for utility functions that do not require access to instance-specific data.

• Static methods are declared using the 'static' keyword in PHP.

Optimizing SQL queries involves analyzing query performance, indexing, minimizing data retrieval, and using appropriate joins.

• Analyze query performance using tools like EXPLAIN to identify bottlenecks

• Use indexes on columns frequently used in WHERE clauses

• Minimize data retrieval by selecting only necessary columns

• Avoid using SELECT * and instead specify required columns

• Use appropriate joins like INNER JOIN, LEFT JOIN, etc. based on data relationships

PHPUnit workflow involves writing test cases, running tests, and analyzing results.

• Write test cases using PHPUnit framework

• Run tests using PHPUnit command line interface or IDE integration

• Analyze test results to identify failures and errors

• Make necessary code changes to fix failing tests

• Repeat the process until all tests pass successfully