Data access in Laravel.
WHAT THE ORM PROVIDES
Models mapping to tables, with relationships expressed in code.
WHAT RELATIONSHIPS EXIST
One to one, one to many, many to many, and polymorphic variants.
WHAT THE COMMONEST PERFORMANCE FAULT IS
Querying inside a loop, producing one query per record.
WHAT CAUSES IT
Accessing a relationship on each item of a collection.
WHAT SOLVES IT
Loading relationships in advance, in one query.
WHAT TO DO
Establish which relationships a view uses, and load them with the collection.
WHAT TO MONITOR
Query count per request, during development.
WHY
It reveals the fault immediately, and nothing else does.
WHAT MIGRATIONS PROVIDE
Schema changes as versioned code, applied consistently.
WHAT TO ALWAYS WRITE
A way to reverse each migration.
WHAT TO BE CAREFUL WITH
Migrations that cannot be reversed Migrations altering large tables without considering locking Mass assignment, without restricting which fields are fillable
WHY THAT LAST ONE
It allows a request to set fields it should not.
WHAT TO USE FOR MONEY
Exact decimal types, never floating point.
