PHP Schema Engine

A modern schema-first migration engine for PHP.

PHP Schema Engine lets you define your database structure using a clean PHP DSL, compare it against the current database schema, generate SQL automatically, and apply changes through a lightweight CLI.

Current version: 0.3.0-alpha

---

Features

• Schema-first database definition
• Fluent PHP DSL
• MySQL/MariaDB support
• Automatic schema introspection
• Table and column diffing
• Partial index diffing
• SQL generation
• Migration execution
• Migration history
• Model generation
• Dry-run mode
• Destructive operation protection
• Database reset support
• Snapshot generation
• Foreign key support
• Debug trace mode

---

Installation

composer require erilshackle/php-schema-engine

For local development:

composer install

---

Initialization

Generate the default configuration file:

php bin/migrate --init

This creates:

schema-engine.php

---

Configuration

Generated config example:

<?php

return [

    // Schema file path
    'schema' => '/database/schema.php',

    // Database connection configuration
    'database' => [
        'driver' => 'mysql',
        'host' => $_ENV['DB_HOST'] ?? '127.0.0.1',
        'port' => $_ENV['DB_PORT'] ?? 3306,
        'database' => $_ENV['DB_NAME'] ?? 'app',
        'username' => $_ENV['DB_USER'] ?? 'root',
        'password' => $_ENV['DB_PASS'] ?? '',
    ],

    // Model generator setup
    'generator' => [
        'models' => [
            'enabled' => false,
            'namespace' => 'App\\Models',
            'path' => '/app/Models',
            'extends' => null,
        ],
    ],
];

Optional bootstrap file:

bootstrap.php

Useful for:

• loading .env
• bootstrapping frameworks
• loading helpers
• custom runtime setup

---

Basic Usage

Create a schema file:

<?php

use SchemaEngine\DSL\Schema;
use SchemaEngine\DSL\Table;

return function (Schema $schema) {

    $schema->table('users', function (Table $t) {

        $t->id();

        $t->string('name');

        $t->string('email')
            ->unique();

        $t->timestamps();
    });

};

Run a dry-run first:

php bin/migrate --dry-run

Apply the migration:

php bin/migrate --yes

---

Defining Tables

$schema->table('users', function ($t) {

    $t->id();

    $t->string('name');

    $t->string('email')
        ->unique();

    $t->int('age')
        ->default(0);

    $t->timestamps();
});

---

Column Types

$t->id();

$t->string('name');

$t->char('code', 2);

$t->text('body');

$t->longText('content');

$t->int('age');

$t->bigInt('views');

$t->float('rating');

$t->double('score');

$t->decimal('price', 10, 2);

$t->boolean('active');

$t->datetime('published_at');

$t->timestamp('created_at');

$t->json('meta');

$t->uuid('uuid');

---

Column Modifiers

$t->string('email')
    ->unique();

$t->string('slug')
    ->index();

$t->string('name')
    ->nullable();

$t->int('age')
    ->default(0);

$t->timestamp('created_at')
    ->defaultCurrentTimestamp();

$t->timestamp('updated_at')
    ->defaultRaw('CURRENT_TIMESTAMP');

---

Shortcuts

$t->id();

$t->timestamps();

$t->createdAt();

$t->updatedAt();

$t->softDeletes();

$t->rememberToken();

---

Indexes

Single-column indexes:

$t->string('email')
    ->unique();

$t->string('slug')
    ->index();

Composite indexes:

$t->unique(['email', 'tenant_id']);

$t->index(['first_name', 'last_name']);

Indexes are automatically introspected and partially diffed.

Current V1 behavior:

• missing indexes are automatically added
• removed indexes are automatically dropped
• changed indexes are ignored intentionally with warnings

Example warning:

Index 'email_unique' on table 'users' differs from desired schema and was ignored.

---

Foreign Keys

Simple inferred relation:

$t->foreignId('user_id');

Explicit references:

$t->foreignId('user_id')
    ->constrained() // or references('users')
    ->cascadeOnDelete();

Custom table:

$t->foreignId('author_id')
    ->references('users');

Custom referenced column:

$t->uuid('author_id')
    ->references('users', 'uuid');

Available relation actions:

->cascadeOnDelete()

->cascadeOnUpdate()

->restrictOnDelete()

->restrictOnUpdate()

->nullOnDelete()

->nullOnUpdate()

In V1, foreign keys are generated when creating new tables only. Foreign key changes after table creation are not automatically migrated yet.

---

Model Generation

Generate models from your schema:

php bin/migrate --generate-models

Example generated model:

<?php

namespace App\Models;

class User
{
    protected string $table = 'users';
}

Generator configuration:

'generator' => [
    'models' => [
        'enabled' => true,
        'namespace' => 'App\\Models',
        'path' => '/app/Models',
        'extends' => 'App\\Core\\Model',
    ],
],

---

CLI

Dry-run:

php bin/migrate --dry-run

Apply migrations without confirmation:

php bin/migrate --yes

Allow destructive operations:

php bin/migrate --force

Show migration history:

php bin/migrate --status

Reset database:

php bin/migrate --fresh --force --yes

Reset database and clear history:

php bin/migrate --fresh --force --yes --clear-history

Generate models:

php bin/migrate --generate-models

Show stack trace on exceptions:

php bin/migrate --trace

---

Migration History

Executed operations are stored in:

schema_migrations

This table is managed internally by the engine and ignored during schema diffing.

---

Safety

By default, destructive operations are blocked.

This includes:

• dropping tables
• dropping columns
• dropping indexes

To allow destructive operations:

php bin/migrate --force

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Debugging

Enable stack traces during execution:

php bin/migrate --trace

Example output:

[ERROR] Table users already exists
File: .../Migrator.php:62

Stack trace:

#0 .../Migrator.php:62 run()
#1 .../MigrateCommand.php:88 printPlannedSql()
#2 .../bin/migrate:24 run()

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Current Limitations

PHP Schema Engine 0.1.0-alpha is intentionally conservative.

Current V1 limitations:

• MySQL/MariaDB only
• Index diffing is partial and intentionally conservative
• Existing indexes are not automatically modified
• Foreign key changes after table creation are not automatically migrated
• Rename detection is disabled by default
• Table recreation is not implemented yet
• No PostgreSQL grammar yet
• No SQLite grammar yet
• No ORM/query builder layer yet

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Philosophy

PHP Schema Engine follows a schema-first approach.

The schema file is the source of truth.

Schema DSL
    ↓
Schema Metadata
    ↓
Database Introspection
    ↓
Diff Engine
    ↓
SQL Generation
    ↓
Migration Execution

The DSL is designed to stay expressive, while the internal architecture keeps metadata, diffing, SQL generation, and execution separated.

---

Roadmap

V0.1

• Schema DSL
• MySQL introspection
• Column diffing
• Partial index diffing
• SQL generator
• CLI
• Migration history
• Model generation
• Foreign keys on create

V0.2

• migrate:fresh
• migrate:reset
• better CLI output
• schema snapshots
• explicit rename operations

V0.3

• advanced index diffing
• foreign key diffing
• table recreation mode
• rollback support

V1.0

• stable public API
• stronger type system
• advanced MySQL grammar
• multi-driver foundation

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License

MIT