nette-database

Database

Uses Nette Database with MySQL 8.4+ as the backend.

composer require nette/database

For complete Explorer API, see explorer.md. For SQL queries, see sql-way.md.

Database Conventions

• Table names use singular form (e.g., user not users)
• Use TINYINT(1) for booleans
• Use id for primary keys
• Character encoding should be:
  • utf8mb4_cs_0900_ai_ci for Czech-language applications
  • utf8mb4_0900_ai_ci for English-language applications
• Standard timestamp fields:
  • created_at DATETIME DEFAULT CURRENT_TIMESTAMP
  • never use TIMESTAMP for date/time fields

Database Explorer

Extends Nette Database Explorer to automatically map database tables to typed entity classes.

Core benefit: Zero-configuration entity mapping with full IDE support. How it works: Converts table names (snake_case) to entity class names (PascalCase + Row suffix).

Entity Design Strategy

All entities in App\Entity with consistent Row suffix:

• product table → ProductRow
• order_item table → OrderItemRow
• variant_expiration table → VariantExpirationRow

Why flat: Entities are data structures that cross domain boundaries. ProductRow used in catalog, orders, inventory, and reporting contexts.

Entity Organization

All entities in single App\Entity namespace - avoid domain subdivision:

app/Entity/
├── ProductRow.php          ← Core business entities
├── OrderItemRow.php        ← Relationship entities
└── StockTransferRow.php    ← Operational entities

Entity Documentation Patterns

/**
 * @property-read int $id
 * @property-read string $title
 * @property-read bool $active
 * @property-read ?CategoryRow $category        ← nullable relationship
 * @property-read UserRow $author               ← required relationship
 */
final class ProductRow extends Table\ActiveRow
{
}

Documentation rules:

1. Document ALL accessible properties (including inherited id)
2. Use nullable types for optional foreign keys
3. Include relationship properties for IDE navigation
4. Match database schema exactly

Entity Relationships in phpDoc

Foreign key patterns:

• @property-read ?CategoryRow $category for optional relationships
• @property-read UserRow $author for required relationships
• @property-read Selection<OrderItemRow> $order_items for back-references

Naming convention: Follow Nette Database relationship naming (foreign key without _id suffix).

When to Use Selection API

Use for:

• Simple filtering and sorting
• Standard CRUD operations
• Queries that benefit from lazy loading
• When you need to chain conditions dynamically

return $this->db->table('product')
	->where('active', true)
	->where('category_id', $categoryId)
	->order('name');

When to Use Raw SQL

Use for:

• Complex analytics and reporting
• Recursive queries (WITH RECURSIVE)
• Performance-critical queries
• Complex joins that are awkward in Selection API

return $this->db->query('
	WITH RECURSIVE category_tree AS (...)
	SELECT ...
', $params)->fetchAll();

Query Building Patterns

Progressive refinement - start with base methods, refine with conditions:

Always use generic types for Selection returns:

/** @return Selection<ProductRow> */
public function getProducts(): Selection
{
	return $this->db->table('product');
}

/** @return Selection<ProductRow> */
public function getActiveProducts(): Selection
{
	return $this->getProducts()->where('active', true);
}

/** @return Selection<ProductRow> */
public function getProductsInCategory(int $categoryId): Selection
{
	return $this->getActiveProducts()
		->where(':product_category.category_id', $categoryId);
}

Benefits: Reusable base queries, clear evolution of filtering logic, easy testing. Benefits: Full IDE support, type safety, clear contracts.

Relationship Navigation

Use colon notation for efficient joins:

// Forward relationship (via foreign key)
->where('category.slug', $categorySlug)

// Back-reference (reverse relationship)
->where(':order_item.quantity >', 1)

// Deep relationships
->where('category.parent.name', 'Root Category')

Fetching Strategies by Use Case

Single optional result: ->fetch() All results as array: ->fetchAll() Key-value pairs: ->fetchPairs('key_column', 'value_column') Structured data: ->fetchAssoc('key_column->') Count only: ->count('*')

Schema Management

Use direct SQL migrations rather than ORM-style migrations:

• Store schema in sql/db.sql
• Manual migration scripts for schema changes
• Version control captures schema evolution

Database Constraints

Rely on database constraints for data integrity:

• Foreign key constraints for relationships
• Unique constraints for business rules
• Check constraints for data validation

Handle constraint violations in services with meaningful business exceptions.

Anti-Patterns to Avoid

Don't create separate Repository classes - combine data access with business logic in services. Don't use ActiveRecord for complex queries - raw SQL is cleaner for analytics and reporting. Don't fetch more data than needed - use appropriate fetching methods and SELECT only required columns for large datasets.

Error Handling Strategy

Service Level Error Handling

Transform database errors to business exceptions:

try {
	$customer->update(['email' => $newEmail]);
} catch (Nette\Database\UniqueConstraintViolationException) {
	throw new EmailAlreadyExistsException();
}

Handle at service boundary - presenters should receive business exceptions, not database exceptions.

Database Configuration

database:
	dsn: 'mysql:host=127.0.0.1;dbname=myapp'
	user: root
	password: secret
	options:
		lazy: true              # Connect on first query
		charset: utf8mb4        # Default
		convertBoolean: true    # TINYINT(1) to bool
		newDateTime: true       # Return DateTimeImmutable

Multiple connections:

database:
	main:
		dsn: 'mysql:host=127.0.0.1;dbname=app'
		user: root
		password: secret

	logs:
		dsn: 'mysql:host=127.0.0.1;dbname=logs'
		user: logs
		password: secret
		autowired: false  # Must reference explicitly

Reference non-autowired connection:

services:
	- LogService(@database.logs.connection)

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Online Documentation

For detailed information, fetch from doc.nette.org:

• Database Core - SQL queries
• Database Explorer - ORM-like API
• Configuration - connection setup