Eager loading (with) in Laravel - Step-by-Step Execution

Concept Flow - Eager loading (with)

Start Query

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Specify Relations with with()

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Build SQL for Main Model

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Build SQL for Related Models

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Execute Queries

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Combine Results

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Return Models with Relations Loaded

This flow shows how Laravel builds and executes queries to load main models and their related models together using eager loading.

Execution Sample

Laravel

User::with('posts')->get();

This code loads all users and their related posts in one go to avoid extra queries later.

Execution Table

Step	Action	Query Built	Result	Notes
1	Start query for User model	SELECT * FROM users	All users fetched	Main model query prepared
2	Identify relation 'posts'	SELECT * FROM posts WHERE user_id IN (user ids)	Posts for all users fetched	Related model query prepared
3	Combine users and posts	N/A	Users with posts attached	Eager loading combines data
4	Return result	N/A	Collection of users with posts	Ready for use without extra queries
5	End	N/A	Query complete	No lazy loading needed

💡 All related posts loaded with users, avoiding multiple queries per user.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
users	empty	all users from DB	all users from DB	users with posts attached	users with posts attached
posts	empty	empty	all posts for users	all posts for users	all posts for users

Key Moments - 2 Insights

Why does Laravel run two queries instead of one when using with('posts')?

Laravel runs one query for users and one for posts with a WHERE IN clause to efficiently load all related posts at once, as shown in execution_table rows 1 and 2.

What happens if we don't use with() and access posts later?

Without with(), Laravel runs a new query for posts each time you access posts on a user, causing many queries. Eager loading avoids this by loading all posts upfront (see execution_table row 5).

Visual Quiz - 3 Questions

Look at the execution table, what query is built at step 2?

A SELECT * FROM users

B SELECT * FROM posts

C SELECT * FROM posts WHERE user_id IN (user ids)

D SELECT * FROM users WHERE id IN (post ids)

💡 Hint

Check the 'Query Built' column in row 2 of the execution_table.

At which step are users combined with their posts?

A Step 3

B Step 2

C Step 1

D Step 4

💡 Hint

Look at the 'Action' column describing combining results in the execution_table.

If we remove with('posts'), how would the variable 'posts' change after step 2?

A It would contain all posts for users

B It would remain empty

C It would contain posts for only one user

D It would cause an error

💡 Hint

Refer to variable_tracker row for 'posts' and understand eager loading effect.

Concept Snapshot

Eager loading with with() loads related models in advance.
Syntax: Model::with('relation')->get();
Runs separate queries for main and related models.
Combines results to avoid many queries later.
Improves performance by reducing database calls.

Full Transcript

Eager loading in Laravel uses the with() method to load related models together with the main model. When you call User::with('posts')->get(), Laravel builds one query to get all users and another query to get all posts for those users using a WHERE IN clause. Then it combines the posts with their respective users before returning the result. This avoids running a new query for posts each time you access them on a user, which would happen without eager loading. The process involves starting the main query, preparing the related query, executing both, and combining the data. This makes your app faster and more efficient by reducing the number of database queries.