In Angular, directives are classes that add behavior to elements in the DOM. There are two main types: Structural Directives – change the DOM structure (add/remove elements). Examples: *ngIf, *ngFor. Attribute Directives – change the appearance or behavior of an element. Examples: [ngClass], [ngStyle]. 1. Structural Directives *ngIf Conditionally renders elements. <p *ngIf="isLoggedIn"> Welcome,…
In Angular, a decorator is a special kind of declaration that attaches metadata to a class, method, property, or parameter. Angular uses decorators extensively to understand how different pieces of your application should work. They are just functions prefixed with @ that tell Angular how to treat a class or element. Common Angular Decorators…
In Angular, a component is the fundamental building block of the user interface (UI). Structure of a Component A component is made up of three main parts: TypeScript class – contains properties (data) and methods (logic). HTML template – defines what gets rendered on the page. CSS/SCSS styles – optional styles for that component’s…
In Angular, a module is a way to organize an application into cohesive blocks of functionality. 👉 Technically, a module in Angular is defined using the @NgModule decorator.It tells Angular how to compile and launch your application. Key Points about Angular Modules: Root Module (AppModule) Every Angular app has at least one module, called…
In Angular, a project typically follows a well-defined structure that is generated when you run ng new my-appng new my-app Here’s the standard Angular project structure and what each part does: Root Level my-app/ ├── node_modules/ # Installed npm dependencies ├── src/ # Application source code ├── angular.json # Angular workspace configuration ├── package.json…
The Angular CLI (Command Line Interface) is a tool to initialize, develop, scaffold, and maintain Angular applications. 🔹 Installation npm install -g @angular/cli npm install -g @angular/cli Check version: ng version ng version 🔹 Common Angular CLI Commands 1. Create a new Angular project ng new my-appng new my-app 👉 Creates a new project…
In SQL, aggregate functions are functions that perform a calculation on a set of values and return a single value. They’re commonly used with the GROUP BY clause to summarize data. Common Aggregate Functions COUNT() – Counts the number of rows SUM() – Returns the total sum of a numeric column AVG() – Returns…
🔹 Sorting (ORDER BY) You use ORDER BY to arrange query results: SELECT column1, column2 FROM table_name ORDER BY column1 ASC; -- ascending (default) SELECT column1, column2 FROM table_name ORDER BY column1 ASC; -- ascending (default) SELECT column1, column2 FROM table_name ORDER BY column1 DESC; -- descending SELECT column1, column2 FROM table_name ORDER BY…
Querying data in SQL usually means retrieving information from a database using the SELECT statement. Let me give you a structured overview with examples: 🔹 Basic Query SELECT column1, column2 FROM table_name; SELECT column1, column2 FROM table_name; SELECT → specifies the columns you want FROM → specifies the table Example: SELECT first_name, last_name FROM…
Filtering data in SQL is done mainly with the WHERE clause (and sometimes HAVING for aggregated results). It allows you to extract only the rows that meet certain conditions. Here’s a breakdown of the most common filtering techniques: 🔹 1. Basic Filtering with WHERE SELECT * FROM employees WHERE department = 'Sales'; SELECT *…