How to query data in laravel? Introduction to common methods

Laravel is a popular PHP framework used for developing web applications. In developing web applications, querying the database is a very common operation. This article will introduce how to use laravel to query data in the database.

Laravel provides many built-in functions that can easily query the database. Its query builder allows you to write SQL queries using an object-oriented approach. It also provides Eloquent ORM, a simple yet powerful ORM for managing database records.

The following are some commonly used laravel query methods:

Basic query

The most basic laravel query uses the DB class. The DB class provides many methods that allow you to easily perform SQL queries. Here is an example of querying all users using the DB class:

$users = DB::select('SELECT * FROM users');

This code will execute a simple SQL query and store the results in the $users variable. You can also pass the parameters in the query to the select function:

$users = DB::select('SELECT * FROM users WHERE active = ?', [1]);

This will query all users whose "active" field is 1.

Query Builder

The query builder is one of laravel's core query mechanisms. Query builder lets you build SQL queries using an object-oriented approach. Here is an example of querying all users using the query builder:

$users = DB::table('users')->get();

This code will retrieve all records from the "users" table and store the results in the $users variable.

You can also use the select method in the query builder to specify the columns to retrieve:

$users = DB::table('users')->select('name', 'email')->get();

This will retrieve "name" and "name" from the "users" table "email" column.

Eloquent ORM

Eloquent ORM is another query mechanism for laravel. It provides a very simple yet powerful way to manage database records. Eloquent ORM uses models to represent data in database tables. Here is an example of querying all users using Eloquent ORM:

$users = App\User::all();

This code will retrieve all records from the "users" table and store the results in the $users variable. You can also chain call other functions to filter the results:

$users = App\User::where('active', 1)->get();

This will query all users whose "active" field is 1.

Summary

Laravel provides developers with many powerful mechanisms to query the database. Whether you want basic SQL queries or query your data using an object-oriented approach, laravel has a solution. Choose the way that works best for you and start building amazing web applications!

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