Database Migration

What is the Data Migration Tool?

Magento's official tool for migrating data from Magento 1 to Magento 2:

# Install via Composer
composer require magento/data-migration-tool

# Or if already installed
bin/magento migration:data --help

Migration Process

1. Settings Migration   → System configuration, websites, stores
2. Data Migration       → Products, customers, orders, CMS
3. Delta Migration      → Incremental changes during migration
4. Go Live              → Final delta sync and switch

Configuration Files

vendor/magento/data-migration-tool/etc/
├── config.xml.dist          # Main configuration
├── map.xml.dist             # Table mapping
├── class-map.xml.dist       # PHP class mapping
└── settings.xml.dist        # Settings mapping

For each version:
├── open-source/
│   ├── 1.9.3.x/
│   │   ├── map.xml.dist
│   │   └── class-map.xml.dist
│   └── ...
└── commerce/
    └── ...

config.xml

<!-- app/code/Vendor/Module/etc/config.xml -->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:data-migration-tool:config/etc/config.xsd">
    <steps mode="settings">
        <step title="Settings Step">
            <migration\Settings\Step\SettingsStep/>
        </step>
    </steps>
    <steps mode="data">
        <step title="Data Step">
            <migration\Data\Step\DataStep/>
        </step>
    </steps>
    <groups clickzitt="settings">
        <step title="Settings Step">
            <migration\Settings\Step\SettingsStep/>
        </step>
    </groups>
</config>

Source and Destination Configuration

<!-- etc/config.xml -->
<config>
    <source>
        <database>
            <host>localhost</host>
            <username>magento1_user</username>
            <password>password</password>
            <dbname>magento1_db</dbname>
            <prefix>m1_</prefix>
        </database>
    </source>
    <destination>
        <database>
            <host>localhost</host>
            <username>magento2_user</username>
            <password>password</password>
            <dbname>magento2_db</dbname>
            <prefix>m2_</prefix>
        </database>
    </destination>
</config>

Table Mapping

<!-- map.xml.dist -->
<map>
    <source>
        <table name="m1_catalog_product_entity">
            <rule>
                <field name="*">skip</field>
            </rule>
        </table>
    </source>
    <destination>
        <table name="m2_catalog_product_entity">
            <rule>
                <field name="*">map</field>
            </rule>
        </table>
    </destination>
</map>

Migration Commands

# Step 1: Settings migration
bin/magento migration:settings --mode=settings etc/config.xml

# Step 2: Data migration
bin/magento migration:data etc/config.xml

# Step 3: Delta migration (for live sites)
bin/magento migration:data --delta etc/config.xml

# Step 4: Incremental updates
bin/magento migration:delta etc/config.xml

Migration with Custom Rules

// Custom data transformer
class CustomProductTransformer implements \Migration\Handler\HandlerInterface
{
    public function handle($value)
    {
        // Transform data during migration
        return ucfirst(strtolower($value));
    }
}

// In map.xml
<map>
    <source>
        <table name="m1_catalog_product_entity">
            <field name="name" handler="CustomProductTransformer"/>
        </table>
    </source>
</map>

Version Upgrade Migration

# For upgrades within Magento 2
bin/magento setup:upgrade

# This runs all pending:
# - Schema patches (db_schema.xml changes)
# - Data patches (new data installations)
# - Setup scripts (InstallSchema, InstallData)

# Check upgrade status
bin/magento setup:db:status

Migration Progress

# Check migration status
bin/magento migration:data --status etc/config.xml

# Output:
+----------+---------+--------+
| Step     | Status  | Mode   |
+----------+---------+--------+
| Settings | Complete| ---    |
| Data     | 75%     | ---    |
| Delta    | Pending | ---    |
+----------+---------+--------+

Pre-Migration Checklist

1. Backup both databases
2. Verify Magento 2 meets system requirements
3. Install and configure Data Migration Tool
4. Test migration on development environment
5. Document custom modules and data
6. Plan downtime window
7. Notify stakeholders

Common Migration Issues

Post-Migration Tasks

# Reindex all
bin/magento indexer:reindex

# Flush cache
bin/magento cache:flush

# Generate URL rewrites
bin/magento urlrewrite:reindex

# Verify data
bin/magento catalog.product:count
bin/magento customer:count
bin/magento sales:order:count

# Test critical paths
# - Product listing
# - Cart/Checkout
# - Customer login
# - Admin panel

Custom Module Migration

// Create custom migration script
class MigrateCustomModuleData implements DataPatchInterface
{
    public function install(): void
    {
        $this->setup->startSetup();
        $connection = $this->setup->getConnection();

        // Migrate from M1 custom table to M2
        $sourceTable = 'm1_custom_module_data';
        $destTable = $this->setup->getTable('vendor_module_data');

        if ($connection->isTableExists($sourceTable)) {
            $data = $connection->fetchAll("SELECT * FROM $sourceTable");
            foreach ($data as $row) {
                $connection->insert($destTable, [
                    'name' => $row['name'],
                    'status' => $row['status'],
                ]);
            }
        }

        $this->setup->endSetup();
    }
}