A Foreign Key is a column in one table that is used to connect it with another table. Think of it like a relationship: So: Rules of Foreign Key Example in MySQL Table 1: students Data: student_id name 1 Ramesh 2 Priya Table 2: marks Here: Insert Data sqlINSERT INTO marks VALUES (1, 1, ‘Maths’, … Read more
A Primary Key is a column (or set of columns) in a table that uniquely identifies each row. Think of it like your Aadhar Number or Roll Number in college: That’s exactly how a primary key works in SQL. Rules of Primary Key Example in MySQLTable without primary key: Here, nothing stops two students from … Read more
A subquery is a query (SQL statement) inside another query.It’s like asking one question inside another question to get your final answer. Syntax: Example of a Subquery Imagine two tables: students id name class_id 1 Ramesh 101 2 Priya 102 3 Amit 101 classes class_id class_name 101 Science 102 Arts Question: Find students who belong … Read more
Here’s a simple and clear explanation of the difference between WHERE and HAVING in SQL: Quick Explanation Difference Between WHERE and HAVING Feature WHERE HAVING Purpose Filters rows before grouping (used on individual rows) Filters groups after grouping (used with GROUP BY) Used With Any table or query Only with GROUP BY or aggregate functions … Read more
Null-safe operator is a new syntax in PHP 8.0, that provides optional chaining feature to PHP. In PHP, when working with objects, sometimes a property or method may not exist (it can be null).Normally, checking this requires multiple if conditions to avoid errors. PHP 8 introduced the Nullsafe Operator (?->) to make this easy. Old Way (Before … Read more
Constructor Property Promotion is a new syntax in PHP 8 that allows class property declaration and constructor assignment right from the constructor. In PHP (before version 8), when we created a class, we had to: This meant writing a lot of repeated code. Old Way (Before PHP 8) Here we are writing $name and $age two times: New Way … Read more
The match expression, introduced in PHP 8.0, offers a modern way to handle multiple conditional checks. The new match expression in PHP 8 is a control flow structure that matches a given subject expression with one or more alternative conditional expressions using identity comparison and returns a value from the matched branch. Match expression syntax … Read more
PHP, and many other programming languages, support positional parameters: The caller passes the parameters in the same order the function/method declares its parameters. In PHP 8.0, Named Parameters support is added, which means it’s now possible to call a function/method by setting the parameters by their name. Named Arguments (introduced in PHP 8) let you … Read more
Union types are one of the most exciting new features in PHP 8. Its accepts values of multiple different data types, rather than a single one. Union Types allow a function, method, or property to accept multiple different types for a parameter, return value, or property. Before PHP 8, you usually had to rely on PHPDoc annotations … Read more
JIT (Just-In-Time) compilation is a technique where code is converted into machine language at runtime instead of being purely interpreted or precompiled. In PHP, this means the Zend Engine (PHP’s core runtime) can translate PHP opcodes (intermediate code) into native machine code just before execution. As a result, PHP can run certain workloads much faster, … Read more