JunctionTable Class

The JunctionTable class extends Table for defining many-to-many relationship tables. Junction tables store associations between two entities using foreign keys and compound primary keys.

For conceptual overview and usage patterns, see Junction Tables.

Key Differences from Table

Junction tables differ from regular entity tables in that they:

• Have compound primary keys (multiple columns)
• Store only foreign keys (no additional data by default)
• Use composite indexes for bidirectional lookups

Example

<?php

namespace App\Service\Datastores\PostTag;

use PHPNomad\Database\Abstracts\Table;
use PHPNomad\Database\Factories\Column;
use PHPNomad\Database\Factories\Index;

class PostTagsTable extends Table
{
    public function getUnprefixedName(): string
    {
        return 'post_tags';
    }

    public function getSingularUnprefixedName(): string
    {
        return 'post_tag';
    }

    public function getAlias(): string
    {
        return 'pt';
    }

    public function getTableVersion(): string
    {
        return '1';
    }

    public function getColumns(): array
    {
        return [
            new Column('post_id', 'BIGINT', null, 'NOT NULL'),
            new Column('tag_id', 'BIGINT', null, 'NOT NULL'),
        ];
    }

    public function getIndices(): array
    {
        return [
            // Compound primary key
            new Index(['post_id', 'tag_id'], 'primary', 'PRIMARY KEY'),
            
            // Indexes for both directions
            new Index(['post_id'], 'post_idx', 'INDEX'),
            new Index(['tag_id'], 'tag_idx', 'INDEX'),
        ];
    }
}

What's Next

• Junction Tables — complete guide
• Table Class — entity tables