Chapter 5

Database configuration file:
- configure/database.php

You select a specific connection with:
- DB::connection("secondary")->select("select * from users");

Migration:
- migration is a snigle file to define the modificatoins up and down
- make migration:
    = php artisan make:migration create_name_table
    = optional flag: --table=table_name for modifying 
    = optional flag: --create=table_name for creating

Creating Tables:
- method create(table_name, closure to define columns)
- pass the $table as a Blue print instance, it has the methods

Columns types:
- integer, tinyInteger, smallInteger, mediumInteger, bigInteger
- string
- boolean
- binary: BLOB
- decimal
- double
- float
- char
- datetime
- enum
- json, jsonb
- text
- time
- timestamp
- uuid

Special Columns:
- Increments, bigIncrements
- timestamps: created_at, updated_at
- remeberToken
- softDelete
- morphs

Extra properties:
- nullable
- after
- first
- last
- default
- unique
- primary
- index
- unsigned

Drop:
- dropIfExists("table_name")

Modifying columns:
- same as creating then ->change()
- renameColumn(): to rename
- dropColumn(): to drop

Indexes and foreign keys:
- primary: not necessary with increments
- unique
- index
- dropPrimary, dropUnique and dropIndex to drop indexes
- foreign key: $table->foreign("user_id")->references("id")->on("users)
- you can use onDelete(), onUpdate()
- dropForeign()

Running migrations:
- php artisan migrate: you can use --seed
- migrate:install: create table trackers (runs automatically with migrate)
- migrate:reset: rolls back all the migrations
- migrate:refresh: reset then migrate
- migrate:fresh: like refresh but doesn't run down(), it just deletes the tables
- migrate:rollback: rolls back the nth migration (--step=n)
- migrate:status: shows every migration and Y or N

Seeding:
- --seed to run the seeders with migration
- php artisan db:seed --class=VotesTableSeeder to run independently
- php artisan make:seeder ContactsTableSeeder: to create seeder

Factory models:
- 


Query builder:
- DB::statement("drop table users"): I think it is like exec
- DB::select("select * from table where id = ?", [3])
- DB::table("users")->get()


Transactions:
- A group of commands to be done all, or no one if any one fails.
- DB::transaction(function() use ($userId, $numVotes){
        DB::table() // etc
    }) 
- for manual transactions
- DB::beginTransaction();
    if($error) {
        DB::rollback();
    }
    DB::commit();


== Eloquent ==

Making a model
- php artisan make:model (you can use --migration or -m to make a migration with it)
- for customizing default table props: $table, $primaryKey, $incrementing, $timestamp, $dateFormat(takes format like php date())

Getting data:
- first, find (OrFail)
- uset get() instead of all()

Chunk
- breaking the requests into smaller pieces
- Contact::chunk(100, function($contacts) {
    foreach($contacts as $contact) {
        
    }
})

- Aggregates: count, sum, avg


Insert and update with eloquent:
- Two primary ways:
    = $contact = new Contact() or Contact:make, then $contact->save()
    = Contact::create();
- Updating:
    = $contact = Contact::find(). $contact->save();
    = Contact::where("id", 20)->update(["name] => "Mohamed")
    = $contact = Contact::find(), $contact->update(["name" => "Mohamed"]);

Mass assignment:
- protected $fillable, $guarded
- firstOrCreate(), firstOrNew()

Deleting:
- $contact = Contact::find(4)
    $contact->delete();
- Contact::destroy(4);
- Contact::where()->delete();

Soft deletes:
- Enable it by doing three things:
    = adding deleted_at column: $table->softDelete(), in the migration
    = import the Trait, softDelete
    = $dates = ["deleted_at"] in the Model
- Contact::withTrashed()->get()
- $contact->isTrashed() -> boolean
- Contact::onlyTrashed()->get()
- $contact->restore()
- $contact->forceDelete()


Scopes:
- Local scope: scopeScopeName($query, $property)
    {
        return $query->where("prop", $property);    
    }
- Global scopes: 
    - closure or class
    - delete them with "withoutGlobalScope" or "withoutGlobalScopes(), accepts name or class, the second one accepts array of them and can exclude all when passed an empty array

Accessors:
    - get custom attributes from models
    - getTestAttribute => $model->test

Mutators:
    - to change the value before inserting it to the database column
    - getTestAttribute

Casts:
    - to cast data from databse into some datatypes in laravel (Collection, Carbon...etc)


Collections:
    - Tightanco/Collection package to use collections outside laravel
    - create: collect([...array])
    - reject? to delete some elements upon a condition
    - map? to update all elements with a function
    - sum()? reduce the collection into some number
    - and more than 60 mehthods available on collection
    - they are treated like normal arrays
    - custom collections on models? newCollection($models)


Serialization:
    - toArray()
    - toJson()
    - you can just use simple casting to string and the collection will use toJson()
    - $appends, to add the extra columns to json output
    - hidden, visible for displaying fields into the json response
    - appends
    - 

Relationships:

- One to One:
    - $this->hasOne(AnotherEloquent::class)
    - $this->belongsTo()

- One to Many:
    - $this->hasMany()
    - $this->belongsTo()
    - associate and dissociate
    - Model::has('field') // returns only records that has related "field" 
    - whereHas
    - hasManyThrough
    - hasOneThrough

- Many to Many:
    - pivot table: tabl1_table2 sorted alphapitically
    - belongsToMany: in both models

- Child Updating timestamps
    - touches

- Eager loading
    - with()
    - load()
    - loadMissing()
    - withCount()



Eloquent Events

-